A new study has good news for people who've been avoiding exercise because I they don't think they have enough time—even 10 minutes a day can improve cardiovascular fitness.
The research found that when overweight or obese, sedentary women started to exercise an average of 72 minutes a week, they increased their peak oxygen consumption-a measure of cardiovascular fitness—by 4.2%.
"It was surprising to us, the idea that as little as 10 to 15 minutes of exercise a day could provide benefit in terms of fitness," said the study's lead author, Dr. Timothy Church, director of the Laboratory of Preventive Medicine Research at the Pennington Biomedical Research Center at Louisiana State University.
Church noted that the intensity of exercise the women in the study engaged in was very low, probably equivalent to walking at a speed of about two to three miles an hour. "For people who've been really sedentary, you're getting a benefit almost immediately. Just get off the couch," he added.
The researchers also found that while a little bit of exercise was beneficial, more exercise boosted cardiorespiratory fitness even higher.
"Physical activity is clearly beneficial for your health. This study shows that any activity is good, and more is better," said Dr. I-Min Lee, an associate professor of medicine at Brigham and Women's Hospital and Harvard Medical School, both in Boston.
Church and colleagues undertook the research, because there have been few studies that have looked at the dose-response effect of exercise-that is, how much exercise do you need to see a benefit and will more exercise continue to produce additional benefits?
To answer those questions, the researchers recruited 464 overweight or obese postmenopausal women. All of the women had some degree of high blood pressure, and none exercised at all.
The women were randomly assigned to one of four groups: The control group that remained sedentary; a light exercise group that averaged 72 minutes a week of exercise, a moderate exercise group that averaged about 136 minutes a week; and a high exercise group that completed nearly 192 minutes of exercise each week.
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%. The moderate exercise group saw a 6% rise, while the heavy exercise group upped their cardiorespiratory fitness by 8.2%.
“This is great news for couch potatoes and for the aging," said Church. People who can't do the recommended amount of exercise each week can still benefit from a smaller amount.
Current recommendations call for 30 minutes of exercise most days of the week. Church said the three exercise groups roughly translate to 50%, 100% and 150% of the exercise guideline.
"Even with a little bit of physical activity, there was a significant improvement in physical fitness. And, this study showed that you can start seeing health benefits, with a very doable dose of physical activity," he said.