A study was recently published with the rather ungainly title, “Longitudinal Gains in Self-Regulation from Regular Exercise”. – http://www.ncbi.nlm.nih.gov/pubmed/17032494 – Some of these studies have titles that are almost impossible to understand, however, stick with me for a moment, because the conclusions drawn from it were quite cool. 
The authors did the following; they got a group of people together and measured a number of psychological markers. These included how much stress they felt that they were going through, their emotional state, and their ability to deal with life stresses. They measured these factors for a period of four months, so as to achieve a stable understanding of their subjects. After this time, they put their subjects through a period of 4 months during which regular physical exercise was taken. The chief finding from this period was that people experienced an increase in self-regulatory capacity. 
To break this down a bit, a lack of self regulatory capacity means that you are more prone to impulse and acting on short term desires. An increase in a person’s ability to self regulate, implies that he/she is more disciplined, and is able to make decisions that are in line with preset goals and values.
So, people put on an exercise program displayed the following increases and decreases in behavior.
Decreases in the following:
Perceived stress
Emotional distress
Smoking
Alcohol consumption
Caffeine consumption
Increases in the following: 
Healthy eating
Emotional control
Maintenance of household chores
Attendance to commitments
Monitoring of spending
Improvement in study habits
The trick with these two lists is as follows, have a look at both the ‘decrease’ and ‘increase’ lists. Put a tick next to each behavior that you want to attend to, and then, go for a run.
I realize that the above point may be a bit simplistic but there is a lot of truth in it.
Regards,
Mike Roscoe.
