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Managing fatiguein the workplaceA guide for oil and gas industrysupervisors and occupationalhealth practitioners

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OGP Report Number 392

IPIECAInternational Petroleum Industry Environmental Conservation Association

5th Floor, 209–215 Blackfriars Road, London SE1 8NL, United Kingdom

Telephone: +44 (0)20 7633 2388 Facsimile: +44 (0)20 7633 2389

E-mail: [email protected] Internet: www.ipieca.org

OGPInternational Association of Oil & Gas Producers

London office

5th Floor, 209–215 Blackfriars Road, London SE1 8NL, United Kingdom


E-mail: [email protected] Internet: www.ogp.org.uk

Brussels office

Boulevard du Souverain 165, 4th Floor, B-1160 Brussels, Belgium


E-mail: [email protected] Internet: www.ogp.org.uk

This document was compiled on behalf of the OGP-IPIECA Health Committee by a team of

consultants, oil and gas industry medical and human factors advisors, and sleep and fatigue

specialists.The committee gratefully acknowledges the assistance of the following:

Dr Alex Barbey (Schlumberger),

Dr Graham Reeves (BP), Dr David Flower (BP), Dr Frano Mika (Saipen)

Isabelle Arnulf MD PHD (Assistant Professor, Pierre and Marie Curie University, Paris, France)

Dr Alexandra Holmes (Clockwork Consultants)

© IPIECA/OGP 2007. All rights reserved. No part of this publication may be reproduced, stored in a retrievalsystem, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording orotherwise, without the prior consent of IPIECA/OGP.

Disclaimer: Information provided herein is offered in good faith as accurate, but without guarantees orwarranties of completeness or accuracy. Readers are hereby put on notice that they must rely on their owndiligence when determining how or whether to respond to the information herein. Further, this guide is notintended to replace necessary and appropriate medical or other professional advice or attention.

This publication is printed on paper manufactured from fibre obtained from sustainably grown softwood forests and bleachedwithout any damage to the environment.

Managing fatigue in the workplaceA guide for oil and gas industry supervisors and occupational health practitioners

MANAGING FATIGUE IN THE WORKPLACEA GUIDE FOR OIL AND GAS INDUSTRY SUPERVISORS AND OCCUPATIONAL HEALTH PRACTITIONERS

ii

Contents

1 Purpose of this Guide

1 Why manage fatigue?

1 Accidents2 Performance2 Health

3 Sleep and the body clock

3 Why do we sleep?3 How much sleep do we need?4 Acute and cumulative sleep loss4 The consequences of sleep loss5 The body clock6 The body clock and sleep

7 Shift work

7 The health and safety consequences of shift work7 Do we adapt to shift work?8 Managing the fatigue risk associated with shift work8 Designing safer shift work arrangements

10 Personal countermeasures13 Sleep hygiene

14 Health and sleep disorders

14 Obstructive sleep apnœa (OSA)15 Insomnia16 Periodic limb movements in sleep16 Managing the risk of sleep disorders

17 Medication

17 Prescription medication17 Over-the-counter (OTC) medication

18 Jet lag

19 Resources and further reading

20 Appendix 1: Sleep hygiene

21 Appendix 2: Can you drive a vehicle safely?

22 Appendix 3: Do you suffer from obstructive sleep apnœa?

23 Appendix 4: Are you obese?

Purpose of this Guide

Why manage fatigue?


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Fatigue can be defined as a progressive declinein alertness and performance that results insleep. Fatigue is an everyday occurrence and inan ideal world would not pose a significanthealth and safety risk. The 24/7 society inwhich we live, however, insists that manypeople work outside of ‘standard’ office hoursand thus experience an elevated level of fatigue.Shift work, long work hours and internationaltravel can all promote fatigue. Other causes offatigue include medical disorders, such as sleepdisorders, medication, drugs and alcohol.

Excessive fatigue can have significantadverse outcomes for performance, health andwell-being. Fatigue impairs our performanceand—particularly in safety-critical industries—can contribute to serious incidents. Excessivefatigue affects millions of people around theworld, and costs billions of dollars per year inmedical expenses, accidents, injuries and lostproductivity.

This guide is intended primarily as a toolto assist oil and gas industry supervisors and

Accidents

Investigations into some of the worstindustrial and environmental accidents of thepast 30 years have identified fatigue as amajor contributory factor to the incident. Insome of these cases, fatigue was not the solecause. Rather, there was an initial difficultysuch as a technical fault, and because theoperators were fatigued they did not managethe situation adequately and the situationescalated to an accident.

Fatigue contributes to accidents byimpairing performance and at the extreme

occupational health practitioners tounderstand, recognize and manage fatigue inthe workplace.

The guide sets out to:● explain the health and safety risk posed by

fatigue;● provide the necessary background

information on sleep and the body clock;and

● describe the main causes of fatigue andprovide strategies for managing the causes.

It is recognized that the information andrecommendations given in this guide couldhave operational, manpower and financialimpact; however, the guidance is based onsound scientific principles and deviation fromthis guidance potentially increases the risk offatigue-related incidents. In the absence ofregulation the extent to which this guidance isapplied should be agreed between thestakeholders involved.

end of the scale by causing people to fallasleep.The UK Department for Transport hasestimated that at least 20 per cent of fatalroad accidents on UK motorways are theresult of a driver having fallen asleep at thewheel. Fatigue is particularly problematicamongst professional drivers; in the USAdriver sleepiness is estimated to havecontributed to 57 per cent of fatal accidentsinvolving trucks.

Figure 1 Comparison on the effects of sleep loss and alcohol on performance(BAC = blood alcohol concentration)

08:00 12:00 16:00 20:00 12:00

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cognitiveperformance


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Why manage fatigue?

Performance

The impact that fatigue can have onperformance and safety is not widelyrecognized and is generally underestimated.One of the key reasons for this lack ofawareness is that fatigue cannot be directlymeasured.There is no chemical in the bloodor any biological specimen that can give anaccurate indication of how tired someone is.

To improve our appreciation of fatigue andits consequences for performance, researchershave compared the effects of fatigue to those ofalcohol. Research has shown that after approx-imately 22 hours of wakefulness a person’sperformance will be as impaired as if they hada blood alcohol concentration (BAC) of0.10 per cent, which is double the legal drivinglimit in most countries in the EU (Figure 1). Inother words, one night of sleep deprivation canproduce performance impairment significantlygreater than what would be acceptable if youwere driving a vehicle.

Our performance is impaired when we arefatigued quite simply because fatigue reduces(deactivates) the electrical activity of someregions of our brain (see Figure 2). Reductionsin activation are especially evident in prefrontalcortices (the highlighted region to the right)—which control functions like situational

awareness and problem-solving; the inferiortemporal cortices (the highlighted region tothe left) which are important for mental taskssuch as mathematical calculation; and thethalamus (central highlighted region) whichcontrols general alertness levels and attention.

