There's some evidence that believing you are exercising produces the same healthful results as exercising:
Four weeks later, the researchers returned to assess any changes in the women's health. They found that the women in the [group that believed they were exercising] had lost an average of 2 pounds, lowered their blood pressure by almost 10 percent, and were significantly healthier as measured by body-fat percentage, body mass index, and waist-to-hip ratio. These changes were significantly higher than those reported in the control group and were especially remarkable given the time period of only four weeks.
I've often wondered, while watching an exciting sporting event on the T.V., whether my elevated heart rate constituted a healthy cardiovascular activity, despite the fact that I was doing nothing more than sitting on my ass. It now appears that, at worst, so long as I believe that it's a healthy activity, I can enjoy the benefits of the healthy activity along with a bag of blue corn chips and high O.G. beer.