Potential Adverse Biological Effects of Excessive Exercise and Overtraining Among Healthy Individuals

Abstract

Background. A growing body of research has investigated the potential health risks of excessive exercise on human health. There is now a clear need for an up-to-date, critical synthesis of reliable findings on this topic.

Objective. To determine the potential adverse biological effects of excessive exercise and overtraining among - initially - healthy men and women. Design. Brief review. Material and method. In order to identify relevant studies, the electronic database Medline was searched using the following terms/key words: "excessive exercise" OR "overtraining"" AND "adverse effects". Studies had to: a) be written in English, b) published from January 1980- March 2014, and c) involve healthy men and women (individuals with no pre-existing medical conditions). Results and discussion. The main adverse effects associated with excessive exercise and overtraining among healthy individuals were musculoskeletal injuries, adverse cardiovascular effects, exercise-induced muscle damage, exercise-related alterations of immunity, exercise-related reproductive dysfunction, chronic negative energy balance, osteoporosis, and sleep disorders. Conclusions. The findings of the present study suggest that excessive exercise and overtraining can have serious health consequences. Sports physicians, trainers and health educators should be aware of these risks and advise the people accordingly. Further research needs to be carried out in this area, including high quality trials.