The biggest hurdle: finding the motivation to get off the couch

Developing the motivation to exercise is one of the most important keys to a healthier lifestyle. Peter Crocker, an expert in sports and exercise psychology at the University of British Columbia in Vancouver, says motivation is the most important factor in exercise because it determines which activity you choose to do and why you maintain it over time.

The key is to find an activity you enjoy and to stick with it. People who feel they have to exercise - perhaps on a doctor's orders - are more likely to drop out of physical activity than people who exercise because they find it pleasurable.