Feeling lonely or shy? Go exercise.- daily

Steve over on Games Are For Children posted about his experiences with shyness and overcoming it, and an abstract from a paper:

The purpose of the current study was to estimate the relationship between exercise frequency and measures of shyness and loneliness in a sample of 882 college students. Analysis provided evidence that higher shyness and loneliness scores were associated with not exercising and infrequent exercising. Also, subjects who exercise 7 times a week scored significantly lower than the other exercise-frequency groups. Analysis of covariance, controlling for possible confounding variables, gives further support.

Now, this does not say anything if this is cause or effect. However, there are several effects from exercise that seems likely to contribute this way:

• Hormonal: Exercise burns cathecolamines (adrenaline and noradrenaline), which also lead to lower production of cortisol. Overall, this means lowered stress level.
• Hormonal: Exercise tends to regulate sleep, leading to more energy. (This may be the same effect as above, though I seem to remember an additional regulating effect on melatonin.)
• Physical/hormonal: Exercise regulates hunger appropriately, leading to more energy.
• Physical/Mental: Exercise leads to production of new brain cells, which seem to be involved in curing depression. Thus, more positive feelings/filters overall.
• Social/Physical: Exercise leads to looking better/healthier, which again gives more positive social feedback.
• Social: Many forms of exercise includes some social activity directly.

I used a google search for estimate the relationship between exercise frequency and measures of shyness and loneliness to find this; there seems to be more interesting articles popping up underneath.