Effects of a High vs Moderate Volume of Aerobic Exercise on Adiposity Outcomes in Postmenopausal Women: A Randomized Clinical Trial | Breast Cancer | JAMA Oncology | JAMA Network
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Canadian Society for Exercise Physiology. Canadian physical activity guidelines for adults 18-64 years. 2011. http://www.csep.ca/guidelines. Accessed May 24, 2015.
Haskell  WL, Lee  IM, Pate  RR,  et al; American College of Sports Medicine; American Heart Association.  Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association.  Circulation. 2007;116(9):1081-1093.PubMedGoogle ScholarCrossref
World Health Organization. Global recommendations on physical activity for health. 2011. Report No. 9789241599979. http://www.who.int/dietphysicalactivity/publications/9789241599979/en/. Accessed May 24, 2015.
Donnelly  JE, Blair  SN, Jakicic  JM, Manore  MM, Rankin  JW, Smith  BK; American College of Sports Medicine.  American College of Sports Medicine position stand: appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults.  Med Sci Sports Exerc. 2009;41(2):459-471.PubMedGoogle ScholarCrossref
Lau  DC, Douketis  JD, Morrison  KM, Hramiak  IM, Sharma  AM, Ur  E; Obesity Canada Clinical Practice Guidelines Expert Panel.  2006 Canadian clinical practice guidelines on the management and prevention of obesity in adults and children [summary].  CMAJ. 2007;176(8):S1-S13.PubMedGoogle ScholarCrossref
Moholdt  T, Wisløff  U, Lydersen  S, Nauman  J.  Current physical activity guidelines for health are insufficient to mitigate long-term weight gain: more data in the fitness versus fatness debate (the HUNT study, Norway).  Br J Sports Med. 2014;48(20):1489-1496.PubMedGoogle ScholarCrossref
Stehr  MD, von Lengerke  T.  Preventing weight gain through exercise and physical activity in the elderly: a systematic review.  Maturitas. 2012;72(1):13-22.PubMedGoogle ScholarCrossref
Richardson  CR, Newton  TL, Abraham  JJ, Sen  A, Jimbo  M, Swartz  AM.  A meta-analysis of pedometer-based walking interventions and weight loss.  Ann Fam Med. 2008;6(1):69-77.PubMedGoogle ScholarCrossref
Thorogood  A, Mottillo  S, Shimony  A,  et al.  Isolated aerobic exercise and weight loss: a systematic review and meta-analysis of randomized controlled trials.  Am J Med. 2011;124(8):747-755.PubMedGoogle ScholarCrossref
Donnelly  JE, Honas  JJ, Smith  BK,  et al.  Aerobic exercise alone results in clinically significant weight loss for men and women: Midwest Exercise Trial 2.  Obesity (Silver Spring). 2013;21(3):E219-E228.PubMedGoogle ScholarCrossref
Ross  R, Janssen  I.  Physical activity, total and regional obesity: dose-response considerations.  Med Sci Sports Exerc. 2001;33(6)(suppl):S521-S527.PubMedGoogle ScholarCrossref
Ross  R, Freeman  JA, Janssen  I.  Exercise alone is an effective strategy for reducing obesity and related comorbidities.  Exerc Sport Sci Rev. 2000;28(4):165-170.PubMedGoogle Scholar
Flegal  KM, Carroll  MD, Kit  BK, Ogden  CL.  Prevalence of obesity and trends in the distribution of body mass index among US adults, 1999-2010.  JAMA. 2012;307(5):491-497.PubMedGoogle ScholarCrossref
Lovejoy  JC, Champagne  CM, de Jonge  L, Xie  H, Smith  SR.  Increased visceral fat and decreased energy expenditure during the menopausal transition.  Int J Obes (Lond). 2008;32(6):949-958.PubMedGoogle ScholarCrossref
Toth  MJ, Tchernof  A, Sites  CK, Poehlman  ET.  Menopause-related changes in body fat distribution.  Ann N Y Acad Sci. 2000;904:502-506.PubMedGoogle ScholarCrossref
Franklin  RM, Ploutz-Snyder  L, Kanaley  JA.  Longitudinal changes in abdominal fat distribution with menopause.  Metabolism. 2009;58(3):311-315.PubMedGoogle ScholarCrossref
World Cancer Research Fund/American Institute for Cancer Research (AICR). Food, nutrition, physical activity, and the prevention of cancer: a global perspective. Washington, DC: AICR; 2007. http://www.dietandcancerreport.org/cancer_resource_center/second_expert_report.php. Accessed May 24, 2015.
