Fitness apps that take a more social tack also are available. Teemo, Nexercise and Fitocracy all allow you to post your latest workout to share with friends. Some games have you work with friends to reach a common goal -- completing a relay race, for example -- while others encourage competition.
"That's another big area, having that social component," Matthews said. "Having social support of some kind is a critical factor in adhering to an exercise program. For some people, having that friendly competition or the feeling of being on a team can help them stay motivated."
What's more, the apps either are free or available at a minimal price of $2 to $4. Zombies, Run! is the most expensive at $7.99 for two "seasons" worth of episodes.
Donna Arnett, president of the American Heart Association, said there's good evidence already that gadgets like accelerometers can prompt interest in physical activity.
"I know when my accelerometer says I have 3,000 more steps to go to reach my daily goal, that motivates me," she said. "I would think the apps would work the same way. Anything we can do to motivate people is a good thing."
Dr. Stephen Ponder, an American Diabetes Association spokesman, said it remains to be seen whether these fitness games will have a lasting impact or prove a passing fad.
"If there are ways to use those devices to get people to move, I think that has a lot of potential," said Ponder, a pediatric endocrinologist in Temple, Texas. "The question is, can you see yourself using this indefinitely or would it need to change and morph and you'd need to have different games to keep your interest? For any kind of health technology, it needs to be something that people will put up with and use for an extended period of time."