Just Do It (Do or Die!)

Many of us who go to the gym and run on a treadmill ignore the electronic readouts that tell us how many MET units we achieve during our workouts. New research published in the August 4 issue of the New England Journal of Medicine reveals that we should be paying much closer attention to those numbers.

Dr. Martha Gulati, et al., studied the results of 5,721 exercise stress tests performed on women aged 35 and older. All of the tests used the Bruce Treadmill Protocol.

Those researchers found that women who score less than 85 percent of their age-predicted exercise capacity during an exercise stress test were twice as likely to die within 8 years as those who score 85% or higher.

They determine fitness level using units of metabolic equivalents (MET). One MET is the the amount of oxygen used when sitting quietly for one minute. Moderate walking burns 3 - 6 METs per minute, while running can consume more than 6 METs/minute. A 50-year-old woman performing vigorous exercise should be able to reach 8.2 METs, while the predicted exercise capacity for a man of the same age comes out to 9.2 METs.

The study finds that women lose about 1% of their exercise capacity per year, so the researchers devised a simple table, which they call a nomogram, that helps women find their prescribed exercise level. The next time you are on that treadmill, pay attention to the METs. Then draw a straight line on the table between your age and the METs your burned. The point where that line intersects with the table's slope shows your percentage of predicted exercise capacity for age. If that percentage falls below 85%, you better ramp it up the next time!