World Cancer Research Fund/American Institute for Cancer Research (AICR). Continuous update project report: food, nutrition, physical activity, and the prevention of breast cancer. Washington, DC: AICR; 2010. http://www.dietandcancerreport.org/cancer_resource_center/second_expert_report.php. Accessed May 24, 2015.
Arnold  M, Pandeya  N, Byrnes  G,  et al.  Global burden of cancer attributable to high body-mass index in 2012: a population-based study.  Lancet Oncol. 2015;16(1):36-46.PubMedGoogle ScholarCrossref
Krishnan  K, Bassett  JK, MacInnis  RJ,  et al.  Associations between weight in early adulthood, change in weight, and breast cancer risk in postmenopausal women.  Cancer Epidemiol Biomarkers Prev. 2013;22(8):1409-1416.PubMedGoogle ScholarCrossref
Suzuki  R, Orsini  N, Saji  S, Key  TJ, Wolk  A.  Body weight and incidence of breast cancer defined by estrogen and progesterone receptor status—a meta-analysis.  Int J Cancer. 2009;124(3):698-712.PubMedGoogle ScholarCrossref
Hartz  A, He  T, Rimm  A.  Comparison of adiposity measures as risk factors in postmenopausal women.  J Clin Endocrinol Metab. 2012;97(1):227-233.PubMedGoogle ScholarCrossref
McTiernan  A.  Mechanisms linking physical activity with cancer.  Nat Rev Cancer. 2008;8(3):205-211.PubMedGoogle ScholarCrossref
Reichkendler  MH, Rosenkilde  M, Auerbach  PL,  et al.  Only minor additional metabolic health benefits of high as opposed to moderate dose physical exercise in young, moderately overweight men.  Obesity (Silver Spring). 2014;22(5):1220-1232.PubMedGoogle ScholarCrossref
Asikainen  TM, Miilunpalo  S, Kukkonen-Harjula  K,  et al.  Walking trials in postmenopausal women: effect of low doses of exercise and exercise fractionization on coronary risk factors.  Scand J Med Sci Sports. 2003;13(5):284-292.PubMedGoogle ScholarCrossref
Church  TS, Earnest  CP, Skinner  JS, Blair  SN.  Effects of different doses of physical activity on cardiorespiratory fitness among sedentary, overweight or obese postmenopausal women with elevated blood pressure: a randomized controlled trial.  JAMA. 2007;297(19):2081-2091.PubMedGoogle ScholarCrossref
Dalleck  LC, Allen  BA, Hanson  BA, Borresen  EC, Erickson  ME, De Lap  SL.  Dose-response relationship between moderate-intensity exercise duration and coronary heart disease risk factors in postmenopausal women.  J Womens Health (Larchmt). 2009;18(1):105-113.PubMedGoogle ScholarCrossref
Jakicic  JM, Marcus  BH, Gallagher  KI, Napolitano  M, Lang  W.  Effect of exercise duration and intensity on weight loss in overweight, sedentary women: a randomized trial.  JAMA. 2003;290(10):1323-1330.PubMedGoogle ScholarCrossref
Jakicic  JM, Otto  AD, Lang  W,  et al.  The effect of physical activity on 18-month weight change in overweight adults.  Obesity (Silver Spring). 2011;19(1):100-109.PubMedGoogle ScholarCrossref
Keller  CS, Robinson  B, Pickens  L.  Comparison of two walking frequencies in African American postmenopausal women.  ABNF J. 2004;15(1):3-9.PubMedGoogle Scholar
