BOSTON — While 91 percent of the respondents to a recent survey believe exercising at a health club would improve their overall health, only 18 percent of those surveyed actually belong to a health club, according to a survey by the International Health, Racquet and Sportsclub Association (IHRSA).

Lack of time is the leading reason more Americans don't exercise and go to health club, the survey found. Forty-two percent of respondents said that exercising for 30 minutes twice a week at a health club would interfere with other priorities while 34 percent said it would not.

According to the Centers for Disease Control and Prevention, two-thirds of American adults do not engage in regular leisure-time physical activity. John McCarthy, former executive director of IHRSA, said understanding why most Americans don't exercise is the first step towards helping them improve their health and fitness.

“What needs to change so more people can make physical activity a routine part of their daily lives?” McCarthy said. “We must understand the barriers to increased physical activity and act now to counter the health crisis our country is facing. Somehow, we must make the cultural shift from a sedentary to a more physically active society.”

Support from family for an exercise regimen also plays a factor. Nearly half of the married Americans who responded to the survey said their partner or spouse didn't want them to exercise twice a week for 30 minutes while 34 percent supported their twice-a-week visit to the club. Half of the respondents with children said their children didn't think they should exercise twice a week at a club while 19 percent thought they should go to the club two days a week.

Only 40 percent of Americans surveyed believed their doctor thought they should exercise at a health club at least twice per week for 30 minutes for the next month.

“It's extremely surprising that although regular physical activity is such a fundamentally important component of good health, so many people don't understand that their doctors want them to exercise — and only a minority of Americans feel they have their family's support in establishing healthy lifestyles,” McCarthy said.