Health

We all know from personal experience thatfatigue can make us irritable and short-tempered.In addition to having a negative impact onmood, fatigue has adverse consequences forhealth.There is increasing evidence to suggestthat sleep loss is a risk factor for obesity anddiabetes. In a recent study subjects who sleptonly four hours a night for two nights had an18 per cent decrease in the hormone that tellsthe brain there is no need for more food(leptin), and a 28 per cent increase in thehormone that triggers hunger (ghrelin).

Shift workers encounter a particularly highdegree of sleep loss and it seems likely thatfatigue plays a role in the health complaintsencountered by this group. Researchers haveconcluded that shift work is ‘probably bad forthe heart, almost certainly bad for the headand definitely bad for the gut’ (Monk andFolkard, 1992).

Figure 2 Fatigue reduces the electrical activity in some regions of the brain, andhence impairs performance. The highlighted areas indicate the areas of thebrain in which the reduction of activity is especially evident.

Prefrontal cortices (situational awareness, problem solving)

Inferior temporalcortices (mathematicalcalculation)

Thalamus (general alertnessand attention levels)

Adap

ted

from

Thom

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t al.,

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Sleep and the body clock


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There are a multitude of causes of fatigueranging from long work hours, high workloadand jet lag to intense domestic demands,health and drug/alcohol use.These factors cancause fatigue in a number of ways, forexample by presenting demanding mental orenvironmental conditions, by promotingdehydration or increasing stress. Nonetheless,the prime underlying mechanisms via whichfatigue is generated are insufficient sleep,prolonged wakefulness, being awake whenone would normally be sleeping or trying tosleep during the day. This section providesbackground information on sleep and thebody clock required to understand andmanage fatigue.

Why do we sleep?

One answer to the question ‘why do wesleep?’ is because without sleep we aredebilitated by fatigue and cannot survive.However, the actual purpose of sleep is stillnot completely understood. It is not simplythe case that during sleep we ‘switch off ’.Sleep is a highly complex physiological

process throughout which the brain is active,and some parts of the brain are as activeduring sleep as when we are awake. It seemslikely that sleep serves a variety of purposes,including tissue repair and the consolidation ofmemory and learning.

How much sleep do we need?

Just as we all vary in how quickly alcoholaffects us and how easily we lose or gainweight, we also differ in the amount of sleepthat we need to perform optimally. Mostadults need 7 to 8 hours of sleep in every 24hours to be at their best, and a smallproportion need as little as 6 hours or asmuch as 10 hours sleep. By necessity orchoice sometimes we only obtain four or fivehours sleep.While we can certainly functionon this amount of sleep the important pointto remember is that we will not be capable ofour optimal performance.

The amount of sleep that you ideally needis not something you can change. Forexample, if your daily sleep requirement isnine hours and you regularly obtain six hours

If you want to determine how much sleep you needto perform optimally, you can do so next time youare on holiday by following these steps:

● Put your alarm clock away and arrange your dailyschedule so that you can wake up naturally everymorning.

● Allow at least two days to overcome any existingcumulative sleep loss.

● For the next three or four days, write down thetime you go to bed at night and what time younaturally wake up in the morning.

● Calculate the average amount of sleep you obtainfor these three or four days. This is the amount ofsleep you require for optimal alertness,performance and well-being.

How to determine your personal sleep need


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your body will not learn or adapt to gettingless sleep. You may become accustomed tofeeling tired, to the point that you don’t evenrecognize it any more, but you will alwaysrequire nine hours to be at your best.

Acute and cumulative sleep loss

Sleep loss can be either acute (losing a largeproportion of one night’s sleep), for example asa result of having to stay awake with a sickchild, or more commonly, cumulative (regularlylosing sleep over many nights), for example asthe result of working a sequence of consecutiveearly shifts. Scientists have compared the effectsof acute and cumulative sleep loss and foundthat both forms of sleep loss result in reducedlevels of alertness or performance. A study inwhich sleep was restricted to between four andsix hours per night for a fortnight found thatcognitive performance, including attention andworking memory, gradually deteriorated fromone day to the next. By the end of the two-week period, performance had declined to asimilar level to when the same people werekept awake continuously for between 24 and48 hours.

Two nights of good quality sleep shouldusually be sufficient to enable you to recover


from acute sleep loss, i.e. you don’t need tomake up the lost sleep on an hour-for-hourbasis. However, when you have lost sleep overrepeated days you accumulate a ‘sleep debt’.The amount of sleep required to recover fullyfrom this sort of cumulative sleep loss is notyet known, but it is likely to be longer thantwo nights of sleep.

The consequences of sleep loss

Research has shown that for most people evenone night of six hours sleep will lead toimpaired performance the next day. Obviouslythe more sleep deprived we are the moreimpaired we become.

Figure 3 illustrates the physical and cognitivesigns of fatigue, in increasing severity, that canbe observed as fatigue progresses until thepoint that we are falling asleep uncontrollably.

Figure 3 The physical signs and cognitive symptoms of increasing fatigue

fidgeting, moving

around in seat

rubbing eyes

repeated yawning

staring blankly, eyes

going in and out of focus

frequent/long blinks

difficulty keeping

eyes open

head nodding

negative mood

reduced

communication

slips and lapses

poor memory

reduced attention

impaired problem solving

increased risk taking

A L E R T

A S L E E P

physical

signs

cognitive

signs


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The cognitive signs of fatigue include:

i) Negative moodFatigue has a negative impact on ouremotions and reduces our tolerance for whatis going on around us.When we are fatiguedwe become irritable and are more easilyfrustrated. Fatigue makes us feel lethargic andlacking in initiative and motivation.We have areduced willingness to interact with others.

ii) Reduced communicationFatigued people have both a reducedwillingness and a reduced ability tocommunicate.When we are fatigued we tendto use less descriptive language and mayneglect to pass on important information tocolleagues; this can be particularly problematicduring the changeover of shift teams.

iii) Slips and/or lapsesAn increase in slips and/or lapses is one of theeasiest cognitive signs of fatigue to detect. Aslip is defined as accidentally doing the wrongthing, for example picking up the wrong tool,while a lapse is defined as accidentally notdoing the right thing, for example forgettingto tighten a nut.

iv) Poor memoryFatigue impairs our short-term memory so thatwe do not always remember what we havedone and what has not been done.When weare tired we may not be able to recall recentconversations or information we have read.

v) Reduced attentionFatigue decreases our ability to maintainattention. When fatigued we find it moredifficult to divide our attention appropriatelybetween multiple tasks and to plan for futureactions.We are more likely to suffer lapses inconcentration and are more easily distractedfrom the task at hand.