Rosenkilde  M, Auerbach  P, Reichkendler  MH, Ploug  T, Stallknecht  BM, Sjödin  A.  Body fat loss and compensatory mechanisms in response to different doses of aerobic exercise—a randomized controlled trial in overweight sedentary males.  Am J Physiol Regul Integr Comp Physiol. 2012;303(6):R571-R579.PubMedGoogle ScholarCrossref
Slentz  CA, Duscha  BD, Johnson  JL,  et al.  Effects of the amount of exercise on body weight, body composition, and measures of central obesity: STRRIDE—a randomized controlled study.  Arch Intern Med. 2004;164(1):31-39.PubMedGoogle ScholarCrossref
Ross  R, Hudson  R, Stotz  PJ, Lam  M.  Effects of exercise amount and intensity on abdominal obesity and glucose tolerance in obese adults: a randomized trial.  Ann Intern Med. 2015;162(5):325-334.PubMedGoogle ScholarCrossref
Asikainen  TM, Miilunpalo  S, Oja  P,  et al.  Randomised, controlled walking trials in postmenopausal women: the minimum dose to improve aerobic fitness?  Br J Sports Med. 2002;36(3):189-194.PubMedGoogle ScholarCrossref
Church  TS, Martin  CK, Thompson  AM, Earnest  CP, Mikus  CR, Blair  SN.  Changes in weight, waist circumference and compensatory responses with different doses of exercise among sedentary, overweight postmenopausal women.  PLoS One. 2009;4(2):e4515.PubMedGoogle ScholarCrossref
Friedenreich  CM, Woolcott  CG, McTiernan  A,  et al.  Adiposity changes after a 1-year aerobic exercise intervention among postmenopausal women: a randomized controlled trial.  Int J Obes (Lond). 2011;35(3):427-435.PubMedGoogle ScholarCrossref
Friedenreich  CM, MacLaughlin  S, Neilson  HK,  et al.  Study design and methods for the Breast Cancer and Exercise Trial in Alberta (BETA).  BMC Cancer. 2014;14(1):919.PubMedGoogle ScholarCrossref
R: a language and environment for statistical computing [computer program]. Version 2.11. Vienna, Austria: R Foundation for Statistical Computing; 2010.
Borg  G.  Borg's Perceived Exertion and Pain Scales. Champaign, IL: Human Kinetics; 1998.
Friedenreich  CM, Courneya  KS, Neilson  HK,  et al.  Reliability and validity of the Past Year Total Physical Activity Questionnaire.  Am J Epidemiol. 2006;163(10):959-970.PubMedGoogle ScholarCrossref
Csizmadi  I, Kahle  L, Ullman  R,  et al.  Adaptation and evaluation of the National Cancer Institute’s Diet History Questionnaire and nutrient database for Canadian populations.  Public Health Nutr. 2007;10(1):88-96.PubMedGoogle ScholarCrossref
Ainsworth  BE, Haskell  WL, Herrmann  SD,  et al.  2011 Compendium of physical activities: a second update of codes and MET values.  Med Sci Sports Exerc. 2011;43(8):1575-1581.PubMedGoogle ScholarCrossref
Ainsworth  BE, Haskell  WL, Leon  AS,  et al.  Compendium of physical activities: classification of energy costs of human physical activities.  Med Sci Sports Exerc. 1993;25(1):71-80.PubMedGoogle ScholarCrossref
Ainsworth  BE, Haskell  WL, Whitt  MC,  et al.  Compendium of physical activities: an update of activity codes and MET intensities.  Med Sci Sports Exerc. 2000;32(9)(suppl):S498-S504.PubMedGoogle ScholarCrossref
Diet*Calc Analysis Program [computer program]. Version 1.4.3. Bethesda, MD: National Cancer Institute Applied Research Program; 2005.
