Short Report

Effects of Daily Exercise on Blood Pressure, Plasma Glucose,and Obesity Measures in 55–64-Year-Old Obese Asian IndianMen: The Calcutta Longitudinal Study

ARNAB GHOSH*

Palli Charcha Kendra, Visva Bharati University, Santiniketan 731 236, West Bengal, India

ABSTRACT The present longitudinal study was undertaken to study the effect of briskwalking on blood pressure, plasma glucose, and obesity measures in 55–64-year-old obese AsianIndian men. A total of 45 obese (body mass index �25 kg/m2) men took part in the study. Theywere monitored for 20 weeks. Obesity measures, blood pressure, fasting plasma glucose (FPG),and 30 min of brisk walking were recorded for each participant. Brisk walking was defined as2 km of walking by 30 min with moderate sweating. A general linear model (GLM) repeated-measures analysis procedure with Scheffe’s post hoc test revealed that group I (up to 5 weeks ofexercise) had significantly greater means compared to groups II (6–10 weeks), III (11–15 weeks),and IV (16–20 weeks) for body mass index (P < 0.01), waist-hip ratio (P < 0.001), percent bodyfat (P < 0.05), systolic blood pressure (P < 0.001), diastolic blood pressure (P < 0.001), and FPG(P < 0.001), whereas group I had a significantly lower mean than groups II, III, and IV for fre-quency of brisk walking (P < 0.01). It was also observed that change in D blood pressure andD FPG had a significant positive association with D obesity measures, independent of age effect.Therefore, brisk walking is recommended to lower blood pressure, blood glucose, and obesity(particularly central obesity) in middle-aged obese individuals. Am. J. Hum. Biol. 18:718–721, 2006.' 2006Wiley-Liss, Inc.

Obesity is unquestionably a chronic disorderthat causes considerable personal suffering. Itis now a problem not restricted to any particu-lar country or continent. Rather, both devel-oped and developing countries are experienc-ing this difficulty (Bouchard, 2000). Changinglifestyles, including dietary-habit changes anddecreased physical activity, are invariablyassociated with globalization and/or modern-ization (Ghosh and Das Chaudhuri, 2005).Previous studies suggest that brisk walkinghas beneficial physiological effects on lipid me-tabolism, glucose level, insulin action, andblood pressure in obese individuals (Morrisand Hardman, 1997; Miyatake et al., 2003).Habitual exercise is thus recommended as asupplementary form of therapy, along with di-etary treatment for obese subjects (Oshidaet al., 1989). Physical exercise by means ofbrisk walking was shown to improve cardior-espiratory fitness and cardiovascular healthin middle-aged and elderly individuals (Woolf-May et al., 1998; Paillard et al., 2002; Ghoshand Das Chaudhuri, 2005).

In India, chronic disease contributed to anestimated 53% of deaths and 44% of disability-adjusted life years (DALYs) lost in 2005 alone,with cardiovascular disease (CVD) and diabe-tes highly prevalent in urban areas (Reddyet al., 2005). Most importantly, in Asian popu-lations, mortality and morbidity from CVDare occurring in people with a lower bodymass index (BMI). Thus, these people tend toaccumulate intra-abdominal visceral fat with-out developing generalized obesity (WorldHealth Organization/International Associationfor the Study of Obesity/International ObesityTask Force (WHO/IASO/IOTF), 2000).

In view of the above considerations, thepresent longitudinal study, which to the bestof the author’s knowledge is the first of its

*Correspondence to: Dr. Arnab Ghosh, Palli CharchaKendra, Visva Bharati University, Santiniketan 731 236,West Bengal, India. E-mail: arnab_cu@rediffmail.com

Received 27 January 2006; Revision received 1 April2006; Accepted 3 April 2006

Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ajhb.20545

AMERICAN JOURNAL OF HUMAN BIOLOGY 18:718–721 (2006)

VVC 2006 Wiley-Liss, Inc.

kind in any Asian Indian population, wasundertaken to study the effects of daily exer-cise by means of brisk walking on blood pres-sure, plasma glucose, and obesity measures in55–64-year-old obese Asian Indian men.

SUBJECTS AND METHODS

Study population

The present study was conducted betweenMarch–October 2005. A total of 45 obese men,aged 55–64 years, took part in the study. Theywere recruited from a ‘‘Health Promotion Pro-gramme’’ initiated to study cardiovascularhealth. All participants were occupants of Cal-cutta or its suburbs, and were monitored for20 weeks. Informed consent was obtained fromall participants prior to commencement of thestudy. The Institutional Ethics Committee ofVisva Bharati University approved the study.