Fatigue can lead us to become fixated on

one particular task.This ‘narrowing of focus’or ‘cognitive tunnelling’ can cause us to paytoo much or insufficient attention toperipheral events and auxiliary tasks.

vi) Impaired problem solvingFatigue disrupts many of the processes involvedin effective problem solving, including: theidentification and evaluation of alternativecourses of action; construction of mentalimages; and the integration of incominginformation with existing knowledge. Whenfatigued we tend to persevere with ineffectivesolutions, to keep trying the same old solutioneven if it doesn’t work.

vii) Increased risk takingFatigue affects our ability to assess risks andincreases our willingness to accept risks.Themore tired we become, the more likely we areto cut corners and to accept lower standardsin accuracy and performance.

The body clock

All living beings, including plants, animals andhumans, are regulated by 24-hour biologicalrhythms, known as circadian rhythms, whichprime us for activity during the day and sleepduring the night. In humans the source ofcircadian rhythms is the body clock, which isprimarily located in a cluster of cells in thebrain. The body clock is comparable to theconductor of a symphony orchestra. Itinstructs almost all of the body systems,including the sleep/wake cycle, cardiovascularactivity and hormone secretion, to vary in acircadian rhythm.

Figure 4 (overleaf) shows the circadianrhythm in sleepiness. Sleepiness is relativelylow in the evening and increases late at nightto reach a peak in the early hours of themorning (approximately 02:00 to 04:00). Itthen declines and remains low during the day,except for a second small increase that occurs


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in the afternoon (approximately 13:00–15:00).The pattern repeats itself every 24 hours.

The early morning circadian peak insleepiness coincides with an increase in fatigue-related accidents that occurs at this time of day(see Figure 5). Research conducted in the UKhas found that 32 per cent of fatigue-relatedroad accidents on motorways occur in theearly hours of the morning. Shift workersreturning home from a night shift areparticularly likely to be involved in roadaccidents at this time of day.The small increasein sleepiness that occurs in the afternoon is thereason why some cultures take a nap or a siestaafter lunch. From Figure 5 you can see there isalso a small increase in fatigue-related accidentsat this time of day.

The body clock and sleep

The circadian rhythm in sleepiness has animportant influence on sleep and ensures thatwe get most sleep when we go to bedbetween about 22:00 and 02:00. It is also thereason why we have most difficulty sleepingbetween approximately 08:00 and 12:00 noon,and again between 17:00 and 21:00. Thesetimes are known as ‘forbidden zones’ for sleep.The forbidden zone in the evening is animportant reason why sleep loss is problematicwhen working early shifts. Employees may tryto go to sleep early knowing they have to beawake at 04:00 but the forbidden zone preventsthem from falling asleep until around 22:00.


Figure 4 The circadian rhythm in sleepiness

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Figure 5 Road traffic accident risk over the 24-hour day(mean trend, and standard errors)

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Shift work


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The health and safety consequences ofshift work

Most people understand intuitively what ismeant by the term ‘shift work’ although theactual definitions vary from region to regionand country to country. In the UK, forexample, it is referred to as ‘night work’ as partof the European working time directive.Night work is defined as work between thehours of 23:00 and 06:00. Employees shouldbe considered as ‘night workers’ if their dailyworking time includes at least three hours ofwork at night:● on most days they work;● on a proportion of the days they work

which is specified in a collective orworkforce agreement; or

● often enough for it to be said that theywork such hours ‘as a normal course’.

The words ‘as a normal course’, means on aregular basis. There has been a Court rulingthat a worker who worked at night for one-third of his working time was a night worker.Occasional or ad hoc work at night does notmake an employee a night worker.

For people working ‘typical office hours’work and sleep occur at times that are alignedwith the timing of the body clock. Work isscheduled for daytime hours when alertness ishigh and sleep is initiated when the bodyclock has prepared the body for sleep. For the15–20 per cent of the working population inindustrialized countries that are involved inshift work, however, work and sleep occur attimes of the day which conflict with theunderlying body clock.

Shift workers encounter fatigue because theyneed to sleep when the body is programmedfor wakefulness and are at work when thecircadian rhythm in sleepiness is high. Thedegree of fatigue that shift workers encounterdepends on the schedule that is being worked,but is generally most severe on night shifts and

shifts that start early in the morning.Unpredictable work hours, for example call-outarrangements, are also particularly problematic.

An additional disadvantage to shift work isthat it can lead to feelings of isolation and torelationship difficulties. Shift work can placeadded strain on social and personalrelationships.Working shifts can also make itdifficult to lead a healthy lifestyle, for exampledue to eating irregularly and at times that areout of synch with the body’s natural rhythmsand by making it more difficult to keep to anexercise schedule.

Research has shown that, in the long term,there is an association (but not necessarily acausation) between shift work and increasedincidences of:● domestic disharmony;● gastrointestinal problems, including peptic

ulcers;● cardiovascular disease, including hypertension

and coronary heart disease;● spontaneous abortions, miscarriages and

premature births in pregnant women; and● possibly breast and colon cancer.

The causation of all these conditions ismulti factorial.

Do we adapt to shift work?

Daily cues (known as ‘zeitgebers’) ensure thatthe timing of our body clock matches the24-hour period of day and night. The mostimportant zeitgeber is light and this influencesthe body clock via receptors in the eye. Otherzeitgebers include temperature, activity andfood. When we work shifts or travel to adifferent time zone, the timing of zeitgeberschanges. In response, the timing of our bodyclock gradually changes so that eventually itmatches the new timing of the zeitgebers.

After travelling across a time zone thetiming of all zeitgebers is similarly changed. Asa result, the body clock can usually shift by


8

approximately 30 to 60 minutes per day andsuccessful adaptation eventually occurs.

In contrast, when working shifts the timingof zeitgebers that are associated with work arechanged, while those associated with theenvironment remain the same. For example,the times that you are active and are asleepchange, but you may still eat at normal timesand are exposed to sunlight during the day.These mixed messages mean that the timingof the body clock changes very slowly andsuccessful adaptation to shift work almostnever occurs. In addition, any adaptation thatoccurs over a block of shifts is usually undoneon days off when shift workers revert to theroutine of their family and friends.

Managing the fatigue risk associatedwith shift work

Fatigue Management Plans (FMPs) arebecoming increasingly common in safetycritical industries including the oil and gasindustry. An FMP is a framework designed toenable operational and employee concernsregarding fatigue to be addressed in a preven-tative manner. The aim of an FMP is tomaintain, and when possible, enhance safety,performance and productivity and manage therisk of fatigue in the workplace.

FMPs typically include the followingfundamental components (Baker andFerguson, 2004):

a) PolicyA document formally outlining the approach,commitment and accountability, including arequirement for internal and external auditingprocesses.

b) TrainingA training and education programme toenable employees and managers to identify thesigns and symptoms of fatigue, and to adoptcoping strategies in and outside the workplace.

c) Tracking incidents: metrics A programme for the tracking andunderstanding of all incidents, accidents andnear misses.These events should be plotted fortime of day, day of roster, hours of priorwakefulness and sleep length in order todetermine the role that the roster and sleeploss may have played in the event.

d) SupportMedical and well-being support that includesdiagnosis of sleep disorders and other healthproblems causing sleep disturbance, treatmentof sleep problems and, where necessary,referrals to general practitioners, psychologists,counsellors and sleep clinics.

