Daily Progress, Charlottesville, Virginia, Jan. 25, 2012

Each Marathoner is Different

The recent encouraging article in the Sunday issue ( Jan 15, 2012) citing a New England J. of Medicine paper, I believe, is somewhat misleading with the concluding statement that since the incidence of sudden death is very low among those participating in marathons it follows that this is a reasonably safe proposition. My concern is this : although the incidence of sudden death during this single event is extremely low might there not be recurring asymptomatic injuries, during or immediately after such events ? Silent ischemia ( an imbalance between oxygen supply and demand ) is a huge problem in Cardiology and provides a rationale for example for performing exercise stress and invasive tests.

Granted we have the genes for long distance running based on the fact that the Navajo, Tarahumara Indians, Bushmen of the Kalahari desert, and the Aborigines all have the capability of chasing an antelope for up to 2 days until the animal drops from exhaustion.

But with my having published in 1992 a LANCET study of Sy Mah , the Guinness Book of Records holder for having completed 524 marathons, free of any cardiac symptoms despite findings at autopsy consistent with permanent injury to the normal heart , I am concerned that prospective marathoners will develop a false sense of security.

Subsequent to my study of Mah and our published study in 1997 of ultramarathoners participating in a high altitude race, there have been numerous publications showing silent injuries to the heart muscle with elevations of a regulatory cardiac protein ( troponin) with marathons; troponin has extremely high specificity for the detection of cardiac injuries.

Finally in my editorial regarding life expectancy studies ( in press ) I have pointed out that determining the right amount of exercise might be more difficult than one might suspect since recent publications of telomeres which provide protection to our chromosomes based on their length ---can be excessively shortened with in turn reduced cell survival from either too much or too little exercise. It seems clear that determining the right amount is not easy.

William J. Rowe M.D.
1485 Bremerton La.
Keswick, VA 22947