Does fitness offset fatness?

These days, most adults are overweight, not active, or both. If you could change just one—become active or lose weight—which would be better?

At least for men, being more fit may have a bigger health payoff than losing weight, according to a new study of more than 14,000 well-off middle-aged men who are participating in the Aerobics Center Longitudinal Study. Researchers followed their health, weight, and exercise habits for 11 years. They estimated how physically fit the men were by calculating their metabolic equivalents (METs) from a treadmill test.

Compared with men whose fitness declined over the course of the study, those who maintained their fitness levels reduced their odds of dying from cardiovascular disease or any other cause by about 30%, even if they didn’t lose any excess weight. Those who improved their fitness levels saw a 40% reduction.

Body-mass index (BMI), a measurement that takes weight and height into account, was not associated with mortality. The results were published in the journal Circulation.

What is “fitness”

Fitness is a measure of how well your heart, blood vessels, blood, and lungs supply your muscles with oxygen during sustained exercise. It also takes into account the ability of your muscles to use that oxygen.

The most straightforward way to gauge fitness is to use a treadmill to measure peak exercise capacity. That means you run on a treadmill as its speed and incline are progressively increased until you can’t go any further. Exercise capacity is usually measured in METs. One MET is the amount of oxygen you use when sitting still or sleeping. The number of METs at peak exercise capacity is determined by a formula based on your speed and the incline at your peak.

Make a leap

Maintaining a healthy weight and being active are two of the best things you can do for your health. But what if you are overweight and inactive? This study and others suggest that getting more activity is the best place to start if you want to improve your health.

It doesn’t matter where you are starting from. If your fitness is low today, you can boost it with regular physical activity that challenges your body. That means working your body hard enough to speed up your heartbeat and breathing. If you need help getting started, a Special Health Report called Exercise: A program you can live with, from Harvard Medical School, can help.

If you don’t regularly work your heart, lungs, and muscles, then any increase in activity is great. Burning an extra 300 calories a week, the equivalent of raking leaves for an hour, can improve health. And with exercise, more is usually better.

If you already carry extra pounds despite ramping up your exercise, this study—and hundreds before it—suggest you still want to try to shed them. Getting down into a healthy weight range is good for long-term health.

Maintaining fitness and a healthy weight is the winning one-two punch.