SCIENTISTS believe exercise helps to clear harmful fatty food molecules from the bloodstream.
Experts who studied 12 overweight and obese men on treadmills found that activity appeared to alter the structure of lipid blood fats.
As a result, it was easier for the fatty molecules to be cleared out of the body.
Lipids are essential to good health, but high levels of some types can cause ill health.
For example, raised levels of the “bad” form of LDL cholesterol increases the risk of heart attacks and strokes.
High cholesterol levels are linked to diets containing large amounts of saturated fat.
Study leader Dr Jason Gill, from the University of Glasgow, said: “We can think of the level of lipids in our blood as being like the level of water in a bath. To reduce the water level you can either turn off the tap, or increase the size of the plughole to let it drain out. For blood lipids this is equivalent to producing less, or breaking them down more.
“Our research suggests that exercise works at the ‘plughole’ end of the process, increasing the body’s ability to break down the fats faster. We think this might occur through structural changes to the lipid particles making them more amenable to clearance from the blood.”
The research is published in the American Journal of Physiology, Endocrinology and Metabolism.
Professor Jeremy Pearson, from the British Heart Foundation, which funded the study, said: “This was a small study, and we need more research to confirm its findings, but it does give us a clue to how some of the benefits of exercise might take place. What’s in no doubt is that being active has very real benefits to our health.
“During the Christmas period many of us indulge more than usual, so it’s vital to balance that with healthy habits - the festive walk is a great healthy tradition for many families. And as the short term drop in lipids lasts for a day or two after exercise, even the last minute dash for presents on Christmas Eve has its benefits!
“Throughout the year adults should aim to be active daily. Over a week activity should add up to at least 2.5 hours of moderate intensity activity in bouts of 10 minutes or more. One way to achieve this is to do 30 minutes on at least five days a week.”