Cycling does the body good.

New data from Tour de France cyclists finds that those athletes live an average of six years longer compared with their counterparts in the general population and die less often from heart-related ailments, damping concerns that extreme, intense exercise increases the likelihood of death from cardiovascular reasons.

The new study, which will be presented Tuesday here at a meeting of the European Society of Cardiology, examined 786 French cyclists who competed in the Tour de France between 1947 and 2012 and the cause of death for those who died over that time.

The data also give limited reassurance that doping with erythropoietin, known as Epo, doesn't appear to dramatically increase the risk of heart attack or early death among elite cyclists--at least in the near term.

The findings offer 'good proof that sports--even if the sport is very, very intensive--among healthy people, without any heart disease, is still beneficial,' said Eloi Marijon, one of the study authors and a cardiologist at the European Georges Pompidou Hospital and Paris Descartes University.

The results 'laid to rest' concerns over exercise intensity with cycling, though the results don't necessarily generalize to marathon running, said Donna Arnett, chair of epidemiology at the University of Alabama at Birmingham and past-president of the American Heart Association, who is chairing the session at which the data will be presented.

Cardiovascular concerns about high-intensity exercise stemmed from a small number of studies on marathon runners, which used advanced imaging ando other measurement tools and found some detrimental signs on the heart immediately after races, prompting some doctors to worry that there may be drawbacks to such extreme exercise.

But those findings were likely normal wear and tear that occurs after strenuousphysical activity when muscles are pushed and a greater volume of blood courses through the heart, and they go away after the body recovers, as some previous studies have shown, said Alfred Bove, professor emeritus at Temple University in Philadelphia and a former president of the American College of Cardiology, who wasn't involved in Tuesday's study.

'Now that we have better windows into physiology, we're beginning to see things we don't understand,' he said.

Such changes may be more easily observed using new imaging and measurement tools. And, many findings about the heart are based on sick patients and shouldn't necessarily be extrapolated to healthy athletes, according to Dr. Bove.

Another question with the study was whether it could shed light on the cardiac effects of doping with Epo, a medication used to treat anemia and other conditions by increasing the number of red blood cells in the bloodstream. Relatively little is known about the long-term effects of doping with Epo, which is used by endurance athletes to enhance their performance by training harder and is banned by the international cycling community in competition. But, when there is an overproduction of red blood cells in the bone marrow, a condition called polycythemia, heart attacks and strokes can result.

It wasn't known which cyclists in the study were using what performance-enhancing substances, so the insight that could be gleaned from the study about Epo was limited.

But, because the use of Epo was thought to be common among cyclists in the Tour de France in the 1990s, researchers expected that if Epo was linked to heart attacks, they would see an uptick in the number of deaths among riders in the past 20 years, as compared with competitors in previous decades, according to Dr. Marijon.

Instead, they observed no difference in the rate of death by decade, suggesting that 'probably there is no strong or immediate association with doping' and heart attack, said Dr. Marijon. He urged caution in interpreting the results and said that more research is needed over a longer period of a time.