Effects of Crossed Leg on Blood Pressure

RUKIYE PINAR, NECMIYE SABUNCU AND AYSEGUL OKSAY

From the Marmara University College of Nursing, Istanbul, Turkey

Pinar R, Sabuncu N, Oksay A. Effects of crossed leg on blood pressure. Blood Pressure 2004; 13: 252–254.

It is known that many factors influence an individual’s blood pressure measurement. However, guidelinesfor accurately measuring blood pressure inconsistently specify that the patient should keep feet flat on thefloor. The purpose of this study was to examine the effects of a crossed leg position on blood pressure in aTurkish sample. A prospective study of 238 subjects with an unmedicated high-normal blood pressure,stage 1 or stage 2 hypertension was conducted. After obtaining informed consent, subjects positionedtheir feet flat on the floor while their blood pressure was being measured. After 3 min, the blood pressurewas measured again with the subject’s leg crossed at the knee. Mean values of blood pressure werecompared byt-test between two measurements. Statistical significance for all analysis was taken at the5% level. The results indicated that both systolic and diastolic blood pressure increased significantly withthe crossed leg position. Crossing the leg at the knee results in a significant increase in blood pressure.When blood pressure is measured, subjects should be instructed to have feet flat on the floor to eliminate apotential source of error.Key words: blood pressure, crossed leg, hypertension.

INTRODUCTION

The public as well as health practitioners are becomingincreasingly aware of the importance of having regularblood pressure (BP) measurements, because of the healthrisks associated with hypertension. Hypertension isamong the most common reasons for outpatient visits[1], and is a common, powerful and independent riskfactor for cardiovascular disease and stroke, as well asend-stage kidney disease [2–4]. Furthermore, this riskincreases with progressive elevations in BP, evenbeginning at normal levels of BP [2, 4]. Therefore,reduction of BP to optimal levels and control of hyper-tension remain major public health priorities [5].

The measurement of BP is an important part of routinenursing practice, and provides the criteria to detect and tofollow subjects under the risk of developing hypertension,initiate antihypertensive therapy if necessary and adjustrecommended life-style modification and medical anti-hypertensive therapy to manage hypertension. Althoughnot an acceptable practice, a single BP measurement isoften the basis for clinical decisions [6]. Thus, it is crucialto eliminate all possible sources of error in measuring aperson’s BP.

Factors which may influence both the precision andaccuracy of BP measurement include faulty equipment,improper cuff length or width, white-coat effect, anxiety,medications, caffeine consumption and smoking shortlybefore BP measurement, noise, extreme temperatures,constrictive clothing, and arm and body positions [7, 8].

Although BP can be measured when subjects are lying

or standing, clinical guidelines state that BP should bemeasured while patients are seated in a chair with backsupported, and arms bared and supported at the heart level[5]. Some guidelines for accurately measuring BP alsospecify that the person should keep feet flat on the floor[7, 9–11]. There is a theoretical basis for crossing legs toincrease BP [7]. However, guidelines for measurement ofBP are not consistent in recommending that patient’s legsshould not be crossed during measurement, since data arenot consistent regarding this question. The present studyaimed to determine if the leg crossed at the knee ascompared with feet flat on the floor affects BP measure-ment in a Turkish sample.

MATERIALS AND METHODS

Sample

This study was conducted at the outpatient hypertensionclinic at a University Hospital in Istanbul, betweenSeptember 2003 and December 2003. Approval for thestudy was obtained from the hospital administrationbefore the initiation of the study. To be eligible, subjectshad: 1) to be between 18 and 65 years of age; 2) to have anunmedicated high-normal BP, stage 1 or stage 2 hyper-tension (i.e. mean systolic BP of 130–179 mmHg and/ormean diastolic BP of 85–109 mmHg on three separateoccasions. The sample includes subjects with high-normal BP (130–139/85–89 mmHg) because subjects inthis group are also at risk of BP-related cardiovasculardisease morbidity and mortality [12]. Subjects wereexcluded from this study if they had a history of

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2004 Taylor & Francis on licence from Blood Pressure.ISSN 0803-7051DOI 10.1080/08037050410000903 BLOOD PRESSURE 2004

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peripheral vascular disease, lower extremities surgery oramputation, or any condition that would interfere withlower extremity positioning. Other exclusion criteria weresmoking and caffeine ingestion 30–60 min before BPmeasurement.

Two hundred and thirty-eight subjects met eligibilitycriteria. Informed verbal consent was obtained from allsubjects before their participation in the study.

Demographic data (age, sex) were obtained using aquestionnaire.

Measurement of BP

A trained nurse who did not know the aim of the studyperformed BP measurements. BP measurements weredone in a hospital’s education room, which was quiet andfree from temperature extremes.

