This review thoroughly explores all the available evidence concerning seasonal variations in testosterone levels. The impacts of melatonin, vitamin D, sleep-wake cycles, light exposure, physical activity, BMI, and waist circumference are also discussed.
—Baylor University College of Medicine
When you review the comments above by researchers at Baylor University’s College of Medicine, they imply that there is a verifiable link to declining levels of the anabolic hormone testosterone when the seasons change. Their remarks, however, appear to highlight that this irregularity has something to do with reduced exposure to sunlight. Those annotations also suggest that this reduced exposure to sunlight has a negative impact on various other hormones like melatonin that regulate normal sleep cycles. This mishap has been widely publicized due to the epidemic rise of body mass index (BMI) numbers and obesity here in the United States. Inadequate levels of sleep have been linked as a major causative factor in this epidemic, which disrupts normal fat-burning and hormonal-based metabolic mechanisms. Additionally, the remarks above also hint that reduced exposure to sunlight results in a marked decline in the production of the natural steroidal nutrient vitamin D, paralleled by slower rates of growth, despite consistent workouts. To this point, Richard Hobday, PhD, a leading authority on the history of sun therapy and t