Another NYTimes article supports the emotional benefits of exercise–at least in rats http://well.blogs.nytimes.com/2011/07/06/why-exercise-makes-us-feel-good/?pagemode=prin Draw your own conclusions but it adds to the research as well as personal anecdotes confirming that exercise reduces anxiety and possibly depression.
When aggressive alpha rats were confined with punier ones, the alphas so terrorized the other guys that they exhibited "anxiety-like" behavior even when away from the alphas.
After allowed to exercise at their own pace and degree they were much less anxious when away from the aggressors. They actually seemed "stress-resistant". And since these rats were not training for triathlons we can assume their exercise regimens were in the moderate range for rats.
Can we draw conclusions for human beings? And does it make any difference to the reader anyway?
The interplay of the mind and body manifest in physical symptoms. When we have stress related thoughts, we actually "feel" those thoughts in terms of an "anxious" feeling.
It begins with a thought, then instantaneously an emotion, then instantaneously physical manifestations. The cascading effect of stressful thoughts is so profound and so immediate that we tend to lump them all together. Yet it is fascinating to break the stress reaction into three steps: 1) thought, 2) emotion, 3) physical reactions/sensations. Ultimately we feel our thoughts and emotions in our body's reactions.
We breathe more rapidly, our speech quickens, our heart rate and blood pressure increase, our palms and arm pits may sweat, our eyes may dart around more quickly. We may feel palpitations, our necks and backs may tighten, our gastrointestinal tract may develop cramping, signaling the need to defecate.
Where does exercise fit into this scenario?
In my experience, it modifies, attenuates the physical manifestations. It breaks the third leg of the stress reaction. In may own case the best type of exercise is aerobic. When I run and sweat my body depletes itself of the catecholamines and adrenaline and whatever other peptides lead to the physical manifestations of stress. I "feel" relaxed because my body is relaxed. This, of course, does not change my thoughts or even my feelings. But when I don't "feel" the stress in my body, I'm OK.
Those of us who have incorporated "moderate" amounts of regular aerobic exercise into our lives seem to feel better, perhaps even more "stress-resisitant".
It seems to work for me.