Anthropometric measures

Height, weight, and circumferences of thewaist (WC) and hip were recorded usingstandard techniques (Lohman et al., 1988) bythe author. Height and weight were measuredto the nearest 0.1 cm and 0.5 kg, respectively.Waist and hip circumferences were measuredwith an inelastic tape to the nearest 0.2 cm.Body mass index (BMI, in kg/m2) and waist-hip ratio (WHR) were computed accordingly.Percent body fat (PBF) was estimated fromskinfolds at four sites (biceps, triceps, sub-scapular, and suprailiac), using the equationof Durnin and Womersley (1974), as previouslyvalidated in Asian Indians (Kuriyan et al., 1998).

Cutoff values and exclusion criteria

Obesity was defined as BMI �25 kg/m2, fol-lowing the guidelines prepared exclusively forSouth Asian populations (World Health Orga-nization/International Association for theStudy of Obesity/International Obesity TaskForce (WHO/IASO/IOTF), 2000). Participantswith diagnosed type 2 diabetes or who werereceiving any hyperglycemic drug or insulintherapy were excluded from the study. No sub-jects were receiving any medications for diabe-tes and/or hypertension throughout the obser-vation periods.

Physiological variables

Two forenoon blood-pressure measurementswere taken and averaged for analysis. A third

measurement was taken only when the differ-ence between the two measurements wasgreater than 5 mm Hg, and the average wascalculated. Fasting plasma glucose (FPG) wasmeasured after an overnight fast of more than10 hr on venous blood, using an autoanalyzerin mg/dl (mg %) units.

Brisk walking program

Daily exercise by means of brisk walkingwas recorded throughout the observation pe-riod. Brisk walking was defined as 30 min ofwalking at a stretch with moderate sweating.Participants were requested to cover (point-to-point distance was estimated prior to actualcommencement of the study using a speedom-eter) 2 km by 30 min, a feasible alternative tomaintaining their speed during the walkingexercise. They were also instructed not to domore than the limit, to avoid any confusion forboth the subjects and the investigator.

Time and change in measures

It is noteworthy that all measures weretaken on the last weekday of the interval. Fur-thermore, changes in physiological variablesand fat measures were estimated as the differ-ence between baseline and final measures.

Statistical analyses

Comparison of physiological and obesitymeasures by weeks of exercise program wascomputed using a general linear model (GLM)repeated measures analysis procedure withScheffe’s post hoc test. Pearson’s partial corre-lation (controlling for the cubic and quadraticeffects of age) between changes in physiologi-cal variables and obesity measures was alsoundertaken to see any linearity for changes intwo sets of variables (physiological vs. obesitymeasures). All statistical analyses were per-formed using the Statistical Package for SocialSciences (SPSS, version 10). Statistical signifi-cance (two-tailed) was set at P < 0.05.

RESULTS

The baseline means and standard devia-tions (SD) for obesity measures, physiologicalvariables, and frequency of brisk walking aregiven in Table 1. The mean age (in years) was60.4 6 6.2, with average BMI, WHR, and FPGrecorded as 26.3 6 1.2 kg/m2, 0.95 6 0.02, and112.4 6 12.0, respectively. To study the effectof daily exercise on physiological and obesity

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measures, the 20-week observation period wasdivided into four groups: group I (up to 5weeks), group II (6–10 weeks), group III (11–15 weeks), and group IV (16–20 weeks). Com-parison of the four groups was undertakenusing a GLM repeated-measure analysis pro-cedure with Scheffe’s post hoc test, as shownin Table 1. The results reveal that group I hadsignificantly greater means compared togroups II, III, and IV for BMI (P < 0.01), WHR(P < 0.001), PBF (P < 0.05), systolic bloodpressure (SBP) (P < 0.001), diastolic bloodpressure (DBP) (P < 0.001), and FPG (P <0.001), whereas group I had significantlylower mean than groups II, III, and IV for fre-quency of brisk walking (P < 0.01). Age-con-trolled (adjusted for cubic and quadraticeffects of age) partial correlations betweenchanges in blood pressure measures (D SBPand D DBP) and FPG (D FPG) with changes inobesity measures (D BMI, D WHR, and D PBF)were also undertaken, as shown in Table 2.The results reveal that D BP and D FPG had asignificant positive association with D obesitymeasures, independent of age effect. In fact,the association was more pronounced (P <0.001) for central obesity measures (i.e., WHR)compared to BMI or PBF.

