In a study spearheaded by Dr. Stanley Nattel of the Montreal Heart Institute Research Center, “Canadian and Spanish scientists prodded young, healthy rats to run at an intense pace, day after day, for three months, which is the equivalent of about 10 years in human terms. The training was deliberately designed to mimic many years of serious marathon training in people.” By the end of the study, these formerly healthy rats exhibited scarring and structural changes in their hearts and were more prone to irregular heartbeats, not unlike in humans. “Interestingly, when the animals stopped running, their hearts returned to normal within eight weeks. Most of the fibrosis and other apparent damage disappeared.”
This study, designed to assess the toll that sustained, intense training takes on a person’s physiology, highlighted exactly what some may find the definition of insane. As Sapolsky on page 123, “sit with a group of hunter-gatherers from the African grasslands and explain to them that in our world we have so much food and so much free time that some of us run 26 miles in a day, simply for the sheer pleasure of it. They are likely to say, “Are you crazy? That’s stressful.”” He also addresses the negative correlation between long distance running and fertility (because of low testosterone and estrogen production) and bone health.
I found this topic worth looking into because, in general, we try to get people to exercise more (if at all) to reap its many physical and psychological benefits, but once in awhile a story breaks of a death during a marathon or debilitating injury from improper training and it’s interesting to see there are some people who find pounding the pavement for 26.2 (or longer!) an enjoyable pastime. More may not always be better, but for whomever wants to wake up early for long training runs dedicate their free time...more power to them!