title: Effect of exercise on serum sex hormones in men: a 12-month randomized clinical trial.
abstract: OBJECTIVE
  The effect of exercise on androgens in middle-aged to older men is poorly understood, and it could have implications for several aspects of health. This analysis was conducted to examine the effects of long-term aerobic exercise on serum sex hormones in middle-aged to older men.
  
  
  METHODS
  One hundred two sedentary men, ages 40-75 yr, were randomly assigned to a 12-month exercise intervention or a control group (no change in activity). The combined facility- and home-based exercise program consisted of moderate/vigorous-intensity aerobic activity for 60 min.d(-1), 6 d.wk(-1). Serum concentrations of testosterone, free testosterone, dihydrotestosterone (DHT), 3alpha-androstanediol glucuronide (3alpha-Diol-G), estradiol, free estradiol, and sex hormone-binding globulin (SHBG) were measured at baseline, 3, and 12 months.
  
  
  RESULTS
  Exercisers trained a mean of 370 min.wk(-1) (102% of goal), with only two dropouts. Cardiopulmonary fitness (.VO(2max)) increased 10.8% in exercisers and decreased by 1.8% in controls (P < 0.001). DHT increased 14.5% in exercisers versus 1.7% in controls at 3 months (P = 0.04); at 12 months, it remained 8.6% above baseline in exercisers versus a 3.1% decrease in controls (P = 0.03). SHBG increased 14.3% in exercisers versus 5.7% in controls at 3 months (P = 0.04); at 12 months, it remained 8.9% above baseline in exercisers versus 4.0% in controls (P = 0.13). There were significant trends toward increasing DHT and SHBG, with greater increases in .VO(2max) at 3 and 12 months in exercisers. No statistically significant differences were observed for testosterone, free testosterone, 3alpha-Diol-G, estradiol, or free estradiol in exercisers versus controls.
  
  
  CONCLUSIONS
  A year-long, moderate-intensity aerobic exercise program increased DHT and SHBG, but it had no effect on other androgens in middle-aged to older men.
authors.affiliation: Cancer Prevention Program, The Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
authors.forename: Vivian N
authors.initials: VN
authors.lastname: Hawkins
authors.forename: Karen
authors.initials: K
authors.lastname: Foster-Schubert
authors.forename: Jessica
authors.initials: J
authors.lastname: Chubak
authors.forename: Bess
authors.initials: B
authors.lastname: Sorensen
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Ulrich
authors.forename: Frank Z
authors.initials: FZ
authors.lastname: Stancyzk
authors.forename: Stephen
authors.initials: S
authors.lastname: Plymate
authors.forename: Janet
authors.initials: J
authors.lastname: Stanford
authors.forename: Emily
authors.initials: E
authors.lastname: White
authors.forename: John D
authors.initials: JD
authors.lastname: Potter
authors.forename: Anne
authors.initials: A
authors.lastname: McTiernan
mesh_terms: D050154:Adiposity / Q000502:physiology; D000328:Adult; D000368:Aged; D000728:Androgens / Q000032:analysis* / Q000097:blood; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D014861:Washington
chemical_list: D000728:Androgens