Tuesday, June 30, 2009

Quit smoking (and junk food?) through brief exercise?

Brains are crazy places.

So neuroscientists using fancy brain imaging (fMRI) devices have demonstrated that nicotine stimulates the brain's mesocorticolimbic system (a reward centre).

Other research has demonstrated those same centres lighting up with food cravings.

Old news, no?

Sure, but new fMRI studies combining smoking cues with exercise may help to explain how exercise helps with weight loss.

Now most people believe exercise's role in weight loss is purely mathematical - it burns calories. While indeed that does play a role, unfortunately exercise doesn't burn nearly as many calories as would be fair and really is generally a minor mathematical player in weight loss. Yet despite it's minor role there's a robust evidence base that suggests exercise is essential in weight management, especially weight maintenance.

So how does it help? If it doesn't burn many calories, what exactly does it do to help with weight control?

Perhaps it changes your brain.

You see a recent study published last year in the journal Psychopharmacology demonstrated that smokers who were nicotine abstinent for 15 hours, when faced with images of smoking had their mesocorticolimbic systems light up like Christmas trees. Yet Those same smokers, when exposed to 10 minutes of exercise prior to the smoking images showed no such lighting.

So could the role of exercise in weight management have more to do with craving control than burnt calories? Do the folks who exercise more effectively turn off the parts of their brains that at times make cravings irresistible?

Only one way to find out. If there's a time of the day that's more difficult for you to manage cravings why not try to build in 10 minutes of brisk walking, gardening, stationary biking, dance or active play and see if it helps to take the edge off? Worst case scenario? You get 10 extra minutes of healthy exercise.

Janse Van Rensburg, K., Taylor, A., Hodgson, T., & Benattayallah, A. (2008). Acute exercise modulates cigarette cravings and brain activation in response to smoking-related images: an fMRI study Psychopharmacology, 203 (3), 589-598 DOI: 10.1007/s00213-008-1405-3