<p> The purpose of this study was to investigate the effects of acute sunlight exposure on post-resistance exercise testosterone levels. Testosterone and vitamin-D concentrations were measured pre- and post-resistance exercise in 5-minute increments during a 30-minute recovery and compared between two exercise trials: (1) regular recovery and (2) exposed to an ultraviolet light source (Sperti Vitamin D Light Box) for the first 10 minutes of recovery. </p><p> The results suggest that acute exposure to the ultraviolet light source did not provide sufficient stimulus to affect vitamin-D levels but significantly increased the testosterone response. These findings suggest that ultraviolet light is capable of positively influencing testosterone levels following a bout of resistance exercise.</p><p>