According to WebMD, exercising with the Wii is not a fully balanced fitness program and does not replace going to the gym, but for many people, it provides a good start. Additionally, the Wii's ability to help someone get fit depends primarily on which exercises the individual chooses to do using the Wii.
Wii Fit exercise programs focus on balance, yoga, strength training and aerobics. While balance is a key component of core stability, the balance exercises available on the Wii do not reflect actual fitness, notes WebMD. The biofeedback element of the yoga exercises measures proper weight distribution and steadiness, but many yoga practitioners would probably consider the exercises inadequate. WebMD also states, that although both the strength-training and aerobics programs begin with a very low level of cardiovascular exercise, they do allow the user to progress and advance.