Pollock  ML, Foster  C, Schmidt  D, Hellman  C, Linnerud  AC, Ward  A.  Comparative analysis of physiologic responses to three different maximal graded exercise test protocols in healthy women.  Am Heart J. 1982;103(3):363-373.PubMedGoogle ScholarCrossref
Canadian Society for Exercise Physiology.  The Canadian Physical Activity, Fitness and Lifestyle Approach (CPAFLA): CSEP - Health and Fitness Program’s Health-Related Appraisal and Counselling Strategy.3rd ed. Supplement. Ottawa, ON: Canadian Society for Exercise Physiology; 2010.
National Institutes of Health.  Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults—the evidence report.  Obes Res. 1998;6(suppl 2):51S-209S.PubMedGoogle ScholarCrossref
Rosner  B.  Hypothesis Testing: Two-Sample Inference. Fundamentals of Biostatistics. 7th ed. Boston, MA: Brooks/Cole; 2011.
Foster-Schubert  KE, Alfano  CM, Duggan  CR,  et al.  Effect of diet and exercise, alone or combined, on weight and body composition in overweight-to-obese postmenopausal women.  Obesity (Silver Spring). 2012;20(8):1628-1638.PubMedGoogle ScholarCrossref
Velthuis  MJ, Schuit  AJ, Peeters  PHM, Monninkhof  EM.  Exercise program affects body composition but not weight in postmenopausal women.  Menopause. 2009;16(4):777-784.PubMedGoogle ScholarCrossref
Irwin  ML, Yasui  Y, Ulrich  CM,  et al.  Effect of exercise on total and intra-abdominal body fat in postmenopausal women: a randomized controlled trial.  JAMA. 2003;289(3):323-330.PubMedGoogle ScholarCrossref
Green  JS, Stanforth  PR, Rankinen  T,  et al.  The effects of exercise training on abdominal visceral fat, body composition, and indicators of the metabolic syndrome in postmenopausal women with and without estrogen replacement therapy: the HERITAGE family study.  Metabolism. 2004;53(9):1192-1196.PubMedGoogle ScholarCrossref
Exley  MA, Hand  L, O’Shea  D, Lynch  L.  Interplay between the immune system and adipose tissue in obesity.  J Endocrinol. 2014;223(2):R41-R48.PubMedGoogle ScholarCrossref
Greenberg  AS, Obin  MS.  Obesity and the role of adipose tissue in inflammation and metabolism.  Am J Clin Nutr. 2006;83(2):461S-465S.PubMedGoogle Scholar
Cleary  MP, Grossmann  ME.  Minireview: obesity and breast cancer: the estrogen connection.  Endocrinology. 2009;150(6):2537-2542.PubMedGoogle ScholarCrossref
Neilson  HK, Conroy  SM, Friedenreich  CM.  The influence of energetic factors on biomarkers of postmenopausal breast cancer risk.  Curr Nutr Rep. 2014;3:22-34.PubMedGoogle ScholarCrossref
Patterson  RE, Rock  CL, Kerr  J,  et al.  Metabolism and breast cancer risk: frontiers in research and practice.  J Acad Nutr Diet. 2013;113(2):288-296.PubMedGoogle ScholarCrossref
Rose  DP, Vona-Davis  L.  Biochemical and molecular mechanisms for the association between obesity, chronic inflammation, and breast cancer.  Biofactors. 2014;40(1):1-12.PubMedGoogle ScholarCrossref
Tworoger  SS, Zhang  X, Eliassen  AH,  et al.  Inclusion of endogenous hormone levels in risk prediction models of postmenopausal breast cancer.  J Clin Oncol. 2014;32(28):3111-3117.PubMedGoogle ScholarCrossref
Zhang  X, Tworoger  SS, Eliassen  AH, Hankinson  SE.  Postmenopausal plasma sex hormone levels and breast cancer risk over 20 years of follow-up.  Breast Cancer Res Treat. 2013;137(3):883-892.PubMedGoogle ScholarCrossref
