That means your metabolism slows down, your brain makes you think you are constantly hungry and your body refuses to burn fat. When you have leptin resistance guess what happens? Leptin is a hormone secreted by fat cells and it’s supposed to control your appetite, and metabolism and tell your brain to burn fat. While levels below 300 ng/dL are considered clinically low total testosterone, McDevitt says that symptoms can appear even in a healthy range. Even if your total testosterone levels are in a normal range, your free testosterone can still be low. Free testosterone should make up about 1 to 2 percent of your total testosterone levels. Most men focus on total testosterone levels when they’re trying to figure out if they have low testosterone, but free testosterone levels matter, too. You’d not be sleeping well, you’d have no sex drive, you’d be fatigued, you’d have no muscle mass, you’d have uncontrolled glucose levels and more." Nutrients like zinc, magnesium, vitamin D, and healthy fats (e.g., omega-3 fatty acids) are important for maintaining healthy testosterone levels. However, long-duration endurance running might lead to a decrease in testosterone due to the body's stress response. In conclusion, testosterone is a vital hormone for runners, influencing their speed, stamina, and overall performance. Regular blood tests can help track hormone levels and ensure they remain within a healthy range. As runners get older, their natural testosterone levels tend to decline. Lifestyle changes such as regular exercise, a balanced diet, and adequate sleep can help increase testosterone production. Some studies suggest that these supplements can enhance muscle mass and improve endurance. In the same group, the I-postT T-Testo were also increased and remained elevated at 30 min into the recovery. Zmuda et al. examined the acute effect of moderate physical activity with increasing intensity on T-Testo in elderly (70 ± 4 years), sedentary men. Studies in older participants refer to studies in men with an average age of 60 ± 5 years. This is secondary to the decreasing capacity of aging Leydig cells to produce testosterone in response to LH stimulation . 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. When cortisol levels remain elevated for extended periods—due to work pressure, lack of rest, or mental burnout—production tends to drop. Stress activates the release of cortisol, a hormone that has an inverse relationship with testosterone. A study published in Sleep Science found that t-levels dropped by 10–15% after just five nights of only five hours of sleep. During deep sleep, your body produces the majority of its daily testosterone. Table 2 shows ergospirometric and body composition variables in the runners during the season. Always at nine o’clock in the morning, to limit the impact of circadian rhythms on hormonal concentrations, after weighing the participants, ten milliliters of antecubital venous blood was drawn from each participant. In addition, they performed two weekly sessions of resistance training during the whole athletics season. The data were obtained at the aerobic threshold (VT1) and the anaerobic threshold (VT2) to determine training load intensity. Aerobic endurance athletes have lower baseline values and higher insulin sensitivity than sedentary subjects to support fatty acid oxidation . Horton, Grunwald, Lavely and Donahoo reported a decrease in plasma I concentration during exercise, followed by an increase during the hours after exercise to favor glycogen repletion, a decrease in carbohydrate oxidation, and an increase in fat oxidation . Another study investigated the effect of a combination of exercise intensity, muscle volume (i.e., number of sets and repetition per a set), and the duration of the resting period between the sets on the acute hormonal variations . Not much has been reported about the effect of variable vs. constant exercise intensities on serum testosterone concentrations. Resistance exercise, also known as strength and weight training, involves the voluntary activation of specific skeletal muscles against some form of external resistance. For example, in the above-mentioned study by Kraemer et al. the increase in T-Testo was at 25 min after the start of the exercise, and thus it is possible that not only the intensity but also the duration of the exercise contributed to these results.
