In 2008, the federal government released exercise guidelines recommending that adults exercise 150 minutes a week. And for many busy women around the country, the concept of exercise a half hour five days a week seemed doable. But a new study published in the Journal of the American Medical Association suggests that for women to maintain a healthy weight, they need to exercise 60 minutes a day. And some fitness experts worry that this study may actually deter women from exercising at all. "While there are so many wonderful reasons to exercise, for many women, weight loss is a primary motivator. And if they think it won't help, it's just one more excuse to not do it," explains Michele Stanten, fitness director for Prevention magazine.
THE DETAILS: Researchers tracked nearly 35,000 women (average age 52) over a 13-year period, trying to determine how much exercise is needed to prevent weight gain. Throughout the study, researchers checked in to analyze participants' BMI and query them on physical activity levels.
Physical activity levels were associated with less weight gain over the 13 years of the study, but only among women of normal weight. Harvard researchers also found that the women who were successful in maintaining a normal weight averaged 60 minutes a day of moderate-intensity activity throughout the course of the study.
WHAT IT MEANS: Before you throw up your hands and give up on staying fit, a few reality checks are in order. "This is just one study, and no study is perfect," says Stanten. For instance, this study relied on individual reports of physical activity at five times during the 13-year period. "Researchers do their best to ensure accuracy, but some people may overestimate how active they are. And the researchers can't be sure that the women maintained their activity levels in between reporting." Also, the study didn't take eating habits into account; women who both exercise and eat healthy diets may need less exercise to maintain or lose weight. "Bottom line: This study is not the final word on weight loss or maintenance. It's a piece of the weight loss/maintenance puzzle," says Stanten.
Don't freak out over the study, but do find ways to get more motion into your life. Here are some options:
• Get moving first, add up the minutes later. Focusing on 60 minutes versus 30 minutes misses the point: Exercise as much as you can. "Don't stress out about another number, and definitely don't give up on exercise—there are too many other benefits to reap from it," says Stanten. (They include lowering your risk of cancer and many chronic diseases that can shorten your life.) If you don't exercise, start by incorporating physical activities and exercises you like into your day so you'll stick with a program. "Once you start to see the benefits and get in the habit, you'll likely do more," says Stanten, who recommends that people already exercising less than an hour a day add an extra five or 10 minutes at a time.
Read on to find out other ways to boost weight loss.
• Pay attention to NEAT. Stanten says another component of the weight-loss/weight-maintenance puzzle that is just starting to be talked about more involves "non-exercise activity thermogenesis," or NEAT. "Thanks to new research from James Levine, MD, PhD, professor of medicine at the Mayo Clinic, we're learning that the activity we do throughout the day, outside of traditional exercise, can have a big impact on our body weight. And this study did not look at this component."
NEAT includes ways you stay active throughout the day by doing things like taking the stairs, parking farther from a destination, and getting up from your desk every hour or so.
• Bring your diet into the equation. "Remember that we don't exercise in a bubble," says Stanten. "Your diet impacts your weight. Research also shows that sleep has an effect, and stress is also involved."
"The most important thing that people should take away from this is that most Americans need to be more active, and that in trying to maintain a healthy weight, you can't ignore your diet," says Stanten. "Most of us are too busy to fit in an hour of exercise a day, so you have to also watch what you eat."