Another warning about endurance training

It’s not clear what defines “vigorous” when it comes to endurance training, but another team of researchers is putting the brakes to working out more than 60 minutes at a time.

On its website, the CBC reports on a scientific review published in the Mayo Clinic Proceedings, which suggests that benefits of vigorous exercise diminish after an hour, and may even cause cardiovascular events. The piece, which quotes author Dr. James O’Keefe from Missouri,  suggests that some endurance athletes could be doing damage to their hearts:

“When people come to me as a cardiologist and say they want to run a marathon I say, ‘OK, do one and cross it off your bucket list and then let’s focus on an exercise pattern that’s more ideal to producing long-term health benefits and improving your longevity,'” O’Keefe said.

People who exercise regularly have lower rates of disability and a life expectancy seven years longer on average than couch potatoes, the researchers noted.

O’Keefe wants people to understand that the lion’s share of benefits come at a relatively modest level. No further benefits are obtained beyond 30 to 60 minutes a day of vigorous activity.

The researchers said elite-level athletes commonly develop abnormal electrocardiograms and their hearts adapt in ways that traditionally weren’t thought to be harmful. Now it seems the cardiac remodelling from excessive exercise can increase their risk of heart rhythm problems like atrial fibrillation.

After people reach their mid-40s, long and intense exercise can cause scarring and fibrosis in the heart, O’Keefe said.”

The ultra running world took notice this winter when Micah True died while running a 12-miler.  The author of Born to Run , known as the Caballo Blanco, died when the rhythm of his heart went of control. He would sometimes run a 100-miles a day,  and some people blame running for his death at age 58.

His is an extreme case, but combined with the perception of increasing number of deaths at marathons, people want to know more about what could be “excessive” when it comes to endurance training and the heart.