Over-training or over-exercising can be counterproductive to achieving your fitness goals. Over-training usually occurs when you do not allow your body to adapt, adjust, and recuperate in response to an exercise training regimen. Signs that you are over-training include decreased performance, increased resting heart rate and blood pressure, increased muscle fatigue, poor sleep, gastro-intestinal disturbances, depression, irritability, apathy, and even low self-esteem. Dr. Adrian Shepard from Butler University suggests the following to avoid over-training: gradually work your way into exercise, ask the staff at your fitness center about how to correctly use the equipment, and ask for a fitness assessment to determine current physical health status and fitness level so appropriate exercises can be recommended and goals can be set.
Butler University, January 2010