Many of us experience acute fatigue during the training process that requires rest and recovery to continue making progress. Overtraining is more than this and much more serious and usually takes weeks or months to fix.
Overtraining is a state of chronic fatigue and underperformance caused by a prolonged imbalance between training stress and recovery. It occurs when an athlete engages in excessive training volume, intensity, or frequency without allowing enough time for proper rest, nutrition, and adaptation.
Overtraining is associated with a number of physiological and psychological changes. These may include a decrease in maximal oxygen uptake, impaired cardiovascular function, decreased muscle strength and power, altered hormone levels, and increased oxidative stress and inflammation.
The mechanisms behind overtraining are complex and multifactorial. They involve disruptions in the delicate balance between anabolic and catabolic processes, as well as disturbances in the autonomic nervous system and the immune system.