Friday, 19 December 2014

Why don’t sumo wrestlers die of heart disease?

by Dov Michaeli

How many of you watched a sumo wrestling match? I’d bet not too many. Let me tell you—it is absolutely fascinating, but for reasons that have nothing to do with the sport per se. The rules are very simple, almost childish. Two wrestlers face each other in a circle and push and shove attempting to have the opponent step outside the circle boundary. It reminded me of a game I used to play in elementary school, where two kids, hopping on one leg were pushing on each other trying to have the opponent land on both feet.
There were two things that fascinated me about the sumo match I saw in Tokyo.

The ritual

Sumo goes back hundreds of years in Japanese culture, and has its roots in ancient religious rituals. Coming to think of it, the classical Greek Olympic Games were also part of religious rituals.
When the two sumo wrestlers get into the arena they launch into an elaborate “dance”, bowing and embracing each other. Being the cynical Westerner that I am, I thought all this display of respect a bit phony; why can’t they just get down to business without wasting time on archaic rituals? My Japanese friend set me straight. These rituals are very meaningful to modern Japanese spectators just as they were to ancient ones. They connote the philosophy that being civil to each other cannot be checked out at the door even when one is going to engage in fierce combat. In one of the matches a Croatian wrestler who apparently was ignorant of the importance the Japanese attach to the ritual, went through the motions without conviction; a murmur of disapproval wafted through the audience.
The other ritual is just as interesting. Both wrestlers cast salt on the circle’s ground. Even my Japanese friend was at a loss explaining its meaning. I later found out that, like in virtually all cultures, salt held great importance and was a symbol of well-being and friendship. Hence the custom of greeting with bread and salt. And hence the expression “salt of the earth”. What the wrestling ritual meant was probably both: an homage to the opponent as “salt of the earth”, and wishing him (there are no female sumo wrestlers, yet) prosperity and well-being. But enough of obscure rituals; this is a health blog.

The other fascinating thing

I was watching those grotesquely obese behemoths (400 lbs is considered light weight) and wondered what awaits them when their career would be over in a very few years. Are they all going to get type 2 diabetes? Is their mortality rate due to heart disease astronomically high?
To put things in perspective—these wrestlers are not fat slobs, they are just fat. In medicine we classify them as morbidly obese, yet there was nothing morbid about them; they had humongous heft, and enormous power. They are usually recruited from Japanese villages by scouts who scour the countryside in search of extremely fit, strapping young farm boys. They bring them to the Big City, subject them to a grueling regimen of physical training that would put the Marines boot camp to shame, and basically force-feed them. The rationale is simple: winning in the arena depends on momentum, and in high school physics we learned that momentum= mass x speed. So they build up their mass, and they train them for speed, agility, and overall fitness.
Once they retire from the sport these gladiators don’t sink into a morass of depression, alcoholism, overeating, and disease. Most of them are kept on as ushers, ticket takers, etc.; and they keep in shape. I saw some of them, and I wouldn’t advise Schwarzenegger to tangle with any of them. I inquired about their health status after retirement, and to my surprise they were pronounced hale and fit into their 70s and 80s. I did not have an explanation. Received wisdom dictated that these people are sitting ducks for diabetes and heart disease.

The answer, finally

I have to admit that every time I preached the benefits of weight control and the penalty sinners would inevitably have to pay, I had this nagging doubt: what about those sumo wrestlers?
In a recent JAMA article scientists from the University of South Carolina in Columbia looked into the issue of adipocity (fatness) vs. cardiorespiratory fitness as determinants of death. In a 12-year study, researchers found that among 2603 American adults over 60 years old, those who engaged in cardiovascular activity were living longer than those who exercised less, even when they had the same amount of body fat. Previous studies have shown that both the level of cardiovascular fitness and the amount of body fat played a role in the health of older Americans. But this study shows that cardiorespiratory fitness helps adults over 60 live longer, regardless of body fat.
The authors conclude: In this study population, fitness was a significant mortality predictor in older adults, independent of overall or abdominal adiposity. Clinicians should consider the importance of preserving functional capacity by recommending regular physical activity for older individuals, normal-weight and overweight alike.
So there, finally: the puzzle of the healthy sumo wrestlers solved. But more importantly for us soft and overweight weaklings: exercise, exercise! It is literally a question of life and death.
Dov Michaeli MD, Ph.D is in the biotech industry

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