This book discusses major changes in our understanding of the most prevalent non-orthopedic, sports-related condition   overtraining syndrome (OTS), arguing that it should be considered as the manifestation of burnout in athletes, rather than simply the result of excessive training.  While the chronic adaptations of the cardiovascular and musculoskeletal systems to exercise are well documented, those of the endocrine system are less well known, and adaptations of the hormonal ranges for athletes are yet to be determined. There is also a lack of standardized diagnostic criteria, consistent assessment methods and biomarkers.  This book offers a systematic review of the hormonal aspects of overtraining syndrome, and a comparison with sports-related syndromes triggered by chronic deprivation of different sorts, including the female athlete triad (and its derivative, RED-S) and burnout syndrome of the athlete (BSA).