According to recent American research, there is still hope for the couch potatoes.

A study conducted by Dr. Timothy Church, director of the Laboratory of Preventive Medicine Research at the Pennington Biomedical Research Center at Louisiana State University, shows that even with just half of the recommended daily exercise dose, a substantial and immediate benefit in cardiovascular health can be attained.

The research published in the Journal of the American Medical Association, was conducted by involving post-menopausal women who led a generally sedentary life.

Around 464 such women, considered obese or overweight, and with some degree of high blood pressure as well, were divided into three groups and a control. The control group was not allotted any exercise, while the others received 50 % (72 minutes of exercise per week or 10 minutes daily), 100 % (136 minutes/week) and 150 % (192 minutes/week) of the recommended exercise dose. This is fixed by the National Institutes of Health as 30 minutes of moderate exercise per day.

When the researchers measured the women's peak oxygen consumption at the start of the study, and then again after six months of exercise, they found that the women in the light exercise group increased their peak oxygen consumption levels by 4.2 percent. The moderate exercise group saw a 6 percent rise, while the heavy exercise group upped their cardio-respiratory fitness by 8.2 percent.

Says Church:"This is great news for couch potatoes and for the aging.

"There are people that can't obtain the recommendations for exercise, but now, we see if you can't get 150 minutes a week, you stand to benefit even if you get half that."

Co-author I-Min Lee was quoted: "These findings suggest that different outcomes may show different responses. Even with a little bit of physical activity, there was a significant improvement in physical fitness. And, this study showed that as the dose increased, you saw commensurate increases in fitness.

"With a very doable dose of physical activity, you can start seeing health benefits," Lee added.

According to health statistics, more than one third of the US population is overweight, and 60 million US adults are obese.