There are relatively few studies that have proven the link between exercise and the reduction of anxiety and depression. However, anyone who has returned from the gym, a long bike ride, or a successful competition realizes the powerful affect exercise can have on one's mental health.
As we say in psychology,"Normal is a setting on a washing machine.". Being normal just doesn't exist. Some problems are more debilitating than others but for most of us we are able to get out of bed and face life. Some days better than others.
I have always wondered what role exercise plays in not just our physical health but also in our mental health. It is quite apparent to me that endurance training provides relief for those suffering from most anxiety disorders and possibly even depression. The danger of using exercise as an intervention for common mental inhibitors is the same as using medication. The right amount is critical. Too much and you get all kinds of negative things happening. Not enough, and you don't get the maximum benefit of the exercise. In addition, you need the right amount but also at the right time to prevent boredom and excessive mental fatigue.
There seems to be many parallels with exercise and medication for both physical problems as well as mental problems. Many, if not all, physical ailments can be either eliminated or lessened by a reasonable amount of exercise coupled with a healthy diet. What is the most common thing your doctor says when you enter their office? Do you exercise? Do you eat right? However, rarely does a psychologist and/or psychiatrist prescribe exercise in oder to reduce anxiety or lesson depression. Why not? In my opinion exercise has as much positive benefit to one's mental health as it does to one's physical health.
Another related aspect psychology has with medicine is the prescription of medication. The quick fix. Just take this pill and you don't have to do anything. You will feel better. Lose weight. You will be happy both mentally and physically just by taking a couple pills everyday. Again, it is well established that taking pills to improve one's general health (blood pressure, cholesterol, obesity)works. However, it also well established that changes in diet and exercise can provide almost the exact physical health benefits. But again, very rarely is exercise and diet prescribed to one suffering from generalized anxiety disorders, depression not otherwise specified, and a host of other DSM-IV disorders that are commonly treated with medication.
On the other hand, exercise, just like medication, can be abused. Too much is not good either, nor is it very healthy. For many, exercise can be used as a socially acceptable method of avoiding life's responsibilities and facing life's inevitable challenges. For many, training for long distance triathlons, ultra-distance marathons, and the like are not as much about challenging themselves physically as they are about avoiding some mental aspect in their life and/or dealing with possible post traumatic stress that has never been resolved. A may also be a form of narcisism. Either way, these events are definitely less about physical fitness than they are about some other factor in one's life that is being compensated for. Is this bad? I really don't know the answer to that. I believe it isn't so bad if the only one being affected is the person in these types of events. However, a father who is never around for his son or wife and/or a wife who avoids her husband or daughter in order to train is definitely not healthy from a psychological perspective. Is it possible to do both? I imagine so...especially when considering shorter endurance events and the reduced commitments necessary to train and be competitive.