Fitness more important than fatness

I saw a talk at the SMA conference last weekend, and this bit blew my mind more than anything else: your cardiovascular fitness (VO2max) is more important to your health than how much fat you have. In fact, when you factor in cardiovascular fitness into overall death risk (and this is having all the other standard measures like smoking, drinking, weight, fat, hypertension, etc) everything else besides hypertension becomes completely negligible. Hypertension only stood up in the model because it's inversely and linearly related to cardiovascular fitness.

Recently, there's been a ton of focus and blame on obesity being the great evil (behind genetics). Now, don't get this research wrong--obesity can still really mess you over. But having a high VO2max was so much more important, that it almost didn't matter how obese someone was. Another caveat: having a high VO2max while being obese is very hard, but it does happen.

So some numbers to help bring the magnitude of this to focus:

• a normal weight, low fit person is 2.5x more likely to die than a normal weight, high fit person
• an obese, low fit person is > 3x more likely to die than an obese high fit person
• a normal weight fit person has the same death risk as an obese fit person
• an obese fit person has a lesser chance of dying than a normal weight unfit person

Now, like I said, it's hard to be both obese and fit, but it's certainly not too hard to be pretty darn fit and still a bit overweight.

Take home message: you need to push yourself on your cardio as hard as possible, and don't worry so much about if it's making you lose weight: worry about if you can push harder and longer each week.

Lastly, if you're interested in having your mind blown by more numbers, graphs, and jargon, the sources for this talk were mostly these 3:

Lee et al, 2010, Mortality trends in the general population: the importance of cardiorespiratory fitness, Journal of Psychopharmacology, 24(11) supplement 4, 27-35

Kodama et al, 2009, Cardiorespiratory fitness as a quantitative predictor of all cause mortality and cardiovascular events in healthy men and women, JAMA: The Journal of the American Medical Association, 301(19), 2024-2035.

McAuley et al., 2010, Obesity paradox and cardiorespiratory fitness in 12,417 male veterans aged 40 to 70 years, Mayo Clin Proc, 95(2) 115-121.