DISCUSSION

This study reports on the effects of dailyexercise by means of brisk walking on bloodpressure and plasma glucose levels in a 20-week longitudinal study on obese individualsof Asian Indian origin. Both blood pressureand blood glucose are considered important in-

dependent risk factors for mortality and mor-bidity from CVD. No study similar to the pres-ent one has been undertaken on middle-agedAsian Indians to follow the effective changesin CVD risk factors owing to daily exercise bymeans of brisk walking.

The literature reveals that an exercise pro-gram including swimming, cycling, jogging,etc., has significant CVD risk factor-loweringeffects in middle-aged individuals (Seals et al.,1997; Guo et al., 1999; Paillard et al., 2002).The present longitudinal trial also demon-strated that increased brisk walking (1.6 vs. 5days in a week) had a significant positiveimpact on lowering both SBP (152.0 6 11.6 vs.142.2 6 10.5, mean 6 SD) and DBP (90.2 6 9.8vs. 86.4 6 10.0, mean 6 SD) in 55–64-year-oldindividuals. Increased brisk walking was alsoshown to significantly decrease FPG (110.2 611.2 vs. 98.8 6 8.4, mean 6 SD) after complet-ing 20 weeks of a brisk walking program. Mostimportantly, both physiological variables (i.e.,blood pressure and fasting glucose) had de-creased, independent of age effect. Furthermore,there was a significant decrease in mean values

TABLE 1. Comparison of physiological and obesity measures by weeks of exercise

VariableBaselinemean (SD)

Weeks of exercise

Up to5 weeks 6–10 11–15 16–20

Age (years) 60.4 (6.2)BMI**1 26.3 (1.2) 26.0 6 1.1 25.86 1.0 25.46 1.3 24.86 1.2WHR***1 0.95 (0.02) 0.94 6 0.01 0.916 0.02 0.906 0.03 0.886 0.04PBF*1 34.4 (4.2) 34.0 6 3.2 32.86 2.8 31.26 2.6 30.16 2.6SBP***1 152.4 (12.6) 152.0 6 11.6 150.0 6 11.4 148.4 6 12.6 142.2 6 10.5DBP***1 90.5 (10.2) 90.2 6 9.8 89.46 10.1 88.26 9.5 86.46 10.0FPG***1 112.4 (12.0) 110.2 6 11.2 107.2 6 9.8 102.2 6 10.1 98.86 8.4Frequency**of brisk walking(days/week)2

1.6 (0.60) 2.4 6 0.56 3.66 0.74 4.26 0.48 4.86 0.52

1Group I (up to 5 weeks) had significantly greater mean compared to groups II (6–10 weeks), III (11–15 weeks), and IV (16–20 weeks)for BMI, WHR, PBF, SBP, DBP, and FPG (Scheffe post hoc test).2Group I had significantly lower mean compared to groups II, III, and IV (Scheffe post hoc test).*Significant group differences at P < 0.05.**Significant group differences at P < 0.01.***Significant group differences at P < 0.001.

TABLE 2. Partial correlations (controlling for cubicand quadratic effects of age) between changes inphysiological variables and obesity measures

Variable D SBP D DBP D FPG

D BMI 0.41** 0.47** 0.32*D WHR 0.61*** 0.67*** 0.66***D PBF 0.31 0.33* 0.41**

*Significant at P < 0.05.**Significant at P < 0.01.***Significant at P < 0.001.

720 A. GHOSH

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of BMI, WHR, and PBF from group I (up to 5weeks of exercise) to group IV (16–20 weeks ofexercise), and changes were more profound forWHR (P < 0.001) compared to BMI (P < 0.01)and PBF (P < 0.05). This is critically importantfor people of Asian Indian origin, in whom CVDoccurs with lower BMI and PBF with higher cen-tral obesity (e.g., WHR) compared to Caucasianor American populations (Ghosh et al., 2003).However, this study’s major limitation is

that it was performed on a small sample size,and therefore is not representative of theAsian Indian population. Owing to the vastethnic and cultural heterogeneity in the AsianIndian population, it is imperative to studyother ethnic groups to see if the trendsobserved here also exist among them. Resultsobtained from such studies could be utilized torecommend a general daily exercise level inthis population. However, to best of theauthor’s knowledge, no real attempt in thisregard has been attempted for the Indian sub-continent.

CONCLUSIONS

It seems reasonable to argue that a 30-minbrisk walk at least 5 days a week should be re-commended to lower blood pressure, plasmaglucose, and obesity (particularly central or vis-ceral obesity) in middle-aged obese individuals.

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American Journal of Human Biology DOI 10.1002/ajhb