Designing safer shift workarrangements

Within the framework of an FMP it isnecessary to assess the risks associated with theschedules being worked. There are manydifferent shift work schedules, each withdifferent features.The sheer diversity of workand workplaces means that there is no singleoptimal shift system that suits everyone.However, there are a number of key riskfactors in shift schedule design, which shouldbe considered when assessing and managingthe risks of shift work.These are the workload,the work activity, shift timing and duration,

Shift work


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direction of rotation and the number andlength of breaks during and between shifts.Other features of the workplace such as thephysical environment, management issues andemployee welfare can also contribute to therisks associated with shift work.

Good practice guidelines for shift design ● Plan an appropriate and varied workload.● Where employees are working rotating

shifts these should be forward rotating (e.g.earlies, days, lates).

● Ideally, where rotating shifts are operated,rotation should be rapid (e.g. every two tothree days).

● Avoid early morning starts. Shift change-over time should take into account thelength of commute and the availability ofpublic transport.

● Limit shifts to 12 hours including overtime.● Encourage workers to take regular breaks

and allow some choice as to when they aretaken.

● Consider the needs of vulnerable workers,such as young workers, and new andexpectant mothers.

● The aging workforce brings with itadditional challenges in managing shiftoperations.

● Limit consecutive work days to a maximumof five to seven days and restrict long shifts,nights and earlies to two to three con-secutive shifts.

● Allow two nights of full sleep whenswitching from days to night shifts and viceversa.

● Build regular free weekends into the shiftschedule.

Good practice guidelines for the workenvironment ● Provide night workers with similar facilities

(e.g. canteen, food storage and preparation)and access to training opportunities tothose available during daytime.

● Ensure temperature and lighting isappropriate and preferably adjustable.

● Provide training and information on therisks of shift work and ensure supervisorsand management can recognize problems.

● Consider increasing supervision duringperiods of low alertness.

● Control overtime, shift swapping andon-call duties and discourage workers fromtaking second jobs.

● Allow time for communication at shifthandovers.

● Provide opportunities for interactionbetween shift workers and support for loneworkers.

● Encourage workers to tell their familydoctor and occupational health physicianthat they are shift workers.

● Provide free health assessments for nightworkers, the content of which should focuson relevant health issues.

● Ensure the workplace and surroundings arewell lit, safe and secure.

Additional considerations: offshore unitsand drilling rigsOffshore shift systems tend to be differentfrom those onshore in that they are 12 hoursin duration for periods of 14 to 21 days. ‘Splitshifts’ where operators work 7 nights followedby 7 days are also common.This shift is verydifficult to adapt to as operators are ‘out ofphase’ for 5 of the 7 nights and then go outof phase again for the following 4 to 5 days.However, this shift is favoured becauseoperators are adjusted to a normal day/nightcycle at the end of their tour.

Evidence suggests that a 7-day/7-night shiftwould be better but this means operatorswould have to spend the first few days backonshore recovering from nights. On arrivalback onshore many operators will also be tiredfollowing their last night shift and consequentlymay not be fit enough to continue theirjourney home by car. Alternative methods of


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travel, including car sharing (pooling) and orthe provision of suitable facilities in whichoperators could rest (take an extended nap)would need to be explored.

At present the most favoured offshore shiftschedule would appear to be 14 days and 14nights operating between 06:00–18:00–06:00.Operational units working a 14-dayon/21-day off shift pattern should considermoving to this schedule.

Researchers have also predicted that a14-day/14-night schedule operating between00:00–12:00–00:00 would be better and havespeculated that a schedule operating between03:00–15:00–03:00 would be better still.

Research also indicates that it might bepossible to improve adaptation with carefullytimed light treatment; careful timing of mainsleep periods; and the use of napping duringnight shifts, particularly during the first nightof a tour.

Rapid shift rotation is not advocatedoffshore. Safety critical tasks should not bescheduled during circadian low points(03:00–05:00). Review manning and workloadlevels and consider appointing additionalmulti-skilled staff who are able to cover staffshortages arising because of fatigue or whocan assist/help with safety critical tasks thatcannot be rescheduled.

Extended tours of dutyEach operating unit should have a work timecontrol process in place which describesnormal shift pattern rotation schedules, routinework periods, control process and contingencyarrangements to deal with the occasionalcircumstances when the standard cannot becomplied with.

Sleep debt will build when working forextended periods without a break. Night shiftworkers’ performance, in particular, willdecrease as the tour progresses.Workload/taskassignment/staffing levels may need to beamended/modified to reflect this. Recom-

mendations include monitoring for adverseeffects, scheduling safety critical tasks for thesafest period of the shift and verifying thatthese have been completed correctly.

Personal countermeasures

How well an individual copes with shift workis dependent on a range of factors includingtheir age, the ease with which childcarearrangements can be organized, commute timeand their health.Young adults seem to copebetter with shift work than older workers, onereason being because from middle ageonwards the structure of our sleep changes.With increased age we spend less time in deepsleep and our sleep becomes more disrupted.

The degree of training and support thatemployees require to fulfil their responsibilitieswithin an FMP will vary between organizations

Shift work

Maximum working hourswithin a 24 hour period

Maximum number ofworking days per tour

Work breaks (includingmeals) during a working shift

12 hours total

28 days includingtravel to and from site

Minimum of 30 mins.break after every 5 hrs.

Suggested requirements

Extended tours of duty

Offshore platforms

Maximum working hourswithin a 24 hour period

Maximum number ofworking days per tour

Work breaks (includingmeals) during a working shift

Direction of shift rotation

Speed of rotation

12 hours total

28 days includingtravel to and from site

Minimum of 30 mins.break after every 5 hrs.

Morning then evening

Shift should rotateover a long period oftime and as aminimum every 7 days


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and populations. However, education aboutpersonal countermeasures to assist individuals tocope with shift work is essential.

The following sections provide suggestionsfor shift workers that may help them copebetter with their work hours:

At work● Schedule tedious and boring tasks for times

of the day when alertness is high, and leavethe stimulating and motivating tasks fortimes of the day when alertness is lower.

● Use a ‘buddy system’ so that colleagues helpto keep each other alert and encouragebreaks if signs of drowsiness appear.

● Exercise, walk around or do some physicalactivity during breaks.

● Use caffeinated drinks (coffee, tea, colas)strategically—avoid them at times whenyou are alert and use them as acountermeasure when alertness is low.

● Advise your supervisor if you have hadinsufficient sleep, feel tired or are exhibitingany of the signs and symptoms of fatigueoutlined in Figure 3.

● For many shift workers the most high-risktask that they perform is driving home inthe morning or at the end of a tour ofduty. If possible, avoid driving home byusing an alternative form of transport orarranging a lift. If you have to drive ensureyou are properly rested before setting off.

