(CHICAGO) -- Women may be the lucky ones when it comes to keeping the middle-age weight off -- if they put in the work.
A new study from Northwestern University researchers found that although everyone gained weight as they got older, men and women who regularly exercised gained less weight over time than those who did not. Women, especially, gained less weight when they made exercise a habit.
"Stay active," said Dr. Arlene Hankinson, an instructor in the department of preventive medicine at Northwestern University Feinberg School of Medicine. "It's not just achieving a high level of activity. The difficult part is maintaining that level throughout your life."
More than 3,500 adults from four major cities took part in the 20-year study. Inactive women gained about 13 more pounds than those who were active. Sedentary men gained only about six more pounds than their exercising counterparts.
To measure results, researchers asked study participants questions on how often they undertook 13 different moderate to vigorous activities, including sports, jogging, housework and construction.
The highest activity levels were defined as 150 or more minutes per week of exercise.
The authors also noted that people who reported moderate or inconsistent activity levels generally had a similar outcome to those who reported low daily activity.
"It's important to understand that the type of activity is probably not as important as the moderate to vigorous intensity and how often someone is doing it," said Hankinson. "You don't have to look for a dramatically high intensity of activity as long you're able to maintain it."
Dr. Robert H. Eckel, professor of medicine, physiology and biophysics at the University of Colorado Denver Anschutz Medical Campus, said it was important to cite the difference between the effects of diet and exercise.
"Losing weight is diet (caloric intake), whereas prevention of weight gain is more physical activity," Eckel wrote in an e-mail. "I'm not sure what to make of the male-female difference, but [it] might have something to do with that group of women who are committed or obsessed with maintaining their shape and weight."
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