chapter 03 measurement and surveillance of physical activity and fitness

Chapter 03

Measurement and Surveillance of Physical

Activity and Fitness

Measurement and Surveillance of Physical Activity and Fitness

• Behavioral Epidemiology-The observation and study of behaviors that lead to premature death and of the distribution of these behaviors.

IMPORTANT QUESTIONS:• What are the relationships between behavior

and disease ?• What are the determinants and distribution

of the behavior in the population ?

• If the behavior can be linked to the disease, then how can the behavior be altered to prevent, or contain, or cure disease? Thus, behavioral epidemiology the focus is to understand the behaviors that increase or decrease the risk of developing disease.


• Behavioral Epidemiology is used to observe, study, and change unhealthy behaviors. Physical inactivity has been observed, studied, and recommendations have been made to change the unhealthy behavior. Because physical (in) activity is a behavior, it is a focus of Behavioral Epidemiology.

• Physical Activity – “Any bodily movement produced by skeletal muscle that results in energy expenditure”. Physical activity is the most variable component of daily energy expenditure, thus activity becomes a behavioral choice for increasing or decreasing daily energy expenditure.

• Physical Activity Epidemiology– Compares levels of physical activity and disease or

injury risk


• Measures of Physical Activity (energy expenditure)

• Calorimetry• Doubly Labeled Water• Heart Rate Monitors• Motion Sensors• Physical Activity Questionnaires


• Measures of Physical Activity

• Calorimetry – Calories (unit of energy) can be measured by

using either direct or indirect colorimetry – Direct Calorimetry involves the measure of

heat production of an individual in a sealed, insulated chamber.

– Indirect Calorimetry involves estimating energy expenditure from oxygen consumption and carbon dioxide production.• Caloric equivalents = 5 kcal / 1 L O2



• Doubly Labeled Water (DLW) – Water that has isotopes of hydrogen and oxygen that diffuse into the fluid volume of the body. When the water is drunk, the two isotopes rapidly distribute in the body and start to be eliminated from the body.

– The hydrogen isotope measures water flux– The oxygen isotope measures the water and

carbon dioxide flux– The difference between the two is carbon

dioxide flux – Recall that measuring CO2 is indirect

colorimetry– Allows for energy expenditure to be measured

outside of the laboratory setting– Expensive cost of DLW and analysis equipment

make its use prohibitive for most epidemiology studies with large numbers of subjects



Heart Rate Monitors – Monitors that are strapped to the chest wall and store heart rate data that can be downloaded into computer programs for analysis. Monitors also display real time heart rates on a digital watch.

Monitors are used to measure indirect colorimetry because of the assumed linear association of heart rate to oxygen consumption. This association is often calculated via regression analysis, and there is no “perfect association” for any level of activity, only a predicted association. Thus validity of this association is questionable at various activity levels.



• Motion sensors• Motion sensors such as pedometers (counters)

have a history of poor validity and reliability of measure. Even the pedometers studied with high validity showed problems with interunit reliability.

• Accelerometers determine vertical displacement, and provide a measure of frequency and intensity of movement. Accelerometric measures have a higher correlation with energy expenditure than pedometers when examining walking and running activities. Mass use of accelerometers is still cost prohibitive in large epidemiology studies.



• Physical Activity Questionnaires– Physical activity questionnaires are the

most practical and often used method of assessing physical activity in epidemiologic studies. This format allows for the collection of physical activity information from large numbers of people in a time and cost efficient manner.

• Physical Activity Questionnaires

– Commonly Used Questionnaires• Minnesota Leisure Time Physical Activity

Questionnaire• Harvard Alumni Physical Activity Survey• Stanford Seven-Day Physical Activity Recall• International Physical Activity

Questionnaire (IPAQ)• Global Physical Activity Questionnaire (

GPAQ)• Community Health Activities Model

Program For Seniors (CHAMPS)• It is generally thought that individuals tend to

overestimate participation in vigorous activity and underestimate participation in light-to-moderate activities.

• Additional works needs to be done to enhance the recall of physical activity intensity on self-report measures.

https://sites.google.com/site/theipaq/

http://www.who.int/chp/steps/instrument/en/index.html

http://sbs.ucsf.edu/iha/champs/resources/qxn/


• Physical Fitness– Can be measured as an out come of

physical activity– Can be measured as a moderator on

morbidity and mortality– Physical fitness for purposes of health,

is best defined by the specific components that relate to improved health or reduced disease. The components of Health-Related Fitness are on Table 3.2, p.49, text. The major categories are: (see next slide)

– Morphological– Muscular– Motor– Cardiorespiratory– Metabolic

The Components of Health Related Fitness



• Physical Fitness – Morphological Component

– Variables• Body mass for height• Body composition• Subcutaneous fat distribution• Abdominal fat distribution• Bone Density• Flexibility


• Physical Fitness – Morphological Component– Measuring Body Fatness

• The relationship of body mass to fatness is most commonly expressed as Quetelet’s Body Mass Index (BMI)

– BMI = Body mass (kg) / Height ( m) 2 .– High BMI ( >25, men ; >30 women) is a risk

factor for all-cause mortality and increases the risk for hypertension, high triglycerides, high cholesterol, impaired glucose tolerance, and high insulin levels.