NapsNaps can be used to prepare for, or recoverfrom, work (e.g. before a night shift or after anearly start), before driving home and, whereappropriate, at work. During the night shiftthe best time to nap is between approximately04:00 and 06:00. Obviously, the longer a napthe greater the benefit it will have foralertness. If you nap for longer than 30minutes, however, you need to give yourselftime to recover from sleep inertia—the groggyfeeling that we experience when we wake

from a deep sleep which results in poorcoordination and cognitive impairment.

A ‘power nap’ of 15 to 20 minutes is notas beneficial as a longer nap but it does avoidthe problem of sleep inertia.You can enhancethe value of a nap by consuming somecaffeine just before the nap. Caffeine takesabout 20 minutes to take effect so when youwake up from the nap you will beexperiencing the alerting properties of boththe nap and the caffeine.

At homeTo improve the degree to which employeescope with shift work they will need the helpof their families and friends. Below are someof the things that they can do at home toimprove their quality of life:

Try to schedule your social/domesticresponsibilities around sleep● Explain to your family/friends why it is

important that you obtain sufficient sleepand the consequences that tiredness canhave for you, them and safety.

● At the same time, schedule special times forfamily and friends so they know when toexpect to spend time with you.

● Put your roster on the fridge (orsomewhere prominent) so others knowwhen you will be at home and at work.

● Use a ‘Do not disturb’ sign on the bedroomdoor.

Diet and exerciseA healthy diet provides longer-lasting energy—concentrate on complex carbohydrates (e.g.oats) rather than simple carbohydrates (sugar)and avoid fatty foods and junk food. Contraryto some speculations, there is no scientificevidence that some foods (e.g. turkey) promotesleep. Nonetheless, sitting down to have a glassof warm milk before bed can be relaxing,particularly if part of a bedtime routine.


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Most of us are aware of the benefits ofexercise, but did you know that physicalexercise can improve your sleep? Regularexercise taken earlier in the day can be aneffective aid for sleeping, partly because it is ameans of relieving stress. It is important thatyou don’t exercise just before sleep though asthe adrenalin released during exercise canmake it difficult to get to sleep.

Avoid alcohol and nicotineMany people believe that drinking alcohol canhelp them get a good night’s sleep. However,while it is true that alcohol has a relaxing andsedative effect, it actually disrupts sleep.Alcohol increases the likelihood of snoring,causes early awakening, disrupts sleep qualityand increases fatigue the next day.When usedby individuals suffering from insomnia orobstructive sleep apnœa (see ‘Health and sleepdisorders’ on page 14), alcohol increases theseverity of the sleep disorder.

If you smoke, avoid smoking cigarettesimmediately before going to bed: nicotine is amild stimulant and may increase the amountof time that it takes you to fall asleep.

Evening preparationDuring the evening as bedtime approaches thereare a number of strategies that can be

implemented to promote sleep.These strategiesconcentrate on helping you to gently unwindand prepare both your body and mind for sleep.● Unwind by avoiding anxiety

In the hours before bedtime avoid activitiesthat will make you mentally active oranxious. Using the internet or playingcomputer games prior to bedtime can makeit more difficult to unwind for sleep.

● Have a warm shower or bathAnother particularly useful strategy forpromoting sleep and relaxation is to take awarm bath or shower. Research has shownthat we fall asleep faster when we havewarm feet.

● Being too full or hungryObviously going to bed hungry candisturb your sleep. A light snack beforebed, such as a bowl of cereal with milk,can stave off hunger pangs during thenight. To avoid being kept awake byindigestion steer clear of acidic, spicy orhigh fat foods. Another reason for avoidingfat and sugar in the evening is that ourmetabolism falls to its lowest point atnight, meaning we are less likely to burnoff the extra calories.

● Write a ‘to-do’ listMake a list of things to do before you gointo the bedroom. Rather than lying awakeand worrying about forgetting things thatyou have to do, keep a pen and paper byyour bed.

● Establish a bedtime routineTo train your mind and body to prepare forsleep you should establish a consistentbedtime routine. By following the samepattern of daily behaviour, over time yourbody will come to associate this with sleep.

An example routine could be: to switcheverything off downstairs, lock the frontdoor, have a light snack, a relaxing bath,brush teeth, prepare clothes for tomorrow,get into bed, set alarm clock, read for 15minutes, and put the light out.

Shift work


13

Prepare an ideal bedroom environment● Keep the bedroom for sleep

It goes without saying that the bedroomshould be comfortable and relaxing, but alltoo often we treat our bedrooms as anextension of our living rooms or offices.Thebedroom should be reserved for sleep andintimate relations, and not for surfing theinternet or other activities that will makeyou mentally active or anxious. Removedesks, computers and even televisions asthese can all prevent you from relaxing.Taking away these items will eventually leadyou to naturally associate the room withsleep and to feel calm when you enter.

● Block out lightStreet lights, daylight and the light from atelevision can all upset circadian rhythmsand send a signal to the brain that it is timeto wake up. Try to keep your bedroom asdark as possible by fitting heavy curtains.Alternatively, wear an eye mask.

● Keep your bedroom quietBelow are some of the basic things you cando to help minimize the chances that youwill be disturbed by noise when trying tosleep:• Turn off the phone and switch your

mobile phone off or to silent mode;• Put a ‘Do not disturb’ sign on the front

door;• Use ear plugs or fit double glazing;• Use a source of white noise (e.g. a fan).

● Keep your bedroom coolOur ability to regulate our bodytemperature is diminished when we areasleep. Therefore, if during the night it istoo cold or too hot we spend more time inthe lighter stages of sleep, or awake (so thatwe can control temperature better). Wesleep best when the bedroom temperatureis slightly cool (approximately 18˚C).

● Ensure your bed is comfortableAs a rule your bed should be neither toohard nor too soft. If your mattress is lumpyor worn it is worth investing in a newone: after all, you spend a third of your lifein bed.

Your pillow can also affect your sleep.Depending on what position you sleep inyou may need a different type of pillow. Ifyou sleep mainly on your stomach a softpillow may be best for you. If most of thetime you sleep on your back you maybenefit from a medium pillow, whereas ifyou sleep on your side you may prefer afirm pillow. If you have back or neck painduring sleep or when you awake, you willprobably benefit from a contour pillow,which can minimize the strain on yourneck during the night.

Sleep hygiene

Appendix 1 provides a list of undesirable sleephygiene practices. This can be used to raiseemployee awareness of sleep hygiene and tostimulate discussion about the types ofstrategies that could be implemented toincrease the chances of obtaining effectivesleep and promoting daytime alertness.


14

Health and sleep disorders

There are a multitude of medical causes ofsleep loss including pain, chronic cough,mental ill-health and sleep disorders.While theproportion of accidents related to healthcomplaints is not known, sleep disorders canlead to a significant increase in accident risk:one study found that the accident rate ofpeople with a sleep disorder was more than 13times higher than that of a control group.There are more than 80 medically-definedsleeping disorders: some of these disorders,e.g. insomnia, affect us all at one time oranother, while others are extremely rare.Thissection provides information on some of themore common sleep disorders.

