Running, Evolution & Health

After I heard about persistent hunting, and how early humans used their ability to regulate body temperatures (through sweating) as a competitive advantage in hunting; I thought running is part of our genetic code, and that every one of us can run long distances.

I also believed that running and exercise are good for health, and I used to spend 2 hours a day in the gym burning 800 to 900 calories a day (4 miles of running, 6 to 10 miles of cycling, and 30 minutes of weight-lifting - four days a week). I used to feel good about my health during these periods of exercise (possible runner's rush). It has been a while since I ran that long, and feel guilty these days for bowing to worldly pleasures and not going to the gym.

But, I came across a couple of articles over the past few weeks that made me re-think about both of these assumptions, and gave me a reason to maintain the statusquo (running vs. sitting on the couch - it is an easy choice I guess :)) :

Here are the data points I am talking about:

• Recent deaths of marathoners: Detroit (3 deaths), San Jose(2 deaths), NY (2 deaths) - in all the these incidents, the runners who died went through rigorous training for the event. While 7 deaths is a very small percentage of the millions who run marathons (statistically insignificant to draw any conclusions), it still is something to think about (psychological impact) for a would-be marathon runner. (Imagine a gamble with the following payoffs - you will win $1 mil 99.9% of the time,  you will lose & die 0.1% of the time - will you play that game?)
• A blog in NYT (14th Oct, 2009) talks about how intense exercise reduces our immunity: The article cites studies done by multiple research groups about the relationship between exercise and immunity - and concludes that intense exercise (defined as a workout or race of an hour or more during which your heart rate and respiration soar and you feel as if you are working hard) can significantly reduce your immunity; and that you are better off doing something productive (like watching TV) than running.

I guess - after thousands of years of relative-sedentary life style of the agrarian societies, running is no more an evolutionary in-thing; and it is possible mate-selection is not happening based on good running abilities.