Effects of testosterone and progressive resistance exercise in healthy, highly functioning older men with low-normal testosterone levels.

Context: Aging in men is associated with reduced testosterone (T) levels and physiological changes leading to frailty, but the benefits of T supplementation are inconclusive.

Objective: We studied the effects of T supplementation with and without progressive resistance training (PRT) on functional performance, strength, and body composition.

Design, Setting, And Participants: We recruited 167 generally healthy community-dwelling older men (66 ± 5 years) with low-normal baseline total T levels (200-350 ng/dL).

Intervention: Subjects were randomized to placebo or transdermal T gel [2 doses targeting either a lower (400-550 ng/dL) or higher (600-1000 ng/dL) T range] and to either PRT or no exercise for 12 months.

Main Outcome Measure: The primary outcome was functional performance, whereas secondary outcomes were strength and body composition.

Results: A total of 143 men completed the study. At 12 months, total T was 528 ± 287 ng/dL in subjects receiving any T and 287 ± 65 ng/dL in the placebo group. In the PRT group, function and strength were not different between T- and placebo-treated subjects, despite greater improvements in fat mass (P = .04) and fat-free mass (P = .01) with T. In the non-PRT group, T did not improve function but improved fat mass (P = .005), fat-free mass (P = .03), and upper body strength (P = .03) compared with placebo. There were fewer cardiovascular events in the T-treated groups compared with placebo.

Conclusions: T supplementation was well tolerated and improved body composition but had no effect on functional performance. T supplementation improved upper body strength only in nonexercisers compared with placebo.