Previous studies of testosterone supplementation in HIV-infected men failed to demonstrate
improvement in muscle strength. The effects of resistance exercise combined with testosterone
supplementation in HIV-infected men are unknown.
To determine the effects of testosterone replacement with and without resistance exercise
on muscle strength and body composition in HIV-infected men with low testosterone
levels and weight loss.
Placebo-controlled, double-blind, randomized clinical trial conducted from September
1995 to July 1998 at a general clinical research center.
Sixty-one HIV-infected men aged 18 to 50 years with serum testosterone levels of less
than 12.1 nmol/L (349 ng/dL) and weight loss of 5% or more in the previous 6 months,
49 of whom completed the study.
Participants were randomly assigned to 1 of 4 groups: placebo, no exercise (n = 14);
testosterone enanthate (100 mg/wk intramuscularly), no exercise (n = 17); placebo
and exercise (n = 15); or testosterone and exercise (n = 15). Treatment duration was
16 weeks.
Changes in muscle strength, body weight, thigh muscle volume, and lean body mass compared
among the 4 treatment groups.
Body weight increased significantly by 2.6 kg (P<.001) in men receiving testosterone
alone and by 2.2 kg (P = .02) in men who exercised alone but did not change in men
receiving placebo alone (-0.5 kg; P = .55) or testosterone and exercise (0.7 kg; P
= .08). Men treated with testosterone alone, exercise alone, or both experienced significant
increases in maximum voluntary muscle strength in leg press (range, 22%-30%), leg
curls (range, 18%-36%), bench press (range, 19%-33%), and latissimus pulls (range,
17%-33%). Gains in strength in all exercise categories were greater in men assigned
to the testosterone-exercise group or to the exercise-alone group than in those assigned
to the placebo-alone group. There was a greater increase in thigh muscle volume in
men receiving testosterone alone (mean change, 40 cm3; P<.001 vs zero change) or exercise
alone (62 cm3; P = .003) than in men receiving placebo alone (5 cm3; P = .70). Average
lean body mass increased by 2.3 kg (P = .004) and 2.6 kg (P<.001), respectively, in
men who received testosterone alone or testosterone and exercise but did not change
in men receiving placebo alone (0.9 kg; P = .21). Hemoglobin levels increased in men
receiving testosterone but not in those receiving placebo.
Our data suggest that testosterone and resistance exercise promote gains in body weight,
muscle mass, muscle strength, and lean body mass in HIV-infected men with weight loss
and low testosterone levels. Testosterone and exercise together did not produce greater
gains than either intervention alone.