Posted: January 23, 2005

Multisport: Ultra Endurance Exercise - Too Much of a Good Thing?

When it comes to exercise we live in a world of extremes. The state of fitness of humans is at an all-time low. At the other end of the spectrum, however, we may be heading off the deep end. There is a rapidly increasing number of participants in ultra events from adventure races to ironman triathlons and beyond. Is this too much of a good thing?

The benefits of regular moderate exercise include a reduction of cardiovascular risk factors, slowing the aging process, improving functional capacity, and improving mental health and well-being.

Taken to excess, however, exercise has a down side. In a study of Harvard Alumni by Stanford University's Ralph Paffenbarger, he found that death rates were lower for men who were involved in regular physical activity. The death rate declined with an increase in the number of calories burned in physical activity up to a point. Death rates began to go up slightly among men expending in excess of 3000 extra calories per week. Excessive exercise can backfire on you," says Dr. Ken Cooper, a physician who heads the Cooper Institute for Aerobic Research in Dallas Texas, and the father of "Aerobics". Cooper argues that there appears to be a point of diminishing returns where your immunity is adversely affected and you break down your resistance to infection and disease. "[How much is too much] varies according to the fitness level of the individual", Dr Cooper said.

There are a growing number of "exercise addicts" who exercise beyond the point of reason and who have put their need for exercise ahead of a balanced lifestyle.

In a Health and Body column New York Times writer Andre Taber wrote "American athletes tend to be an obsessed bunch, but the trend toward endurance extremes has sounded alarms in the medical community. In the short term, common consequences of prolonged, strenuous exercise include tendonitis, stress fractures and chronic fatigue syndrome. But research is beginning to show that by racing ever farther and longer, athletes may also be putting themselves at risk for a host of chronic diseases, even cancer."

Liz Applegate, Ph.D., a nutrition professor at UC Davis, is not surprised at the news that extreme athletes may be compromising their health. "People can do it," Applegate says, acknowledging the feats of athletes like Mark Allen -- a greyhound of a triathlete who has captured the Hawaii Ironman six times -- "but the body wasn't meant to do it." "There are a bazillion stories of athletes who have developed chronic fatigue syndrome," says Applegate, singling out overtraining as the most common ailment among the ultra-athlete set.

Studies have shown that high intensity resistance exercise increases free radical (unstable molecules) production. Endurance exercise can increase oxygen utilization from 10 to 20 times over the resting state. A free radical can destroy a protein, an enzyme or even a complete cell. To make matters worse, free radicals can multiply through a chain reaction mechanism resulting in the release of thousands of these cellular oxidants. When this happens, cells can become so badly damaged that DNA codes can be altered and immunity can be compromised. Natural antioxidants like vitamins C and E (which are prevalent in fruits and vegetables) combat oxidative damage, and are abundant in most healthy eating habits. Under moderate strain, the body's biology can easily adapt, activating its stores of antioxidants and extinguishing "oxygen fires," as Applegate calls them. According to her, when an athlete repeatedly pushes him or herself through prolonged exhaustive training sessions, the body can no longer keep up.

"There are red flags all over that the immune system is under stress and not performing well," said Dr. David Nieman, a former marathoner who studies extreme exercise as Director of the Human Performance Laboratory at Appalachian State University. "Some immune cell functioning is down for hours. Some is suppressed for days."

While it is not currently possible to draw a link between extreme athletics and cancer, molecular tests have proven the effects of oxidative damage. Prentice Steffen, the physician of the Mercury professional cycling team, doesn't dismiss the theoretical possibility that cancers in athletes like Lance Armstrong -- an American cyclist who developed testicular cancer in October, 1996, but has since recovered and returned to competition -- could have had their genesis in over-exercise. Growing evidence suggests that an athlete caught up in an ultra-distance addiction is accelerating the aging process, and Steffen contends that ultra-athletes need to become proponents of moderation. "Anything in the extreme is not good," he says. "The body and its joints only have a certain lifetime." "They're using up too much too soon."

Source: Ken Parker

This article originally appeared in Ottawa Outdoors Magazine