The cardiovascular effects of testosterone (T) are controversial. Low T has been associated with accelerated vascular aging, characterized by large elastic artery stiffening (decreased compliance), intimal-medial thickening (IMT), and endothelial dysfunction. Endurance exercise improves vascular function, but resistance training may increase arterial stiffness. We sought to determine whether T supplementation improved markers of vascular aging in men with low-normal T and whether T supplementation prevented arterial stiffness with resistance exercise. We studied 160 community-dwelling older men (66 ± 5 yr) with low-normal baseline total T levels (200-350 ng/dl). Participants were randomized to transdermal T gel targeting either a lower (400-550 ng/dl) or higher (600-1,000 ng/dl) T range or to placebo gel and to either progressive resistance training (PRT) or to no exercise for 12 mo. Carotid artery stiffness (arterial compliance) and carotid IMT were measured at baseline, 6 mo, and 12 mo. Endothelial function (brachial artery flow-mediated dilation) was measured in a subset (n = 86). Changes in carotid artery compliance, IMT, and endothelial function with either the lower or higher range of T supplementation were not different from placebo at 6 or 12 mo. There were no differences between PRT and no PRT groups, alone or with T supplementation, in changes in any of the vascular measures at either time point. Supplementation of T and PRT in older men with low-normal levels do not appear to improve or harm vascular function.NEW & NOTEWORTHY Increased promotion and prescription of testosterone (T) to aging men has raised concerns about potential adverse cardiovascular effects. We show that in older men with T levels in the low-normal range, 12 mo of T supplementation with or without resistance exercise did not improve or harm vascular function.
Keywords: arterial stiffness; endothelial function; resistance exercise; testosterone; vascular function.