Friedenreich  CM, Neilson  HK, Woolcott  CG,  et al.  Mediators and moderators of the effects of a year-long exercise intervention on endogenous sex hormones in postmenopausal women.  Cancer Causes Control. 2011;22(10):1365-1373.PubMedGoogle ScholarCrossref
Friedenreich  CM, Neilson  HK, Woolcott  CG,  et al.  Changes in insulin resistance indicators, IGFs, and adipokines in a year-long trial of aerobic exercise in postmenopausal women.  Endocr Relat Cancer. 2011;18(3):357-369.PubMedGoogle ScholarCrossref
Friedenreich  CM, Neilson  HK, Woolcott  CG,  et al.  Inflammatory marker changes in a yearlong randomized exercise intervention trial among postmenopausal women.  Cancer Prev Res (Phila). 2012;5(1):98-108.PubMedGoogle ScholarCrossref
Kay  SJ, Fiatarone Singh  MA.  The influence of physical activity on abdominal fat: a systematic review of the literature.  Obes Rev. 2006;7(2):183-200.PubMedGoogle ScholarCrossref
Vona-Davis  L, Howard-McNatt  M, Rose  DP.  Adiposity, type 2 diabetes and the metabolic syndrome in breast cancer.  Obes Rev. 2007;8(5):395-408.PubMedGoogle ScholarCrossref
Després  JP, Lemieux  I.  Abdominal obesity and metabolic syndrome.  Nature. 2006;444(7121):881-887.PubMedGoogle ScholarCrossref
Tchernof  A, Després  JP.  Pathophysiology of human visceral obesity: an update.  Physiol Rev. 2013;93(1):359-404.PubMedGoogle ScholarCrossref
Ahern  TP, Hankinson  SE, Willett  WC, Pollak  MN, Eliassen  AH, Tamimi  RM.  Plasma C-peptide, mammographic breast density, and risk of invasive breast cancer.  Cancer Epidemiol Biomarkers Prev. 2013;22(10):1786-1796.PubMedGoogle ScholarCrossref
Autier  P, Koechlin  A, Boniol  M,  et al.  Serum insulin and C-peptide concentration and breast cancer: a meta-analysis.  Cancer Causes Control. 2013;24(5):873-883.PubMedGoogle ScholarCrossref
Esposito  K, Chiodini  P, Capuano  A,  et al.  Metabolic syndrome and postmenopausal breast cancer: systematic review and meta-analysis.  Menopause. 2013;20(12):1301-1309.PubMedGoogle ScholarCrossref
Giannopoulou  I, Fernhall  B, Carhart  R,  et al.  Effects of diet and/or exercise on the adipocytokine and inflammatory cytokine levels of postmenopausal women with type 2 diabetes.  Metabolism. 2005;54(7):866-875.PubMedGoogle ScholarCrossref
Dutheil  F, Lac  G, Lesourd  B,  et al.  Different modalities of exercise to reduce visceral fat mass and cardiovascular risk in metabolic syndrome: the RESOLVE randomized trial.  Int J Cardiol. 2013;168(4):3634-3642.PubMedGoogle ScholarCrossref
Irving  BA, Davis  CK, Brock  DW,  et al.  Effect of exercise training intensity on abdominal visceral fat and body composition.  Med Sci Sports Exerc. 2008;40(11):1863-1872.PubMedGoogle ScholarCrossref
Ohkawara  K, Tanaka  S, Miyachi  M, Ishikawa-Takata  K, Tabata  I.  A dose-response relation between aerobic exercise and visceral fat reduction: systematic review of clinical trials.  Int J Obes (Lond). 2007;31(12):1786-1797.PubMedGoogle ScholarCrossref
Grundy  SM, Neeland  IJ, Turer  AT, Vega  GL.  Waist circumference as measure of abdominal fat compartments.  J Obes.2013;2013:454285.Google ScholarCrossref
