Pictured above is Ed Whitlock. He currently holds the world record in men’s marathon times 70-74, 74-79 and over 80. At the age of 70 he completed a marathon 2:59:10, at 73, 2:54:48, at 76, 3:04:54 and at 81 he recorded a time of 3:15:54. With the coming wave a baby boomers, we should expect to see more older aged participants. What can we expect with them?
As discussed previously (here), the media plays on the fact that during extreme endurance events, some participants have cardiac events and need to be rushed to a hospital and unfortunately, some even die. We’ve clearly demonstrated that this approaches 0.001% of the population of participants in marathons.
Karlstedt et al 2012 surveyed a different population which is much more relevant to the question if extreme endurance can cause cardiac events. He and his team surveyed 25 men mean age 55+/-4years who had no known heart condition and had participated in at least 3 marathons in the last 2 years.
The subjects were measured 1 week pre-race, immediately post-race and 1 week post-race. Measures included height, weight, resting heart rate, resting BP, myoglobin, creatinine kinase and cardiac specific troponin T, and echocardiogram, cardiac computed tomography and cardiovascular magnetic resonance.
Immediately post-race the sbujects’ resting heart rate and pulse were elevated but not significantly. Myoglobin, CK and cTnT on the other hand were all P<.05 higher after the race. The echocardiogram showed changes in the Lateral E and A segments of the left ventricle. The right ventricle had changes in the S, E and A at the base.
It is important to note that all of these changes had returned to normal 1 week post-race. The authors discuss how their data indicates that post-race myocardial fibrosis (detected by late gadolinium enhancement) in marathon participants occurs at 3 times the rate of age-matched controls; 42% demonstrating normal LGE patterns while 58% demonstrated an atypical pattern.
More research needs to be done especially given the rising age of the baby boomers and their continuing desire to participate in fitness events. That said, a knowledge that many of them are increasing their myocardial fibrosis rates gives us a place to start when discussing their training and future treatments.