Wednesday, December 16, 2009

Runner's High-Part 2

After perusing the dark corners of the internet in between doing my actual work, I’ve concluded that there is a wealth of information about how running supposedly aids in alleviating depression. A number of studies done over the last few years provide compelling support for the proposition that aerobic exercise, and running in particular, can be as effective as pharmaceuticals in treating mild to moderate depression.

A study in the January 2005 issue of the Journal of Preventive Medicine suggested that a half-hour a day of exercise six days a week is roughly the amount needed to trigger the anti-depressive effect. The study compared two groups of depressed patients and found that the first group, which performed only 80 minutes of exercise a week, received little to no mental-health benefits. However, the second group which logged 3 hours per week of aerobic exercise had a substantial reduction in symptoms. The study concluded that "the response and remission rates in the (three-hours-per-week) group are comparable to other depression treatments, such as medication or cognitive behavioral therapy." It seems to me that runners, who often train far in excess of three hours per week, would obviously derive the full benefits, while the average 3x per week gym rat’s cardio work-out couldn’t deliver the goods.

What no one is really sure of is how it works. There is speculation that endorphins are released during exercise (“runners high”) and that they act as mood elevators. However, studies in the early 1980s cast doubt on the relationship. One study found that when an antagonist was introduced that blocked neuron receptors, the same changes in mood state occurred as when the person exercised with no blocker. So maybe endorphins have nothing to do with it.

Moving forward, a 2003 Georgia Tech study found that runner's high might be caused by the release of another naturally produced chemical, anandamide (a cannaboid) The authors suggest that the body produces this chemical to deal with prolonged stress and pain from strenuous exercise. However, no cognitive effects were observed when it was released so it’s doubtful it has any association with depression.

Just to confuse matters further, in 2008, German researchers using PET scans combined with recently available chemicals that reveal endorphins in the brain, were able to compare runners’ brains before and after a run and discovered that endorphins were indeed produced during the exercise and were attaching themselves to areas of the brain associated with emotions (limbic and prefrontal areas).
Scientists are now suggesting that endorphins work together with epinephrine, serotonin, dopamine and other chemicals to produce the physical and cognitive benefits associated with the runners high and the commensurate decrease in symptoms of depression.

What I was unable to find was a study that looked at what happens when someone using exercise as a depression treatment suddenly stops exercising. I also wonder whether the depression reduction effect turns into something approaching euphoria at the level of the ultra-marathon runner, and whether a sudden cessation of training in the aftermath of a big race has the potential to send the participant into a depression spiral, possibly triggering a suicide attempt. I’ll keep looking.

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