Bergström  I, Lombardo  C, Brinck  J.  Physical training decreases waist circumference in postmenopausal borderline overweight women.  Acta Obstet Gynecol Scand. 2009;88(3):308-313.PubMedGoogle ScholarCrossref
Lee  JJ, Beretvas  SN, Freeland-Graves  JH.  Abdominal adiposity distribution in diabetic/prediabetic and nondiabetic populations: a meta-analysis.  J Obes.2014;2014:697264.Google ScholarCrossref
Wildman  RP, Janssen  I, Khan  UI,  et al.  Subcutaneous adipose tissue in relation to subclinical atherosclerosis and cardiometabolic risk factors in midlife women.  Am J Clin Nutr. 2011;93(4):719-726.PubMedGoogle ScholarCrossref
Goedecke  JH, Levitt  NS, Lambert  EV,  et al.  Differential effects of abdominal adipose tissue distribution on insulin sensitivity in black and white South African women.  Obesity (Silver Spring). 2009;17(8):1506-1512.PubMedGoogle ScholarCrossref
Vega  GL, Adams-Huet  B, Peshock  R, Willett  D, Shah  B, Grundy  SM.  Influence of body fat content and distribution on variation in metabolic risk.  J Clin Endocrinol Metab. 2006;91(11):4459-4466.PubMedGoogle ScholarCrossref
Kelley  DE, Thaete  FL, Troost  F, Huwe  T, Goodpaster  BH.  Subdivisions of subcutaneous abdominal adipose tissue and insulin resistance.  Am J Physiol Endocrinol Metab. 2000;278(5):E941-E948.PubMedGoogle Scholar
Campbell  KL, Foster-Schubert  KE, Makar  KW,  et al.  Gene expression changes in adipose tissue with diet- and/or exercise-induced weight loss.  Cancer Prev Res (Phila). 2013;6(3):217-231.PubMedGoogle ScholarCrossref
King  NA, Hopkins  M, Caudwell  P, Stubbs  RJ, Blundell  JE.  Individual variability following 12 weeks of supervised exercise: identification and characterization of compensation for exercise-induced weight loss.  Int J Obes (Lond). 2008;32(1):177-184.PubMedGoogle ScholarCrossref
Swift  DL, Johannsen  NM, Lavie  CJ, Earnest  CP, Church  TS.  The role of exercise and physical activity in weight loss and maintenance.  Prog Cardiovasc Dis. 2014;56(4):441-447.PubMedGoogle ScholarCrossref
Church  TS, Earnest  CP, Thompson  AM,  et al.  Exercise without weight loss does not reduce C-reactive protein: the INFLAME study.  Med Sci Sports Exerc. 2010;42(4):708-716.PubMedGoogle ScholarCrossref
Myers  CA, Johnson  WD, Earnest  CP,  et al.  Examination of mechanisms (E-MECHANIC) of exercise-induced weight compensation: study protocol for a randomized controlled trial.  Trials. 2014;15(1):212.PubMedGoogle ScholarCrossref
Sims  ST, Kubo  J, Desai  M,  et al.  Changes in physical activity and body composition in postmenopausal women over time.  Med Sci Sports Exerc. 2013;45(8):1486-1492.PubMedGoogle ScholarCrossref
Kushi  LH, Doyle  C, McCullough  M,  et al; American Cancer Society 2010 Nutrition and Physical Activity Guidelines Advisory Committee.  American Cancer Society Guidelines on nutrition and physical activity for cancer prevention: reducing the risk of cancer with healthy food choices and physical activity.  CA Cancer J Clin. 2012;62(1):30-67.PubMedGoogle ScholarCrossref
Physical Activity Guidelines Advisory Committee. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC: US Department of Health and Human Services; 2008. http://www.health.gov/PAguidelines/Report/pdf/CommitteeReport.pdf. Accessed May 24, 2015.
