How Much Should You Exercise?

Members exercise at the Maryland Athletic Club and Wellness Center in Timonium, Md., AP

In January 2005, the U.S. government released a new set of dietary guidelines essentially telling us that as Americans get bigger, so does the length of time we need to be physically active.

While it's a little more involved than that, the guidelines from the Department of Agriculture and the Department of Health and Human Services indicate that at least 30 minutes of daily physical activity is required to reduce the risk of chronic diseases in adulthood. And for some, that's only the beginning.

"The dietary guidelines committee primarily focused on the role of physical activity in influencing energy balance and weight status," says Russell Pate, PhD. Pate was a member of the dietary guidelines advisory committee.

"We felt that it was important to reaffirm the 30 minutes of exercise every day guideline as applicable to all adults," says Pate, "but also go beyond that and focus on people who tend to gain weight anyway even if they are meeting that 30-minute threshold."

Thirty minutes of exercise every day? And in some cases, even more? While it might not be music to your ears, it is health to your body.

"Poor diet and physical inactivity, resulting in an energy imbalance (more calories consumed than expended), are the most important factors contributing to the increase in overweight and obesity in this country," according to the guidelines.

Going Beyond the 30-Minute Threshold

It's not like we haven't heard it before: Exercise is an essential part of the health equation, and 30 minutes a day is where it begins.

"Thirty minutes of physical activity is across the board to all adults, every day of the week," says Pate, who is a professor at the Arnold School of Public Health at the University of South Carolina. "There is enormous scientific information to support this."

Meeting the 30-minute threshold will help a person maintain a healthy weight and reap health benefits like lowering the risk of heart disease, osteoporosis, diabetes, and hypertension, according to the guidelines.

From there, the amount of physical activity a person needs climbs, depending on his weight status.

"For those who are following the 30-minute guideline and gaining weight anyway, they may need as much as 60 minutes a day to prevent weight gain," says Pate.

And at the high end of the spectrum is 90 minutes of exercise every day.

"The 90-minute recommendation is for people who have been significantly overweight, lost a substantial amount of weight, and seek to maintain that weight loss in the long term," Pate tells WebMD. "Data from the National Weight Loss Registry indicates that people who have been overweight succeed in losing and maintaining weight loss for an extended period if they are highly active during the period when they are maintaining the loss."

Ninety minutes is the bottom line for people in this category, although some might comment that most people aren't even doing 30, so why would they do two or three times that?

"It looks different, and dramatic and potentially controversial," says Pate. "But whether you like the facts or not, it's important to base the recommendation on the best science available."

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