Researchers in the U.S. say that just 10 minutes of exercise a day can help even the most inactive overweight women.
This will be a relief to many women who are over-whelmed by the dogma which dictates that exercise must be an all or nothing affair to offer any physical value.
The researchers at Louisiana State University, Baton Rouge, led by Dr. Timothy Church, conducted tests on overweight and obese women, many of whom had high blood pressure.
They found that even small amounts of exercise improved their fitness and toned them up enough to lower their overall risk of early death.
The study is the first to reinforce with concrete medical data that exercise does not have to be an all-or-nothing venture and Dr. Church says the information should be used to encourage sedentary adults to find the time for some activity each week.
While everyone knows that exercise is good for you, 20 percent of U.S. adults admit they do no exercise whatsoever and most do not get as much as is recommended.
The U.S. Centers for Disease Control and Prevention and National Institutes of Health recommend at least a half hour on most days, of moderate exercise to reduce the risk of heart disease, stroke and cancer.
The Institute of Medicine, which advises the federal government, says people need to get themselves slightly out of breath for closer to an hour every day.
Dr. Church and his colleagues wanted to see whether women overwhelmed at the idea of that much work might be helped by something they consider a little more manageable.
The study involved 427 overweight women with high or borderline-high blood pressure with an average age of 57.
The volunteers were randomly assigned to continue their normal lives or to exercise 75 minutes a week, 135 minutes a week or 190 minutes a week, tying in with the NIH and CDC recommendations and providing half as much as recommended, and 150 percent of what they recommend.
The women walked on treadmills and rode stationary cycles, but other activities of a similar intensity to brisk walking would equate.
Although after a six month period the women on average had not lost any weight and their blood pressure, as a group, had not changed, all the women who had exercised were fitter, as measured by oxygen intake as they exercised and their waists were smaller.
Waist circumference is significant as an important indicator of health risk as women with waists bigger than 35 inches (90 cm) and men whose waists are bigger than 40 inches (100) have a documented higher risk of early death.
The report is published in the Journal of the American Medical Association.