7 Hours a week, sufficient exercise for healthy body

The battle for the bulge just got tougher. Women need to get at least an hour a day of moderate exercise if they hope to ward off the creep of extra pounds that comes with ageing, American researchers have said.

The 420 min-solution

The weekly total of 420 minutes is nearly triple the 150 minutes of moderate daily exercise currently recommended by US health officials and illustrates the challenge women face in maintaining a healthy weight.

Winning that war will require individuals to make changes in their daily routines -- like walking or biking to work -- but it may also take a shift in policy to make it easier for people in fit exercise into their lives, researchers said.

"From a public health perspective, it would be better to prevent the weight gain in the first place," said I-Min Lee of Brigham and Women's Hospital and Harvard Medical School in Boston is reported to have said.

The study

Lee's team studied the guidelines in more than 34,000 healthy US women with an average age of 54 who ate a typical American diet.The women reported their weight and weekly exercise totals in the first year, and then at three-year intervals from 1992 to 2007.

Over the course of the study, the women gained an average of 5.7 pounds (2.6 kg) overall. Only 13% of women in the study maintained a healthy weight throughout the study -- and those who got an hour of exercise a day on average or more were by far the most likely to be in that group.

"Only in this group of women did we find physical activity was associated with less weight gain," Lee said. For the heaviest women, no amount of exercise helped, they found. They needed to diet, also.

Lee said the results suggest that the current recommendations of two and a half hours per week are not enough to keep middle-aged women from gaining weight as they age. Lee said women should not let the findings discourage them from exercising at all, but they may want to make small changes now to prevent later weight gain.

Hike and bike to keep off those inches

"I think the easiest thing is actually commuting," she said, suggesting people walk or bike to work, and if they drive, to park farther away from the office. If 7 hours a week are just too hard to fit in, Lee said people might want to consider vigorous exercise such as jogging, which can cut the weekly time requirement in half.

And she said policymakers need to consider changes that make it easier for people to exercise, such as building sidewalks or bike lanes that make it easier and safer for people to exercise.