title: Dose-Response Effects of Aerobic Exercise on Quality of Life in Postmenopausal Women: Results from the Breast Cancer and Exercise Trial in Alberta (BETA).
abstract: BACKGROUND
  Exercise generally improves quality of life (QoL) and psychosocial functioning in adult populations but few randomized trials have examined dose-response effects.
  
  
  OBJECTIVE
  The purpose of the present study was to report the QoL and psychosocial outcomes from the Breast Cancer and Exercise Trial in Alberta (BETA).
  
  
  METHODS
  Healthy but inactive postmenopausal women at risk for breast cancer were randomized to a year-long aerobic exercise intervention consisting of either 150 min/week (moderate volume group, n = 200) or 300 min/week (high volume group, n = 200). QoL was assessed at baseline and 1 year using the short form-36 health survey. Sleep quality, depression, anxiety, stress, self-esteem, and happiness were also assessed. Participant preference for group assignment (i.e., exercise volume) was assessed at baseline and tested as a moderator.
  
  
  RESULTS
  There were no statistically significant dose-response effects of aerobic exercise on any QoL, sleep quality, or psychosocial outcome. Participant preference for group assignment did not moderate any QoL, sleep quality, or psychosocial responses. Marital status was a significant moderator (p for interaction = 0.01) and obesity showed a trend towards being a moderator (p for interaction = 0.08) of the dose-response effects of aerobic exercise on global sleep quality such that unmarried and obese women improved sleep quality with the higher volume of aerobic exercise.
  
  
  CONCLUSIONS
  A higher volume of aerobic exercise, approximately double the minimum public health guideline, did not provide additional QoL or psychosocial benefits compared to the minimum public health guideline in inactive postmenopausal women, even for women who preferred the higher volume of exercise at baseline.
  
  
  BACKGROUND
  Trial Registration clinicaltrials.gov identifier: NCT1435005.
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, 1-113 University Hall, Edmonton, Alberta, T6G 2H9, Canada. kerry.courneya@ualberta.ca.
authors.forename: Kerry S
authors.initials: KS
authors.lastname: Courneya
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada.
authors.forename: Jessica
authors.initials: J
authors.lastname: McNeil
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada.
authors.forename: Rachel
authors.initials: R
authors.lastname: O'Reilly
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, 1-113 University Hall, Edmonton, Alberta, T6G 2H9, Canada.
authors.forename: Andria R
authors.initials: AR
authors.lastname: Morielli
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada.|Departments of Oncology and Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Friedenreich
mesh_terms: D000368:Aged; D000416:Alberta; D001007:Anxiety / Q000523:psychology; D001943:Breast Neoplasms / Q000523:psychology; D003863:Depression / Q000523:psychology; D015444:Exercise / Q000523:psychology*; D005260:Female; D006240:Happiness; D006306:Health Surveys; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000523:psychology*; D011788:Quality of Life / Q000523:psychology*; D012649:Self Concept; D012890:Sleep / Q000502:physiology; D013315:Stress, Psychological / Q000523:psychology; D016896:Treatment Outcome; D016387:Women's Health
keywords: Anxiety; Depression; Happiness; Physical activity; Sleep quality; Stress