– BMI is a not a valid measure in athletic (large fat-free mass), pregnant, or frail elderly persons


• Measuring Body Fatness– Fat Patterning

• Android Pattern Obesity – Concentration of body fat predominately along the trunk (apple shape)

• Gynoid Pattern Obesity – Concentration of body fat predominately along the hips ( pear Shape)

• Android obesity is more prevalent in men, gynoid in women.

• Circumference measurements are taken at the level of the hip ( gluteus) and the waist (umbilicus), and waist-to –hip ratios are derived.

• Waist-to- hip rations ≤ 0.85 in women and ≤ 0.95 in men increase risk of metabolic disorders


– Bone Mass• Bone mass is measured via Dual X-ray

absorptiometry (DXA)• Osteoporosis results from accelerated bone

mass loss • Risk Factors

– Small Frame Caucasian Women (inherited susceptibility)

– Amenorrhea– Low dietary calcium– Post menopause– Physical Inactivity– ** Negative Risk = Increased lean mass


– Flexibility• Defined as the range of motion of a specific

joint during both passive and dynamic movement

• Flexibility is joint specific• The loss or gain if flexibility is very specific

to each joint• As a measure of physical fitness, flexibility

is usually distinguished from the laxity of a joint, which is a measure of joint instability governed largely by the tightness of ligaments.


• Muscular Component

– Muscular Strength /Muscular Endurance• Muscle Mass typically decreases as a

function of aging• Increase in fat mass often accompanies the

decrease in muscle mass• Loss of muscular fitness decreases mobility,

strength, and endurance needed for Activities of Daily Living (ADL)

• Maintaining muscular fitness in the trunk mayu reduce the risk for low back pain


• Motor Component

– Motor Fitness is determined by speed of movement, agility, balance, and coordination

– Poor coordination and balance increases the risk of falls and fractures aged adults

– Low motor fitness in childhood may have a long-lasting impact, contributing indirectly to sedentary living among adults who did not develop the psychomotor skills needed for many leisure physical activities.


• Cardiorespiratory Component– Considered a major component of

physical fitness in the prevention of CHD.

– Subcomponents include:• Maximal Aerobic Capacity• Submaximal Exercise Capacity• Cardiac Function• Pulmonary Function• Blood Pressure


Subcomponents :• Maximal Aerobic Capacity

– Maximal oxygen uptake measured in both absolute and relative terms. Absolute measures = ( L/min or ml/min ); Relative ( ml/kg-1/min-1

– Measured during a maximal aerobic test when fatigue occurs

• Submaximal Exercise Capacity– The ability to sustain an intensity of power

output for a prolonged period of time that is below the maximum aerobic capacity

• Cardiac Function– Assessed by determining heart functions– Heart rate, ejection fraction, myocardial

shortening rate, cardiac output ( stroke volume times heart rate)


Subcomponents include:• Pulmonary Function

– Lung Functions have both static and dynamic volumes (see details in text)

– These volumes can be affected by Chronic Obstructive Pulmonary Diseases

• Blood Pressure– High blood pressure can occur in systolic and/or

diastolic pressures– High blood pressure is considered > 140/90

mmHg– Chronic high blood pressure increases the risk of

stroke, heart attack, sudden cardiac death, aneurisms, and other organ failures


• Metabolic Component– Metabolic fitness is the newest

component of fitness recognized by exercise physiologists and epidemiologists who study health. It appears especially useful for understanding the potential health benefits of physical activity for preventing diabetes and atherosclerosis, the disease process leading to CHD and stroke.

– Subcomponents include:• Glucose Tolerance• Blood Lipid and Cholesterol Profiles• Lipid Oxidation

– Subcomponents include:• Glucose Tolerance

– Regular exercise can be used to treat glucose intolerance in Type II diabetics.

– Effects of exercise include normalizing insulin and glucagon production by the liver, increasing insulin sensitivity by the exercising muscle, thus enhancing glucose uptake.

• Blood Lipid and Cholesterol Profiles– Exercise decreases total blood cholesterol,

increases HDL-Cholesterol, and decreases blood triglycerides.

