The descriptive statistics provided an overview of the data distribution for each variable across the different phases of TRT. Descriptive statistics (mean ± standard deviation) were then calculated for all physical activity, exercise, and HR variables recorded by the wrist-worn device. Each exercise session aimed to include a minimum of 30 minutes of aerobic training and 30 minutes of strength training, ensuring a total exercise duration of at least 60 minutes per session. Based on the patient’s prior exercise history and experience, no formal or structured training program was provided during supplementation. The participant was instructed to perform their exercise sessions while the wrist-worn device continuously recorded their HR and to stop recording at the completion of each training session. Each HR zone corresponds to a different level of exercise intensity, with the ranges increasing as a percentage of HRmax. For the study, HR data was divided into five distinct zones based on the percentage of the participant's maximum heart rate (HRmax). The cumulative trends in HR intensity suggest adaptations to varying intensities as a response to TRT. The case report provides preliminary insights into physiological changes throughout six months of TRT supplementation in a middle-aged male. By the end of Phase 2 TRT, estradiol decreased but remained higher than baseline, indicating the persistent effects of TRT on estrogen levels. This approach ensured that changes over time were rigorously assessed, accounting for individual variability and repeated measures. The Food and Drug Administration (FDA) requires testosterone therapy drugs to carry a warning that they may increase the risk of heart attacks and strokes. Doctors sometimes prescribe testosterone gels, creams, or implants to people around the time they enter menopause. Testosterone supplements may also be useful for people with testosterone deficiency. During puberty in males, testosterone is responsible for the deepening of the voice, the growth of the male sexual organs, and the development of pubic hair. Natural testosterone supplements and boosters include vitamin D, fenugreek, or ashwagandha. Testosterone is the primary sex hormone in males but also has important functions in females. Testosterone replacement therapy (TRT) with cypionate has gained significant attention in recent years as a potential intervention for increasing muscle mass and reducing fat mass . These findings highlight the exercise approaches and HR responses potentially required for significant body recomposition and improved metabolic health with TRT. Daily step counts and strength and aerobic exercise data were tracked utilizing a wrist-worn device (Polar Ignite 2) and an HR chest strap (Polar H10) to monitor time accumulated in five different HR zones (HR Zone 1-5). Future trends include improved sensor technology, better integration with health apps, and personalized medicine approaches driven by continuous monitoring of hormone levels. It may also perhaps reflect a lowering of the set-point (i.e., readjustment) of the axis for what is deemed a necessary minimal amount of circulating testosterone for proper physiological function (i.e., endurance athletes have reduced amounts of muscle mass compared to many other athletes). The terminology to refer to these endurance-trained men with low resting testosterone had not been universally standardized, but in 2005 researchers from our laboratory group proposed the use of the phrase the "exercise-hypogonadal male" as a name to refer to this condition . One of the body’s physiological systems that is extremely sensitive to the stress of exercise training is the endocrine system. It is reasonable to suggest that TRT enhances the effect of exercise and promotes an increase in lean mass while simultaneously reducing body fat percentage, setting it apart from traditional weight loss methods like GLP-1 agonists. The body composition changes observed in this study, specifically the increase in lean body mass and the simultaneous decrease in body fat percentage, are consistent with findings from other TRT research 3,4. In summary, it appears that the body’s anabolic response can persist despite a shift toward lighter-intensity exercise zones and declining hormone levels, as long as these levels remain elevated compared to non-supplementation periods. Overall, the data indicates that TRT contributed to increased muscle mass, a higher metabolic rate, and a leaner body composition, despite overall weight gain. Body weight continued to increase, gaining an additional 3.8%, but this was largely attributed to a 6% increase in lean body mass and a 6.9% increase in skeletal muscle mass, while body fat percentage decreased by 1.7%. The body composition results demonstrate noticeable changes across different phases of the study, indicating positive shifts in muscle mass and metabolic rate throughout the TRT phases (Table 1). Throughout the TRT phases, total and free testosterone levels showed significant increases (Figure 1).
