Despite the physical fitness boom, a large proportion of Americans still fail to exercise regularly. In particular, people who begin exercise programs because of an identified health risk are as likely as not to drop out within three to six months. Thus, psychologists have been trying to develop exercise programs that will keep people exercising. As in the case of smoking cessation programs, the encouragement and support of spouses have been found to play a major role in keeping people from dropping out of exercise programs. In addition, people are more likely to continue exercising when they are in a group rather than individual programs. Finally, people are more likely to adhere to a fitness program if they can incorporate the exercise into their daily lives-for example, by walking instead of driving short distances, or by walking up and down a few flights of stairs instead of taking the elevator.