Being physically fit boosts levels of “good” HDL cholesterol and improves the removal of “bad” forms of cholesterol, researchers in Australia report.

HDL cholesterol is known to be the main component of “reverse cholesterol transport” - the removal of “bad” LDL cholesterol from the arteries and its excretion by the liver - but “higher levels of HDL are not necessarily a reliable indicator of enhanced reverse cholesterol transport,” the authors explain in the medical journal Arteriosclerosis, Thrombosis, and Vascular Biology.

“It is well known that regular exercise protects against heart disease,” Dr. Dmitri Sviridov of the Baker Heart Research Institute in Melbourne told Reuters Health. Most likely, there are several mechanisms that account for the benefits of exercise, he said.

One of these mechanisms involves HDL, Sviridov noted.

He and his colleagues compared HDL levels in 25 elite athletes and 33 men who were not athletes but who participated in moderate exercise.

As expected, athletes had higher levels of HDL cholesterol than non-athletes, the researchers report. Athletes also had higher levels of a molecule called apoA-1 that transports HDL.

“We found that ‘good cholesterol’ is enhanced in people who exercise regularly and that may have a protective effect,” Sviridov said. The researchers also uncovered evidence that high levels of fitness are associated with greater efficiency of the process of reverse cholesterol transport.

Sviridov’s team believes that fitness not only promotes production of HDL, but also enhances reverse cholesterol transport.

Although athletes in the study had higher levels of HDL, the difference was not enormous, according to Sviridov.

“You don’t have to be an Olympian to reap maximum benefits,” he said. “Formation of ‘good cholesterol’ in people who exercise regularly without aiming at sporting glory is enhanced almost as much as in professional athletes.”

SOURCE: Arteriosclerosis, Thrombosis, and Vascular Biology, June 2004.