The Science of Running
By Alex Hutchinson VO2 Max: The New Vital Sign; Ankle Power; Brain Boosting; Save the Knees
Everyone knows that fitness and health are closely linked. But a recent scientific statement from the American Heart Association takes this a step further, proposing that the most common marker of aerobic endurance should be considered a “vital sign” and measured regularly by your doctor. Cardiorespiratory fitness, often referred to by its scientific abbreviation, VO2max, is a measure of how much oxygen your muscles are able to use when you’re pushing all-out. It’s a good (though not perfect) predictor of how fast you’ll run in a race – and more importantly, the new aha statement points out, it’s a powerful predictor of your risk of a wide range of serious conditions like heart disease, certain types of cancer, Alzheimer’s and depression. A low VO2max is a bigger risk factor than smoking or high blood pressure, in some cases.
So how do you measure VO2max? The ideal test involves running to exhaustion on a treadmill while hooked up to sophisticated oxygen-measuring equipment – not exactly easy to add to your medical checkup. But there are other ways of estimating VO2max that are “no more difficult than measuring blood pressure,” says Queen’s University researcher Robert Ross, one of the authors of the aha statement. The simplest is an equation based on your resting heart rate, waist circumference, age and responses to a three-question survey of your exercise habits. Other options include assessing your heart rate during a one-mile walk, and seeing how far you can run during an all-out 12-minute run.
For runners, of course, there’s an obvious alternative: racing. While your race times aren’t a direct measure of VO2max, they offer a pretty decent estimate, as well as a simple way of tracking progress. Online tools like the one at runsmartproject.com/calculator allow you to enter a recent race performance and give you an estimate of “vdot” (the term used by coach and researcher Jack Daniels for his VO2max estimates). The biggest health risks are seen in people with VO2max values below about 18 ml/kg/min, with values above 35 being even better. But details aside, the important message to remember is that when you’re straining to notch a new personal best, you’re also improving one of your most important vital signs. Alex Hutchinson is a contributing editor and one of the most respected sports science writers in the world.