• Lipid Oxidation– High lipid oxidation alters cholesterol

metabolism and reduces body fat to reduce risk of cardiovascular disease. Thus, chronic aerobic exercise spares glucose stores and uses more fat oxidation for fuel.


• Exercise Training– Exercise training can be described by

• F requency – How often ?• I ntensity – How hard?• T ime – How long ?• T ype – Mode of exercise

– Fitness Guidelines ( see Table 3.3, p. 53, text, and next slide)

Table 3.3 ACSM 1998 and 2008 Federal Physical Activity Guidelines for Americans


• F.I.T.T.– Frequency

• 3-5 times /week for improving fitness, most days of the week to improve health (improving fitness supposes an improvement in health)

– Intensity• 50-85% VO2 max ( and Heart Rate Reserve)

for cardiorespiratory fitness – Note new guidelines focus on METS

• 40% good start point for obese and sedentary

• 50-85% Rep Max with 8-15 reps, depending on age and desired muscular fitness outcome (muscle strength vs. endurance). Focus should be on major muscle groups

• With flexibility exercises, one should “feel” the stretch, but it should not be painful


– Time• 20-60 minutes(≥75 min/wk), longer

duration and lower intensity is effective on body fat loss

• Resistance exercises for each of the major muscle groups 2 or 3 days/week

– Type• Activities that involve:

– Large muscle groups– Repetitive activity– Continuous activity– Exercises involving balance, agility, and

coordination; and flexibility exercises for each of the major muscle–tendon groups (a total of 60 s /exercise) on ≥2days/week

Exercise Training

• Because body systems respond in very specific ways to the challenges imposed by different modes of exercise, a well-balanced exercise training program includes several modes. Certain types of physical activity that affect specific components of physical fitness might be especially effective in reducing the risk of specific diseases (table 3.4) – next slide


Table 3.4 - Dimensions of Physical Activity With Proposed Mechanism of Effect, Diseases

or Conditions Affected, and Potential Surveillance Definitions



• Dose Response of Physical Activity and Health

– Recall that establishing a dose response is one of the criteria for establishing causation

• Findings of Fact– An inverse relationship and a generally

linear relationship exists between physical activity and rates of all cause mortality and morbidity attributable to CVD and CHD incidence and mortality, and to Type II diabetes.

Table 3.5 Summary of Evidence for Dose–Response Effects of Physical

Activity on Adult Health



• Findings of Fact, continued…–Other health outcomes may have a

dose-response effect, however:• 1) in some areas not enough studies

examined the dose-response question• 2) measures of physical activity have

been imprecise• 3) some responses to physical activity

have been to small to study the dose influence

• 4) other confounding factors were not controlled


• Surveys and Surveillance of Physical Activity

– Surveys are used to determine the prevalence of physical activity in the population

– Trends in physical activity may be established by repeating the survey over the course of years. This action is called surveillance. Thus surveillance is necessary to measure secular trends in physical activity.


Table 3.7 Summary of U.S. Physical Activity Surveillance Data Sources


• Physical Activity Surveillance in the United States

• Geographic Variation

– Most active region = Rocky Mountain and Northwest; Least = Southeast

– States : Washington - 49% active; Washington D.C. – 19 % active (See Figure 3.11, text, see next slides)

Figure 3.11 Who’s physically active? percentages of adults in each state, the District of Columbia, and three U.S. territories meeting the healthy people 2010 recommendation for either regular vigorous physical activity (≥20 min per day on three or more days per week) or regular moderate activity (≥30 min per day on five or more days per week) in (a) 2005 and (b) 2007. Based on BRFSS 2008.



• Physical Activity Surveillance in the United States

• Population Subgroups– (see Figures 3.13-3.14, next slides)

• White males are the most active (girls become less active during adolescence)

• Physical activity decreases with age• Physical activity increases with education

level– In Class Discussion: “Physical Activity,

Fitness, and Aging” (p. 68-69)


Figure 3.13 Regular physical activity in the United States according to (a) gender and age, (b) race/ethnicity, and (c) education level. the dashed line indicates the national goal of 50%. Data from centers for Disease Control and Prevention, Health, United States, 2008. available: www.cdc.gov/nchs/hus/updatedtables.htm.


Figure 3.14 Physical inactivity in the United States according to (a) gender and age, (b) race/ethnicity, and (c) education level. the dashed line indicates the national goal of 20%.

Data from centers for Disease control and prevention, health, United States, 2008. available: www.cdc.gov/nchs/hus/updatedtables.htm


End of Presentation

chapter 03 measurement and surveillance of physical activity and fitness

Documents

physical activity epidemiology

levels of physical activity

physical inactivity

fitness slide

water dlw water

indirect calorimetry

epidemiology studies

injury risk slide