Relative Energy Deficiency in an Elite Professional non-Endurance Male Caused by Short Period of Overtraining and Caloric Restriction: A Case Report

Abstract Background: Relative energy deficiency in sports (RED-S) is well-recognized in women competing in endurance sports; however, it is less common in males competing in non-endurance sports. Here, we report a case of hypogonadotropic hypogonadism associated with RED-S in an elite male non-endurance skill athlete caused by a change in workout over a short time frame.Case presentation: An 18-year-old elite male non-endurance skill athlete complained of fatigue, depression, and inattention. Blood tests showed low total testosterone levels and a physical examination revealed Tanner stage phase IV-V. A gonadotropin-releasing hormone (GnRH) stimulation test revealed that the luteinizing hormone (LH) level was 10 times above normal, suggesting hypothalamic hypogonadism. However, magnetic resonance imagings (MRI) of pituitary gland, brain, and adrenal glands were normal. Due to COVID-19 pandemic, he was quarantined for 2 weeks. During that time, he only performed a basic workout. At the end of quarantine, his coach made him follow a new training program that was >50% more intense than the one before quarantine. He also had to restrict calorie intake for snowboarding. He was diagnosed as relative energy deficiency in sport (RED-S). The condition resolved after lifestyle and training modifications.Conclusions: RED-S is not restricted to endurance athletes. Elite athletes performing non-endurance sports can also suffer from it after a significant modification of training. Sports scientists/trainers should monitor caloric intake and training intensity to avoid RED-S, protect the health and improve the performance of all athletes.