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Effect of Exercise on Total
and Intra-abdominal Body Fat
in Postmenopausal Women
A Randomized Controlled Trial
Context The increasing prevalence of obesity is a major public health concern. Physi-
cal activity may promote weight and body fat loss.
Objective To examine the effects of exercise on total and intra-abdominal body fat
overall and by level of exercise.
Design Randomized controlled trial conducted from 1997 to 2001.
Setting and Participants A total of 173 sedentary, overweight (body mass index
Ն24.0 and Ͼ33% body fat), postmenopausal women aged 50 to 75 years who were Intervention Participants were randomly assigned to an intervention consisting of
exercise facility and home-based moderate-intensity exercise (n=87) or a stretching
Main Outcome Measure Changes in body weight and waist and hip circumfer-
ences at 3 and 12 months; total body, intra-abdominal, and subcutaneous abdominal US adult population isoverweight or obese,1 and Results Twelve-month data were available for 168 women. Women in the exercise
group participated in moderate-intensity sports/recreational activity for a mean (SD) of 3.5 (1.2) d/wk for 176 (91) min/wk. Walking was the most frequently reportedactivity. Exercisers showed statistically significant differences from controls in baseline to 12-month changes in body weight (–1.4 kg; 95% confidence interval [CI], –2.5 to eases, including coronary heart disease,2 –0.3 kg), total body fat (–1.0%; 95% CI, –1.6% to –0.4%), intra-abdominal fat type 2 diabetes,3 hypertension,4 stroke,5 (–8.6 g/cm2; 95% CI, –17.8 to 0.9 g/cm2), and subcutaneous abdominal fat (–28.8 g/cm2; 95% CI, –47.5 to –10.0 g/cm2). A significant dose response for greater body fat loss was observed with increasing duration of exercise.
Conclusions Regular exercise such as brisk walking results in reduced body weight
and body fat among overweight and obese postmenopausal women.
of preventing weight gain and promot-ing maintenance of weight loss in over- Author Affiliations: Department of Epidemiology and
Public Health, Yale University School of Medicine, NewHaven, Conn (Dr Irwin); Cancer Prevention Research Program, Fred Hutchinson Cancer Research Center (Drs Yasui, Ulrich, Bowen, Rudolph, Potter, and McTiernan and Ms Aiello), and Departments of Epidemiology (DrsUlrich, Potter, and McTiernan) and Internal Medi- cine (Drs McTiernan, Rudolph, and Yukawa), Univer- sity of Washington, Seattle; and Department of In- ternal Medicine, Division of Geriatric Medicine,University of Colorado Health Sciences Center, Den- Corresponding Author and Reprints: Anne McTiernan,
MD, PhD, Fred Hutchinson Cancer Research Center,
1100 Fairview Ave N, MP-900, Seattle, WA 98109- 2003 American Medical Association. All rights reserved.
(Reprinted) JAMA, January 15, 2003—Vol 289, No. 3 323
EXERCISE AND BODY FAT IN POSTMENOPAUSAL WOMEN Participants
sis of diabetes and had fasting blood glu- physiologist at a facility (University of been published elsewhere.11 After a tele- intensity recreational activity and maxi- baseline clinic visits (a physical exami- assessment, and dual-energy x-rayabsorptiometry [DXA] and computedtomography [CT] scans). After fur- Figure 1. Recruitment of Participants Into the Physical Activity for Total Health Study
ther determining eligibility and studyinterest, we randomly assigned 173 tion (n = 87) or the control group
(n = 86) (FIGURE 1). Randomization
eration and group assignment wasplaced in a sealed envelope, which was Baseline and Follow-up Measures
We collected demographic and medi-
cal history information at baseline andat 3- and 12-month visits. We mea- months, and 12 months via a 120-item self-administered food frequency physical activity at baseline, 3 months,and 12 months among exercisers and during the past 3 months. For the ac-tivities performed, the women re- corded the number of days per weekand minutes per session. 324 JAMA, January 15, 2003—Vol 289, No. 3 (Reprinted)
2003 American Medical Association. All rights reserved.
EXERCISE AND BODY FAT IN POSTMENOPAUSAL WOMEN and maintain joint stability. A variety ing a lateral-view radiograph of the skel- creased every 2 minutes (eg, stage 2: 3.5 and with a slice thickness of 8 mm).
Measure of Exercise Adherence
and computing the circumscribed areas.
kept daily activity logs of all sports or recreational activities they performed.
Exercise Intervention
intensity exercise 5 d/wk for 12 months.
were taken in duplicate and averaged.
cilities and to exercise 2 d/wk at home.
intensity sports/recreational exercise).
at the facility if they chose). The train- Intervention Strategies
ized attention in facility classes; group ex- mill walking and stationary bicycling.
