For the teens in Dan McGann’s twice-a-week running group, exercise is therapy. That’s not a metaphor: They’ve all been referred to the group by their doctors after being diagnosed with depression or other mental illness. McGann, a therapist, has been leading the program at Trillium Health Partners Credit Valley Hospital in Mississauga since 2006.
“Running is one of the biggest reasons I’m still standing on this earth today,” says Josh Copperthwaite, a 17-year-old who first joined the group two years ago. “When you run you can leave all the bad things in your life behind you – it’s just you and the road. For a few minutes out of the day, you feel free from the weight of depression that clings to your shoulders.”
Researchers have proposed many different theories for how it works. One obvious candidate is the mood-boosting brain chemicals that are produced during and after exercise: Even if you don’t experience the elusive “runner’s high,” there’s little doubt that endorphins, endocannabinoids and perhaps other brain chemicals produce immediate feelings of well-being.
Another possibility is the effect of exercise-triggered growth factors, such as brain-derived neurotrophic factor, which are associated with the growth of new neurons – a key point, since depression is thought to be associated with neuron loss in certain brain areas.