Obstructive sleep apnœa (OSA)

Obstructive sleep apnœa (OSA) is a sleepdisorder associated with obstruction of theairway in the throat. Complete obstructioncan last from a few seconds to up to 30seconds and may occur many times an hour.Each closure of the airway results in hypoxia(oxygen deficiency) which causes the suffererto awaken momentarily to re-open the airway.OSA is always accompanied by loud snoringand sometimes by gasping or choking sounds.

As OSA causes repeated awakening it isinevitably associated with poor sleep quality,excessive fatigue and performance impairment.Research has shown that drivers suffering fromOSA are typically between 2 and 3 times morelikely to have road accidents than thosewithout the condition. As well as increasingthe risk of accident, OSA is a serious medicaldisorder which, if left untreated, increases therisk of heart disease, diabetes and stroke.

Who is at risk from OSA?As many as 4 per cent of men and 2 per cent ofwomen are thought to suffer from OSA. Thedisorder can affect anyone but is particularlycommon in middle-aged men; it is associatedwith obesity and large neck size.The majorityof people who suffer from OSA do not knowthat they have the disorder. People can sufferfrom the condition—undiagnosed—for manyyears, and be unaware of their debilitation.

If someone has OSA their sleeping partneris more likely than them to be aware of theloud snoring and respiratory pauses. A partnermay also note frequent awakenings, bodyjerking and gasping.

What treatments are available for OSA?The most effective treatment for OSA is touse a CPAP (Continuous Positive AirwayPressure) device when sleeping. A CPAPdevice consists of a mask that fits over thenose, and in rare cases over the mouth,connected via a plastic tube to a mini-aircompressor. The stream of air that flowsthrough the nose forces the airways to remainopen, thereby facilitating unobstructedbreathing and stopping snoring. The devicedoes not cure sleep apnœa, but when usedcorrectly and every night, this treatment cansubstantially reduce symptoms and reduce therisk for cardiovascular morbidity and mortality.

Unfortunately many people that try CPAPdo not use the device on an ongoing basis.The device can be inconvenient, cause nasal


15

congestion, claustrophobic sensations, andother side-effects. It is therefore important thatpeople using CPAP receive extensive educa-tion, attend regular follow-up appointmentsand receive the support that they need tomaintain treatment.

If an individual cannot use CPAP there aresurgical treatment options available, althoughthese are not as effective as CPAP. Thesurgical options include clearing nasal passagesand removal of the uvula along with removalof excess tissue in the palate and pharynx.Some people may benefit from wearing amandibular advancement device (a type ofgum shield) at night. The device holds thelower jaw and tongue forward and elevates thesoft palate to keep the airway open.

The severity of sleep apnœa can be reducedwith weight loss, avoidance of alcohol, sedativesand muscle relaxants, and by sleeping on theside (OSA is most severe when sleeping on theback). In mild cases of OSA these lifestyleadjustments may provide sufficient relief.

Insomnia

Insomnia is a disorder of too little or poor-quality sleep and usually takes one or more ofthe following forms:● Difficulty falling asleep—more common

among young people.● Sleeping lightly and restlessly, waking often,

lying awake in the middle of the night—more common in people over 40. Inyounger people it may be associated withdepression.

● Waking early and being unable to get backto sleep—this is more common in olderpeople and anyone worrying aboutsomething in particular.

Insomnia can be an acute problem, lastingfor a few nights or weeks, or may persist in thelong-term, lasting for several weeks, months oreven years. It can be caused by a range of

factors including stress, grief, job worries, acuteillness (fever, coughing, nasal obstruction, etc.),pre-existing medical, physical or psychologicalconditions as well as poor daytime and bedtimehabits. Prescribed medication as well as illicitdrug and alcohol use can provoke insomnia.

The solution to insomnia usually involvesfocusing on practicing good sleep hygiene (seethe countermeasures for fatigue described in thesection on ‘Shift work’) and addressing thesource of the problem. In cases of acuteinsomnia this may involve simply waiting forthe cause of the insomnia to pass. For long-term insomnia medication may be necessaryor attempts made to change attitudes tosleep—a psychologist or sleep specialist canassist with this process.

A short course (two weeks) of prescribedsleep medication, supervised by a doctor, canbe useful. As sleeping medication can havehangover effects (reduced alertness andimpaired performance the next day) it isimportant that a doctor advises on whetherthe individual can drive and what sort ofwork tasks are appropriate. Long-term use ofsleep medication is rarely helpful becausepeople become accustomed to the medicationand it loses its effectiveness. Paradoxically,stopping sleep medication can cause insomniaas a withdrawal symptom.

Periodic limb movements in sleep

Periodic limb movements in sleep (PLMS) is acondition characterized by twitching, jerkingor bending of the limbs (usually only the feetor toes) during sleep.The movements brieflywake the individual, although they will notremember this, and lead to poor quality sleep.PLMS movements are usually very small, forexample toe twitches, but can include kickingand flailing of the arms and legs.

Most people with PLMS are not aware thatthey have the disorder although some willcomplain that no matter how long they sleepthey still feel tired. Treatments for PLMSinclude iron supplements, behavioural orlifestyle changes (e.g. walking, stretching, yoga,massage) and, for severe cases, medication tocontrol symptoms.

Managing the risk of sleep disorders

To manage the risk of sleep disorders it isessential that employees and their partners areeducated to identify the signs of thesedisorders. Appendix 2 provides a copy of asimple scale called the Epworth SleepinessScale which can be used to determine anindividual’s level of daytime sleepiness. Thescale can be incorporated into employeescreening procedures and annual check-ups,and used to raise awareness of sleep disorders.

Appendix 3 includes a questionnaire thatcan provide an indication of whether someonemay be suffering from OSA. As well asmaking the questionnaire available at work itis a good idea to mail the questionnaire, plusadditional educational material on OSA, toemployees’ partners as they are the peoplewho are most likely to detect the symptomsof the disorder.

Anyone with a suspected sleep disordershould seek diagnosis and treatment from adoctor and, ideally, from a qualified sleepspecialist. Depending on their reported

symptoms they may require an overnight sleepstudy.This is a non-invasive monitoring pro-cedure that can be performed in hospital or athome, and simply involves recording a rangeof physiological variables, for example heartrate and brain activity, throughout the night.

If local certified sleep disorder centres areavailable, it is recommended that a list of thesebe provided to the employee. It is alsoimportant to develop ways of encouragingemployees, particularly those in safety-sensitivepositions, to voluntarily report and seekdiagnosis of any sleep disorder.


16

Health and sleep disorders

Medication


17

Illicit drugs such as marijuana, heroin,amphetamines and cocaine have obviousadverse consequences for health and safety.This section, however, focuses on prescribedmedications and those that are available overthe counter at the chemist, which can affectalertness—these are used much more widelythan illicit drugs.

