By Dr. Mercola
In the TED talk above, Dr. James O'Keefe, a research cardiologist and a former elite athlete, discusses an important point that can be difficult for some to accept, namely the fact that extreme cardio can actually do more harm than good...I am about two years older than Dr. O'Keefe and had a similar running history. Dr. O'Keefe actually won the largest sprint distance triathlon in Kansas City five years in a row, from 1999 to 20041 .Although I was never an elite athlete like Dr. O'Keefe, I had run a 2:50 marathon previously. It is satisfying to hear Dr. O'Keefe validate what I have been writing about for years now. I suspect we both wised up and stopped running at about the same age, after many decades of intense endurance training.The myth that extreme endurance cardio is good for your heart took off at full speed when, in 1977, Dr. Thomas Bassler boldly proclaimed that "completing a marathon confers immunity against heart attack." Many die-hard runners still believe this to be true.However, in the years since, research has shown that the complete opposite may be true2. According to one study, presented in the video above, once you reach 40-50 minutes of vigorous exercise per day, the benefits from your efforts plateau, and further efforts do not convey further improvements in life expectancy.When it comes to light to moderate exercise, on the other hand — such as walking, housework, and similar less strenuous day-to-day activities — more isbetter. It's not as effective as vigorous exercise (performed less than about 40 minutes a day), but the more active you are throughout the day, the better your life expectancy.
Survival of the Moderately Fit
As Dr. O'Keefe says, "Darwin was wrong about one thing. It's not survival of the fittest, but survival of the moderately fit." If you can dance, or lightly swim, or jog at six miles an hour, your mortality rate plummets compared to someone who can barely walk a flight of stairs. However:"Further attainments of peak fitness do not translate into further increases in life expectancy. It plateaus out," Dr. O'Keefe says. "We weren't born to run. We were born to walk, and we need to be walking more... you need to be moving your body more than sitting — every chance you get, move! "