First, the study was exploratory in nature and involved a relatively small sample size, which may have reduced the statistical power. They also reported that the exercise reduced urinary tract symptoms and improved the quality of life. For each disease, there were 17 patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (19.5%), 8 patients with hypertension (9.2%), 8 patients with hyperlipidemia (9.2%), 7 patients with diabetes mellitus (8.0%), and 4 patients with other diseases (4.6%) (Table 1). There were 55 patients with no underlying diseases (63.2%), while 10 patients had more than 1 underlying diseases (11.5%). Further, some patients with normal testosterone levels and only relatively healthy patients with ED who were able to undergo the basic exercise testing were included in the present study. In this study, the threshold of serum testosterone level used for analysis was also confirmed with respect to body composition and physical fitness factors that showed a significant correlation with serum testosterone levels. Nevertheless, these studies demonstrate that there is a possibility of increasing serum testosterone levels through aerobic exercise. Thus, aerobic exercise, which reduces fat mass and improves cardiorespiratory fitness, is expected to be more beneficial than strengthening exercise in increasing serum testosterone levels. Furthermore, the increased serum testosterone levels were relatively well maintained in the group that continued to perform the exercises after cessation of the testosterone treatment. The correlations between serum testosterone levels and the results from the body composition and basic exercise tests were investigated. Kumagai et al. investigated the effect of a 12-week aerobic exercise intervention on circulating serum testosterone concentrations in overweight/obese men. Thus, although low basal testosterone concentration is likely due to HPA suppression and hypogonadotropic hypogonadism during chronic exercise, additional contributing factors affecting the serum testosterone concentrations in the absence of LH suppression are yet to be determined. The effect of exercise on serum testosterone concentrations in older men is not clearly understood. Studies investigating the effect of exercise on serum testosterone concentrations in overweight and obese individuals also show conflicting results. So far, we have discussed works done in lean, young men; however, body weight and aging are inversely related to serum testosterone concentrations . Others have demonstrated that an increase in serum testosterone concentrations is not secondary to increased production rate 55,56. Several studies have sought to investigate the potential underlying mechanisms that may explain these outcomes. Lastly, Tremblay et al. evaluated the effect of baseline physical activity status on hormonal changes after an exercise protocol. The first two steps were at intermittent intensity of 60% and 75% VO2max for 10 min each (i.e., step 1 and step 2, respectively). Regarding the study populations, the majority of research done using running as a study approach was conducted in elite athletes. Although different types of endurance exercises have been performed, running and ergometer cycling with different protocols were most often used. As many conditions can alter the plasma concentration of sex hormone binding globulins, interpretation of T-Testo and F-Testo should take these conditions into consideration. The effect of exercise on basal serum testosterone concentrations in obese individuals has been evaluated in multiple studies. Nicklas et al. reported no significant change in basal serum testosterone concentrations after 16 weeks of progressive resistance training program. Interestingly, some studies have even shown that chronic endurance exercise can correlate inversely with basal serum testosterone concentrations. Many studies have addressed the effect of habitual or intervention exercise on basal (resting) serum testosterone concentrations, with no clear effect reported so far. In this study, no changes were observed in the resting concentrations of serum testosterone in middle-aged men, but resting testosterone concentrations increased in young men post-training. Both groups showed significant increases in serum testosterone concentrations immediately and 5, 10, and 15 min post-exercise. Sheikholeslami-Vatani et al. investigated the acute effect of different resistance exercise orders on serum testosterone concentrations in untrained normal weight and obese men. Focus on stretching major muscle groups to improve flexibility, reduce muscle tension, and promote relaxation. Chronic stress elevates cortisol, which can suppress testosterone production. Yes, stretching promotes relaxation and reduces muscle tension, which can improve sleep quality.
