New evidence indicates that more frequent and more vigorous activity can turn back the biological clock.
Fifteen minutes of vigorous exercise or 30 minutes of moderate activity several times a week can reduce your risk of cardiovascular disease, obesity, diabetes, cancer, depression, and dementia. But according to recent studies, exercising even more vigorously for longer periods may have additional benefits by taking years off your biological age. It does so by increasing aerobic capacity—the amount of oxygen you can take in and distribute to your tissues in a minute. “Some studies have indicated that people in their 80s who exercised at high intensity for 20 to 45 minutes a day have an aerobic capacity of people 30 years younger,” says Dr. J. Andrew Taylor, director of the cardiovascular research laboratory at Harvard-affiliated Spaulding Rehabilitation Network.
How fitness is measured
Aerobic capacity is determined by measuring a person’s maximal oxygen consumption, or VO2max. Most of us don’t know our VO2max because measuring it requires running on a treadmill in a medical facility while hooked up to monitoring equipment. Because treadmill tests are expensive, they usually aren’t given to people who don’t have symptoms of heart disease.
A few years ago, Norwegian researchers asked 5,000 people to fill out a lifestyle and health-data questionnaire and take a treadmill test. When they compared the VO2max scores derived from the questionnaires to those from the treadmill tests, they found that the results obtained from the questionnaires closely approximated the treadmill results for about 60% of people. The questionnaire tended to underestimate VO2max slightly in the fittest people and to overestimate it in the least fit.
Since the questionnaire was developed, several groups of researchers have used it to see how VO2max relates to health. In an analysis of data from 55,000 people enrolled in an ongoing Norwegian health study, re-searchers found that women ages 60 or younger whose VO2max was at least 15% below the average for their age group had a 22% greater chance of dying prematurely than those with normal or high VO2max values.
Increasing aerobic capacity
We lose 10% of our aerobic capacity every decade after age 30, but vigorous exercise can reduce that loss. “How much of your VO2max you preserve depends on three factors—the intensity, duration, and frequency of your workouts,” Dr. Taylor says.
Exercise intensity increases as you come closer to achieving your maximum heart rate, which you can calculate by subtracting your age from 220. If you’re just beginning to exercise, try to get your pulse up to a rate of 50% of maximum. If you’ve been exercising a while, work up to 70%. Try to exercise at that level for 20 to 40 minutes, three to five days a week.
Find your biological age
The Norwegian researchers used the data from their studies to create a calculator to estimate a person’s biological age. It’s at www.worldfitnesslevel.org. If you find that you are biologically older than your years, that knowledge may serve as an incentive to become more active.