Prescription medication

Medication can elevate fatigue in two ways—directly, by reducing alertness (e.g. sedatives)and indirectly, by disrupting sleep. Aside fromsleeping medications, prescription medicinesthat can have sedative effects includepainkillers, muscle relaxants and treatments forhigh blood pressure, anxiety and depression.Medications that can promote fatigue bydisturbing sleep include stimulants such astheophylline (a respiratory stimulant used totreat asthma) and treatments for epilepsy andpsychiatric disorders.

In addition to having an effect individually,many drugs and medicines can interact tocreate additional problems. Employees shouldbe advised to always tell their doctor andpharmacist what they do for a living, to makesure that the medication they are taking doesnot interfere with their responsibility to be fitfor work.

Over-the-counter (OTC) medication

Many of the treatments for colds, flu andhay-fever that you can buy at the chemistcontain one or more of a group of substancescalled ‘antihistamines’. As well as reducing arunny nose, sneezing, allergies, etc., someantihistamines have such a strong sedatingeffect that they are also sold, under differentnames, as night-time sleep aids. Takingantihistamines during the day can impair yourperformance at work and your ability to drivesafely. In fact, the drowsiness caused by these

antihistamines is so pronounced that an OTCtaken at night can have hangover effects thatlast into the next day.

The most common antihistamines liable tocause drowsiness are:● chlorpheniramine;● diphenhydramine;● promethazine; and● triprolidine.

If you need to remain alert, you shouldcheck the active ingredients of any OTCmedication to make sure these antihistaminesare not included. There will usually be analternative medication available that containsnewer antihistamines, developed specifically tohave less of a sedating effect.

Other OTC medications that can promotedrowsiness include sleeping aids, painkillersand travel sickness pills. Herbal remedies forsleep problems include camomile, valerianroot, hops, lavender and passion-flower(Passiflora). Herbal sleep aids are unlikely tocause as much of a sedating effect as theaforementioned antihistamines, but they arenot so rigorously tested and can havesignificant side-effects and drug interactions.

Before using any medication always readthe warning label and the information leaflet.If in any doubt consult your doctor or thepharmacist.

‘Jet lag’ is the term applied to the effect onthe body of crossing time zones. It is causedby the disruption of the body’s circadianrhythms.The effects of jet lag depend on thenumber of time zones crossed and are subjectto each individual’s susceptibility. Symptomscan include insomnia, disorientation, tiredness,irritability, as well as changes in eating,sleeping and bowel habits.

To limit jet lag avoid alcohol, caffeine andexcess food on flights. Ensure you are notdehydrated—drink plenty of water prior toand during a flight. The rule of thumb isthat recovery from jet lag takes 24 hours pertime zone crossed.You should avoid criticalmeetings on the first day after arrival andavoid driving, certainly long distances, for atleast a few days.

On business trips that only last a few daysyou are unlikely to adapt to your new timezone.When possible, it is therefore best to tryand maintain your home sleep/wake pattern.If you are staying in a new time zone for anextended period you can speed up the rate atwhich you adjust by trying to synchronizesleeping patterns and meal times to your newenvironment as soon as possible.


18

Jet lag

Resources and further reading


19

Canadian Lung Association: Sleep Apnœa webpagewebsite: www.lung.ca/diseases-maladies/apnea-apnee_e.php

Energy Institute, UK: Human Factors webpagewebsite: www.energyinst.org.uk/index.cfm?PageID=703

International Classification of Sleep Disorders (Philipps-Universität, Marburg, Germany)website: http://web.uni-marburg.de/sleep/enn/database/asdadefs/welcome.htm

National Institutes of Health, Bethesda, Maryland, USA: sleep disorderswebsite: http://health.nih.gov/result.asp/601

National Sleep Foundation,Washington DC, USA website: www.sleepfoundation.org

Health and Safety Executive, United Kingdom. (2006). Managing Shift Work: Health and Safety Guidance.website: www.hse.gov.uk/humanfactors/shiftwork/index.htm

HSE Research Report No. 002, Psychosocial aspects of work and health in the North Sea oil and gas industry. 2002.ISBN 0 7176 2156 1.

HSE Research Report No. 318, Effect of shift schedule on offshore shift workers’ circadian rhythms and health. 2005.ISBN 0 7176 2973 2.

Baker, A. and Ferguson, S. (2004). Work Design, Fatigue and Sleep. A Resource Document for the Minerals Industry.Minerals Council of Australia. 2004.

Folkard, S. (1997). Black times: temporal determinants of transport safety. Accident Analyses and Prevention, 29, 417–430.

Johns, M.W. (1991). A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep, 14:540-5. 1991.

Kryger, M., Roth,T. and Dement,W. (2005). Principles and Practice of Sleep Medicine. Elsevier Saunders.

Mastin, D. F., Bryson, J. & Corwyn, R. (2006). Assessing sleep hygiene using the sleep hygiene index. Journal of Behavioral Medicine.

Monk,T. H. and Folkard, S. (1992). Making shift work tolerable.Taylor and Francis, London.

Rosekind, M.R., Gregory, K.B., Mallis, M.M. (2006). Alertness management in aviation operations: enhancing performanceand sleep. Aviation, Space and Environmental Medicine, 77:1256–65.

Thomas, M., Sing, H., Belenky, G., Holcomb, H., Mayberg, H., Dannals, R.,Wagner, H. Jr.,Thorne, D., Popp, K., Rowland, L.,Welsh, A., Balwinski, S. and Redmond, D. (2006). Neural basis of alertness and cognitive performance impairments duringsleepiness. I. Effects of 24 h of sleep deprivation on waking human regional brain activity. Journal of Sleep Research, 9 (4),335–352. 2006.


20

Appendix 1

Sleep hygiene

Ada

pted

fro

m:M

astin

et a

l.,20

06

I take daytime naps lasting two or more hours

I go to bed at different times from day to day

I get out of bed at different times from day to day

I exercise to the point of sweating within one hour of going to bed.

I stay in bed longer than I should two or three times a week

I use alcohol, tobacco, or caffeine within four hours of going to bed or after going to bed

I do something that may wake me up before bedtime (for example: play video games, use the internet, or clean)

I go to bed feeling stressed, angry, upset or nervous

I use my bed for things other than sleeping or intimate relations (for example: watching television, reading, eating or studying)

I sleep on an uncomfortable bed (for example: poor mattress or pillow, too many or too few blankets)

I sleep in an uncomfortable bedroom (for example: too bright, too stuffy, too hot, too cold or too noisy)

I do important work before bedtime (for example: pay bills or study)

I think, plan, or worry when I am in bed

Review the statements below to see which undesirable sleep-related behaviours may apply to you.

Sleep-related behaviours which may affect your ability either to get to sleep or remain asleep, or which can disturbthe quality of sleep


21

Appendix 2

The Epworth Sleepiness Scale: can you drive a vehicle safely?

