Exercise Lowers Cholestero

Researchers aren't entirely sure that how exercise lowers cholesterol, but now they are beginning to have a clear idea. "Lots of people, even lots of doctors, assume that exercise lowers cholesterol," says Amit Khera, MD, director of the University of Texas, Southwestern, Medical Center's Program in Preventive Cardiology. "But until recently, most of us weren't sure just what the connection was."

One way to exercise can help lower cholesterol is by helping you lose -- or maintain -- weight. Being overweight tends to increase the amount of low-density lipoprotein (LDL) in your blood, the kind of lipoprotein that's been linked to heart disease. Part of the confusion about the effect of exercise on cholesterol results from the fact that most early cholesterol studies focused on both exercise and dietary changes, making it hard to make out which of these factors was actually making the difference. But recent studies have more carefully examined the effect of exercise alone, making it is easier to evaluate the relationship between exercise and cholesterol. Researchers now believe there are several mechanisms involved in it. Firstly, exercise stimulates enzymes that help move LDL from the blood (and blood-vessel walls) to the liver. From which, the cholesterol is converted into bile (for digestion) or excreted. So the more you exercise, the more LDL your body expels.

Second, exercise increases the size of the protein particles that carry cholesterol through the blood. (The combination of protein particles and cholesterol are called "lipoproteins;" it's the LDLs that have been linked to heart disease). Some of those particles are small and dense; some are big and fluffy. "The small, dense particles are more dangerous than the big, fluffy ones because the smaller ones can squeeze into the [linings of the heart and blood vessels] and set up shop there," says Khera. "But now it appears that exercise increases the size of the protein particles that carry both good and bad lipoproteins."