Testosterone Replacement and Resistance Exercise in HIV-Infected Men With Weight Loss and Low Testosterone Levels.

Bashin S, Storer TW, Javanbakht M, et al (Division of Endocrinology, Metabolism, and Molecular Medicine, Charles R Drew University of Medicine and Science, Los Angeles, Calif), JAMA. 2000;283:763-770.

According to the authors, weight loss associated with human immunodeficiency virus (HIV) has been shown to have adverse effects on the disease outcome. Serum testosterone levels are lower in men with HIV who have weight loss, and these levels correlate with muscle mass deficits and disease progression. Replacement doses of testosterone can increase lean body mass and muscle strength in men with decreased endogenous testosterone production. Exercise and testosterone are relatively inexpensive and safe treatment methods. Based on this information, the authors hypothesized that testosterone replacement may also increase muscle mass and strength in men with HIV who have low testosterone levels.

The objective of the study was to determine the effects of testosterone replacement, with or without exercise, on muscle strength and body composition in men with HIV who have accompanying weight loss and low testosterone levels. The authors hypothesized that testosterone and resistance exercise would each increase muscle strength and fat-free mass and that the 2 interventions combined would produce greater gains than each intervention alone.

The authors conducted a double-blind, placebo-controlled, randomized study over the course of 16 weeks. The participants were 61 men with HIV who were between the ages of 18 and 50 years; they all had associated weight loss and low serum testosterone levels. Forty-nine of the 61 participants completed the study.

The participants were randomly assigned to 1 of 4 groups. The 4 groups did not significantly differ in age, height, weight, prior weight loss, or baseline testosterone levels. Group 1 received placebo injections and did not exercise; group 2 received 100 mg of testosterone enathate per week and did not exercise; group 3 received placebo injections and participated in a resistance exercise program; and group 4 received testosterone and exercised. The exercise intensity was standardized based on a one-repetition maximum. The exercise program consisted of 5 exercises (leg presses, leg curls, bench presses, latissimus pulls, and overhead presses) and progressed from low-intensity, high-volume exercise to higher intensity and lower volume over the course of 16 weeks. The participants were given dietary instructions 2 weeks before treatment initiation, and these instructions were reinforced every 2 weeks thereafter.

The main outcome measures were changes in muscle strength, body weight, thigh muscle volume, and lean body mass. Muscle strength significantly increased in the exercise-alone, testosterone-alone, and testosterone-and-exercise groups; however, the testosterone-and-exercise group did not show significantly higher gains than the groups that received a single intervention. Muscle strength did not change in the placebo-alone group. Body weight significantly increased in the exercise-alone and testosterone-alone groups, but it did not change in the placebo-alone group and did not change significantly in the exercise-and-testosterone group. The thigh muscle volume did not significantly change in the placebo-alone group, but increased in all the other groups. Lean body mass increased significantly in the testosterone-alone and exercise-alone groups, but it did not change significantly in the placebo-alone group. The effects of both interventions together were not significantly greater than each intervention alone.

According to the authors, testosterone replacement therapy and resistance exercise program each was associated with gains in muscle strength, body weight, thigh muscle volume, and lean body mass in men with HIV who had moderate weight loss and low testosterone levels. However, the effects of combining testosterone and exercise were not additive and did not produce greater gains than each intervention alone.

Daniel Rovny, PT, CSCS S. C. O. T. T. Physical Therapy Brooklyn, NY