We used a mercury-filled column sphygmomanometerto measure BP because we had excellent informationabout sources of variance. It is known that mercury-filledcolumn sphygmomanometer does not have to be recali-brated and is considered more accurate than the aneroidmanometer [13].

Prior to taking a BP reading, the subject wasencouraged to empty her or his bladder. The subjectwas seated in a chair with back supported, and instructedto place his or her feet flat on the floor. Each subject wasinstructed to remove constricting clothing (e.g. coats,sweaters, shirts). After having a rest for a minimum of5 min, the subject’s right arm was positioned comfortablyand supported on a table at the heart level, with the palmof the hand upward. The brachial artery was palpated, andthe appropriately sized cuff was placed on the subject’sright arm with the arrow directly over the brachial artery.An appropriate cuff size was determined from the mid-arm circumference of the subject. The BP monitor isequipped with a normal adult size cuff (24� 32 cm) andlarge adult size cuff (32� 42 cm) [14]. The subject wasinstructed to refrain from talking or moving during theprocedure. The BP was measured and recorded. After aminimum of 3 min, the subject was instructed to cross oneleg over the knee. Then the BP was measured again andrecorded.

Statistical analyses

Data were coded to the information form and transferred

to computer by independent staff. All data analyses wererun on SPSS, version 11.0. Data are presented as numbersand mean� standard deviation (SD), where appropriate.Mean values of BP at first and second measurement werecompared by t-test between the two measurements.Statistical significance for all analysis was taken at the5% level.

RESULTS

Baseline characteristics of participants

Assessments were obtained from 238 subjects. Mean�SD age of the group was 56.1� 8.7 years rangingbetween 25 and 83 years. The majority of subjects weremale (n = 138).

Table I displays the effects of crossed leg on BP, andshows the mean of differences that was reached bysubjects.

BP

Both systolic BP (SBP) and diastolic BP (DBP) increasedat leg-crossed position. From leg-uncrossed position toleg crossed position, mean� SD increases in SBP andDBP were 8.49� 7.57 and 5.71� 6.80 mmHg, respec-tively.

DISCUSSION

The physiological mechanism for the rise in BP with legcrossing is a translocation of blood volume from thedependent vascular beds to the thoracic compartment [7].Although there is a theoretical basis for crossing legs toincrease BP, there are controversial published dataaddressing this question.

Foster-Fitzpatrick and co-workers [7] demonstrated asignificant increase in BP taken with the leg crossed at theknee in 100 hypertensive men.

Keele-Smith & Price-Daniel [15] indicated that BP wassignificantly higher when legs were crossed vs uncrossedamong 110 subjects in a senior population.

In a study by Peteret al. [16], crossing legs during BPmeasurement significantly increased SBP and DBP inpatients who had hypertension. In healthy volunteers,SBP and DBP increased at legs crossed position but theeffect was non-significant on DBP. In the same study, itwas concluded that the cardiovascular risk class increased

Table I.Systolic and diastolic blood pressure (BP) measurement at leg uncrossed and crossed positions (n = 238)

Leg uncrossed,mean� SD

Leg crossed,mean� SD

Difference between two measurements,mean� SD t p

Systolic BP 145.12� 20.33 153.62� 20.20 8.49� 7.57 7.47 �0.001Diastolic BP 86.38� 10.81 92.10� 11.20 5.71� 6.80 9.16 �0.001

Effects of crossed leg on blood pressure 253

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for a large number of the hypertensive patients but less sofor the normatensive subjects.

In contrast to the studies above, Avvampato [17]showed no statistically significant difference in BPreadings of subjects with one leg crossed over the othervs both feet flat on the floor.

According to the results of this study, crossing the legduring standard BP measurement in 238 subjects signifi-cantly increased both SBP and DBP readings (p � 0.001).Our results are thus in agreement with findings from otherstudies [7, 15, 16].

Although guidelines for measurement of BP are notconsistent in recommending that a patient’s legs shouldnot be crossed during measurement, instructing patients tokeep feet flat on the floor during BP measurement is animportant nursing intervention that can contribute toaccurate measurements, interpretation and treatment ofhigh BP.

The major limitation of this study is the fact it was notrandomized in terms of BP assessments in the straight legand crossed leg position, respectively. We see this as aworthwhile goal for subsequent study.

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Submitted May 1, 2004; accepted July 7, 2004

Address for correspondence:

Rukiye Pınar, PhDTutuncu Mehmet Efendi CadKaptan Ihsan SkSeniha Apt, No: 6/1 GoztepeTR-80600 IstanbulTurkeyTel: �90 216 360 6326Fax:�90 216 330 3033E-mail: rukiyepinar@yahoo.com

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