Campbell  KL, Foster-Schubert  KE, Alfano  CM,  et al.  Reduced-calorie dietary weight loss, exercise, and sex hormones in postmenopausal women: randomized controlled trial.  J Clin Oncol. 2012;30(19):2314-2326.PubMedGoogle ScholarCrossref
Fabian  CJ, Kimler  BF, Donnelly  JE,  et al.  Favorable modulation of benign breast tissue and serum risk biomarkers is associated with > 10 % weight loss in postmenopausal women.  Breast Cancer Res Treat. 2013;142(1):119-132.PubMedGoogle ScholarCrossref
Original Investigation
September 2015

Effects of a High vs Moderate Volume of Aerobic Exercise on Adiposity Outcomes in Postmenopausal Women: A Randomized Clinical Trial

Author Affiliations
  • 1Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada
  • 2Department of Oncology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
  • 3Cross Cancer Institute, CancerControl Alberta, Alberta Health Services, Edmonton, Alberta, Canada
  • 4School of Public Health, University of Alberta, Edmonton, Alberta, Canada
  • 5Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada
JAMA Oncol. 2015;1(6):766-776. doi:10.1001/jamaoncol.2015.2239

Importance  Body fat increases postmenopausal breast cancer risk. Physical activity may decrease risk through adiposity changes, but the optimal dose of activity is unknown.

Objective  To compare the effects of 300 vs 150 min/wk of moderate to vigorous aerobic exercise on body fat in postmenopausal women.

Design, Setting, and Participants  The Breast Cancer and Exercise Trial in Alberta was a 12-month, 2-armed, 2-center randomized dose-comparison trial conducted from June 2010 through June 2013. Participants were 400 inactive postmenopausal women with body mass index 22 to 40, disease-free, nonsmokers, and nonusers of exogenous hormones.

Interventions  Five d/wk of aerobic exercise (3 d/wk supervised, 2 d/wk unsupervised) for 30 min/session (moderate-volume) or 60 min/session (high volume) achieving 65% to 75% of heart rate reserve for at least 50% of each session. Participants were asked not to change usual diet.

Main Outcomes and Measures  Total body fat, measured from dual energy x-ray absorptiometry scans, was the primary outcome. Other measures included subcutaneous and intra-abdominal fat from computed tomography scans, weight, and waist and hip circumferences.

Results  Of 400 women, 384 provided baseline and follow-up adiposity measurements. Median (interquartile range) adherence at full prescription for the high- and moderate-volume groups was 254 (166-290) and 137 (111-150) min/wk, respectively. Mean reductions in total fat were significantly larger in the high- vs moderate-volume group (least-squares mean difference, −1.0% [95% CI, −1.6% to −0.4%], P = .002). Subcutaneous abdominal fat and waist to hip ratio decreased significantly more in the high-volume group (least-squares mean difference, −10.8 [95% CI, −19.5 to −2.2] cm2, P = .01, and −0.01 [95% CI, −0.02 to 0.00], P = .04, respectively). Changes in weight and intra-abdominal fat were not significantly different between groups (least-squares mean difference, −0.7 [95% CI, −1.6 to 0.2] kg, P = .11, and −1.5 [95% CI, −5.9 to 2.9] cm2, P = .50, respectively). Some dose-response effects were stronger for obese women.

Conclusions and Relevance  In previously inactive postmenopausal women, a 1-year prescription of moderate to vigorous exercise for 300 min/wk was superior to 150 min/wk for reducing total fat and other adiposity measures, especially in obese women. These results suggest additional benefit of higher-volume aerobic exercise for adiposity outcomes and possibly a lower risk of postmenopausal breast cancer.

Trial Registration  clinicaltrials.gov: NCT01435005