Statistical Analysis
curls, leg press, chest press, and seated 2003 American Medical Association. All rights reserved.
(Reprinted) JAMA, January 15, 2003—Vol 289, No. 3 325
EXERCISE AND BODY FAT IN POSTMENOPAUSAL WOMEN Table 1. Baseline Characteristics of Randomized Participants in the Physical Activity for Total
control groups were similar (TABLE 1).
Exercisers
Controls
different activities (TABLE 2). Heart rate
ercise intervention (all after 3 months); Subcutaneous abdominal body fat, g/cm2 (CT) Total energy intake, mean (95% CI), kcal/d‡ Maximal oxygen consumption, mean (95% CI), Abbreviations: CI, confidence interval; CT, computed tomography; DXA, dual-energy x-ray absorptiometry.
*None of the comparisons between baseline characteristics of intervention and control participants were statistically †Body mass index is calculated as weight in kilograms divided by the square of height in meters.
‡Calculated from food frequency questionnaire.
baseline in body composition for both
groups are shown in TABLE 3. After 12
months, exercisers lost an average of 1.3 in controls (P=.01). The exercise group trol group (P = .045). Statistically sig- ues in the intent-to-treat analysis.
body weight (P=.05), BMI (P=.04), and hip circumference (P = .01) occurred over time (PϽ.05 for trend), with served at 12 months than at 3 months.
control participants, stratified by age and BMI at baseline, is shown in TABLE 4.
12 months did not vary by age or BMI.
326 JAMA, January 15, 2003—Vol 289, No. 3 (Reprinted)
2003 American Medical Association. All rights reserved.
EXERCISE AND BODY FAT IN POSTMENOPAUSAL WOMEN and stratified by tertiles of duration and level, are shown in FIGURE 2. Women
who exercised for more than 195min/wk (highly active) lost 4.2% of totalbody fat compared with losses of 2.4% Table 2. Types of Physical Activity Recorded Among Exercisers (n = 87) in Daily Activity Logs
Maximum Heart Rate %,
Activity Type
Observations, No. (%)
Mean (SD) [Range]*
At the Facility
level, is shown in FIGURE 3. Women
*Maximum heart rate percentage = (maximum heart rate max from graded exercise test − exercise heart rate)/ †Strength training included leg press, leg extension, leg curls, bench press, and seated dumbbell row.
‡Calisthenics included conditioning and floor exercises.
§Other activities were performed at a frequency of less than 0.1%.
Table 3. Change in Body Composition Measures at 3 and 12 Months in Exercise Intervention and Control Participants
Mean (95% Confidence Interval)
P
Value for
P
Baseline vs 3 mo
Baseline vs 12 mo
Difference Value
Exercisers
Controls
Difference
Exercisers
Controls
Difference
Baseline Trend*
−155 (−250 to −60) −151 (−246 to −55) Abbreviations: CT, computed tomography; DXA, dual-energy x-ray absorptiometry; NA, not applicable.
*Test for trend in between-group differences over time (ie, baseline vs 3 and 12 months).
†Body mass index is calculated as weight in kilograms divided by the square of height in meters.
‡Calculated from food frequency questionnaire.
2003 American Medical Association. All rights reserved.
(Reprinted) JAMA, January 15, 2003—Vol 289, No. 3 327
EXERCISE AND BODY FAT IN POSTMENOPAUSAL WOMEN in prolonged and increasing benefits.
tistically significant between-group dif- Table 4. Change in Body Composition Measures at 12 Months in Exercise Intervention Participants Stratified by Age and Body Mass Index at
Baseline
Mean (95% Confidence Interval)
Baseline
Baseline vs 12 mo
P Value for
Exercisers
Exercisers
Controls
Exercisers
Controls
Difference
vs Controls
Age at Baseline, y*
140.7 (121.9 to 159.6) 142.4 (123.8 to 161.0) 157.8 (133.3 to 182.2) 161.9 (142.6 to 181.3) −19.0 (−31.1 to −6.9) 149.6 (112.8 to 186.4) 132.3 (102.1 to 162.5) 401.4 (359.1 to 443.7) 366.3 (335.6 to 397.1) −12.3 (−26.3 to 1.7) 380.5 (338.8 to 422.1) 398.6 (336.0 to 461.2) −33.3 (−64.4 to −2.3) 366.8 (312.1 to 421.5) 321.9 (257.7 to 386.1) −28.0 (−66.1 to 10.0) Body Mass Index at Baseline†
117.5 (100.1 to 134.8) 135.4 (114.7 to 156.2) 179.1 (160.9 to 197.3) 171.9 (152.5 to 190.3) −10.4 (−21.6 to 0.8) 300.9 (266.3 to 335.4) 278.4 (237.1 to 319.8) −16.6 (−31.9 to −1.3) 347.1 (304.4 to 389.8) 339.4 (311.0 to 367.7) −30.7 (−54.8 to −6.6) 456.5 (421.0 to 492.0) 433.3 (389.5 to 477.1) −19.0 (−42.5 to −4.5) Abbreviations: CT, computed tomography; DXA, dual-energy x-ray absortiometry.