How likely are you to doze off or fall asleep in the situations listed below, in contrast to feeling just fatigued? TheEpworth Sleepiness Scale is used in many countries and organizations to measure daytime sleepiness and predict thedegree of sleep deprivation and/or disturbance and one’s ability to drive a company vehicle or perform other taskswithout falling asleep. It is closely correlated to the polysomnography or sleep tests.

A self-test to determine whether you are getting enough sleep

The questions below refer to your usual way of life in recent times. Even if you have not done some of these things recently try toimagine how they would have affected you.

Use the following scale to choose the most appropriate number for each situation: 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of dozing

What is your chance of dozing in the following situations: Enter 0, 1, 2 or 3 (see scale above)

Sitting and reading

Watching TV

Sitting inactive in a public place (e.g. a theatre or a meeting)

As a passenger in a car for an hour without a break

Lying down to rest in the afternoon when circumstances permit

Sitting and talking to someone

Sitting quietly after a lunch without alcohol

In a car, while stopped for a few minutes in traffic

TOTAL SCORE:

INTERPRETING YOUR SCORE:

Score How important is your sleep debt and sleep problem?

0–5 Slight or none—you are getting enough sleep.

6–10 You are experiencing a moderate degree of sleepiness.

11–20 You are experiencing a high degree of sleepiness.

21–24 You are experiencing a very high degree of sleep loss.

If you score 10 or more on this test, you should consider whether you are obtaining adequate sleep, need to improveyour sleep hygiene and/or need to see a sleep specialist. These issues should be discussed with your personal physician.

Any score above 15 should lead to a medical consultation before being authorized to drive a company vehicle oroperate heavy machinery in the workplace.

John

s,M

.W.,

1991


22

Appendix 3

Do you suffer from obstructive sleep apnœa (OSA)?

The test below provides an indicator as to the likelihood that you might have OSA. The test is by no meansdefinitive and only a trained physician can make a formal diagnosis of OSA.

To take the test all you need to do is answer ‘Yes’ or ‘No’ to each question and then refer to the box at the bottomof the page. Ideally you should do the test with your bed partner as they can probably help you out with many ofthe answers.

A self-test to determine whether you suffer from obstructive sleep apnœa

INTERPRETING YOUR RESULTS:

If you answered ‘Yes’ to three or more questions it is recommended that you speak to your doctor as soon you can

about the possibility that you might be suffering from OSA.

1. Are you overweight? (Calculate your BMI using the tool provided in Appendix 4— if your BMI is higher than 30 answer ‘yes’ to this question.)

2. Do you snore loudly when sleeping?

3. Do you choke or gasp at night?

4. Have you been told that you hold your breath or stop breathing when you sleep?

5. Do you feel excessively tired and sleepy during the daytime?

6. Do you have restless sleep and frequently toss and turn at night?

7. When you wake up in the morning do your mouth and throat feel dry?

8. Do you suffer from high blood pressure?

9. Do you wake up at night, feeling your heart thumping, sometimes with an irregular beat?

10. Do you wake up perspiring heavily?

‘Yes’ or ‘No’ ?Answer ‘Yes’ or ‘No’, then refer to the box at the foot of the page:


23

Appendix 4

Are you obese?

Use the guide below to measure and interpret your body mass index.

Calculation and interpretation of body mass index (BMI)

The BMI is your weight in kilogrammes divided by the square of your height in metres:

BMI =weight in kgs.

height in metres x height in metres

INTERPRETING YOUR BMI:

BMI Interpretation

< 18 You are underweight.

20–25 You are in the normal weight range for your height.

25–30 You are overweight.

> 30 You are obese.

> 40 You have what is called ‘morbid’ obesity.

> 50 You are in the category of ‘super’ or ‘malignant’ obesity.

Example 1:

If your weight is 70 kg and your height is 1.75 metres, your BMI is calculated as follows:

BMI =70

= 22.851.75 x 1.75

Example 2:

If your weight is 100 kg and your height is 1.75 metres, your BMI is calculated as follows:

BMI =100

= 32.651.75 x 1.75

To determine your BMI using pounds and inches, multiply your weight in pounds by 704.5, then divide the result by yourheight in inches, and then divide that result by your height in inches a second time.

The OGP/IPIECA Membership

Company membersADNOCAgipKCOAmerada HessAnadarko Petroleum CorporationBG GroupBHP BillitonBPCairn EnergyChevronCNOOCConocoPhillipsDolphin Energy DONG ENIExxonMobilGaz de FranceGNPOCHellenic PetroleumHocolHunt Oil CompanyHydroJapan Oil, Gas & Metals NationalCorporation Kuwait Oil CompanyKuwait Petroleum CorporationMærsk Olie og GasMarathon OilNexenNOC LibyaOXYOMVPapuan Oil Search LtdPerenco Holdings LtdPersian LNGPetroCanada PetrobrasPetropars LtdPDVSAPEMEXPDOPetronasPetrotrin Premier OilPTT EP Qatar PetroleumRasGasRepsol YPFSaudi Aramco Shell International Exploration & Production SNH CameroonSonatrachStatoilTNK-BP Management TOTALTullow OilWintershallWoodside EnergyYemen LNG

Association and Associate membersAustralian Institute of PetroleumAmerican Petroleum InstituteARPELASSOMINERARIABaker Hughes Canadian Association of Petroleum Producers Canadian Petroleum Products InstituteCONCAWEEnergy Institute European Petroleum Industry AssociationHalliburtonInstitut Français du PétroleIADC IAGCIOOAM-I SWACONOGEPA OLF PAJSchlumberger South African Petroleum Industry Association UKOOAWEGWorld Petroleum Council

International Association of Oil & Gas Producers (OGP)

OGP represents the upstream oil and gas industry before international organizations

including the International Maritime Organization, the United Nations Environment

Programme (UNEP) Regional Seas Conventions and other groups under the UN

umbrella. At the regional level, OGP is the industry representative to the European

Commission and Parliament and the OSPAR Commission for the North East Atlantic.

Equally important is OGP’s role in promulgating best practices, particularly in the areas

of health, safety, the environment and social responsibility.

International Petroleum Industry Environmental Conservation Association (IPIECA)

The International Petroleum Industry Environmental Conservation Association was

founded in 1974 following the establishment of the United Nations Environment

Programme (UNEP). IPIECA provides one of the industry’s principal channels of

communication with the United Nations.

IPIECA is the single global association representing both the upstream and

downstream oil and gas industry on key global environmental and social issues. IPIECA’s

programme takes full account of international developments in these issues, serving as a

forum for discussion and cooperation involving industry and international organizations.

IPIECA’s aims are to develop and promote scientifically-sound, cost-effective,

practical, socially and economically acceptable solutions to global environmental and social

issues pertaining to the oil and gas industry. IPIECA is not a lobbying organization, but

provides a forum for encouraging continuous improvement of industry performance.

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