Overtraining can have several negative effects on your condition, such as your getting weaker and slower. Being in an overtrained state can also increase your risk of injury. This is not something that develops after a single training session or even a short training cycle; overtraining takes time to develop. Recovering from overtraining also takes time. Consult your physician before beginning any diet or exercise program.
Overtraining is an imbalance between your training and your body’s ability to recover. This is not just a matter of being tired from a few workouts, but a state in which your body’s endocrine system is stressed beyond its ability to promote recovery from training. Signs of overtraining include weakness, lack of appetite, insomnia and depression. There is no method of precisely determining when an overtrained state has been achieved. Recovery can take from weeks to months.
Overtraining can reduce strength secondary to depression of the neuroendocrine system. Different responses to overtraining from resistance exercises may occur depending on why you are overtrained. Regardless of gender, if your testosterone levels become depressed, you will not recover from training stress as effectively. This both limits your progress and increases your risk of further overtraining should you attempt to progress. Your cortisol levels will rise, and cortisol is a hormone that promotes muscle wasting and fat storage.
Overtraining from endurance exercise can not only result in a loss of endurance, but coordination as well. This significantly increases your risk of injury secondary to fatigue and poor technique. Overtraining may also present as a decrease in your ability to process oxygen or maintain a steady heart rate. Because endurance training is an attempt to improve your cardiovascular fitness, overtraining in this area works at cross purposes to your goal. Long-term overtraining can also result in depression or altered mood states.
To recover from overtraining, you need to cut your training volume and intensity. You also need to ensure that you are getting enough fatty acids. Your ability to produce steroidal hormones such as testosterone is limited if you are following a low-fat diet. You can spend time on skill development, but when attempting to recover from overtraining, do not attempt complex drills because your coordination may be affected. Attempting to learn skills while uncoordinated due to overtraining builds sloppy movement patterns.
Source – Livestrong.com