*Sample sizes for ages 50 to 59 years, 60 to 69 years, and 70 to 75 years, respectively: exercisers = 47, 27, and 13; controls = 45, 29, and 12.
†Body mass index is calculated as weight in kilograms divided by the square of height in meters. Sample sizes for body mass indexes of 24.1 to 27.5, 27.6 to 29.9, and 30.0 to 42.0, respectively: exercisers = 24, 21, and 42; controls = 19, 26, and 41.
328 JAMA, January 15, 2003—Vol 289, No. 3 (Reprinted)
2003 American Medical Association. All rights reserved.
EXERCISE AND BODY FAT IN POSTMENOPAUSAL WOMEN Figure 2. Percentage Change in Total Body
to sustain this loss over the long term.31 Fat at 12 Months by Tertile of Duration and greater loss of intra-abdominal fat among cise on intra-abdominal fat are needed.
vascular disease.21-25 Exercise may coun- teract the aberrant metabolic profile as- cise performed at the facility, which was Body fat was measured by dual-energy x-ray absorp- tiometry. Error bars indicate 95% confidence inter- pared to make the necessary changes.
vals; duration, minutes per week spent in moderate- intensity sports activity (low-active, Յ135 min/wk;intermediately active, 136-195 min/wk; and highly ac- tive, Ͼ195 min/wk); change in fitness, low-active, Յ5%; intermediately active, 5.1%-16%; and highlyactive, Ͼ16%; asterisk, significant difference com- pared with controls (PϽ.05); and dagger, significant difference compared with low-active group (PϽ.05).
Figure 3. Percentage Change in
by Tertile of Duration and Changein Fitness Level significantly greater weight and fat loss trolled trial of a moderate-intensity exer- Intra-abdominal body fat was measured by com- puted tomography. Error bars indicate 95% confi- dence intervals; duration, minutes per week spent in moderate-intensity sports activity (low-active, Յ135min/wk; intermediately active, 136-195 min/wk; and highly active, Ͼ195 min/wk); change in fitness, low- active, Յ5%; intermediately active, 5.1%-16%; andhighly active, Ͼ16%; asterisk, significant difference compared with controls (PϽ.05); and dagger, signifi- cant difference compared with low-active group(PϽ.05).
of exercise is similar to current national 2003 American Medical Association. All rights reserved.
(Reprinted) JAMA, January 15, 2003—Vol 289, No. 3 329
EXERCISE AND BODY FAT IN POSTMENOPAUSAL WOMEN Critical revision of the manuscript for important in- tellectual content: Irwin, Yasui, Ulrich, Bowen, Rudolph,Schwartz, Yukawa, Aiello, Potter, McTiernan.
Statistical expertise: Yasui.
Obtained funding: Schwartz, McTiernan.
Administrative, technical, or material support: Irwin, cardiorespiratory fitness. High levels of body fat, especially intra-abdominal fat.
Schwartz, Yukawa, Potter, McTiernan.
cardiorespiratory fitness reduce the rate Study supervision: Irwin, Bowen, Rudolph, Schwartz,Potter, McTiernan.
Author Contributions: Dr McTiernan, as principal
Funding/Support: This study was supported by re-
investigator of this study, had full access to all of search grant RO1-69334 from the National Cancer the data in the study and takes responsibility for Institute. Dr Irwin was also supported by a National the integrity of the data and the accuracy of the data Cancer Institute Cancer Prevention Training grant (T32 CA09661). A portion of this work was conducted Study concept and design: Irwin, Yasui, Ulrich, Bowen, through the University of Washington Clinical Re- search Center Facility and was supported by National Acquisition of data: Irwin, Ulrich, Rudolph, Schwartz, Institutes of Health grants M01-RR-00037 and of the exercise intervention lessened over Analysis and interpretation of data: Irwin, Yasui, Ulrich, Acknowledgment: We are indebted to the partici-
Bowen, Rudolph, Schwartz, Aeillo, Potter, McTiernan.
pants in the Physical Activity for Total Health Study Drafting of the manuscript: Irwin, McTiernan.
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