Finding a way to motivate the billion people in the world who are overweight to lose excess pounds can be an overwhelming task, but a University of Houston professor is meeting that weighty challenge with a challenge of his own.

Ioannis Pavlidis, a UH computer science professor, and research assistants Yuichi Fujiki and Kostas Kazakos, have developed a computer game that translates physical activity into video games, such as races and logic puzzles. Dubbed Non-Exercise Activity Thermogenesis (NEAT-o) games, they can be played on any hand-held personal digital assistant (PDA) with users wearing a lightweight, wearable sensor that detects movement like running, walking, bending over or even foot tapping.

That data is then transmitted to the PDA via a wireless connection, and the player can see his or her game avatar move in real-time to their movements. For example, in the race game, the player's physical activity propels the avatar around the track -- the more active the player is, the faster and farther the avatar goes.

"When you see the avatar move when you move, you really become connected to the game," Pavlidis said.

Capitalizing on the buddy system for working out, users can link to other gamers by cellular phone networks and compete against multiple users in the next cubicle or the next state. The game can run all day in the background as users go about their daily routines while earning points and propelling their avatars as they walk to the copy machine, take coffee…