How to Lengthen Your Telomeres with Exercise—And Why You'll Want To

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At the outer tips of each chromosome in every cell of your body lie the protein caps called telomeres, which protect your genes from damage. You'll want to make it your exercise mission to keep these telomeres long and strong. After all, healthier DNA means a healthier you.

And the good news is that you can not only maintain your telomeres' vibrancy but even rebuild (a.k.a. lengthen) them after being worn down (by stress, lack of sleep, and such)—and actually give them periodic checkups. (Related: How to Hack Your Telomeres to Slow Aging and Live Longer)

Cardio Is Queen for Lengthening Your Telomeres

Ever since exercise was found to build up telomeres—by stimulating the body's production of the enzyme telomerase—the question has been about the most effective workout route. A new study from the University Clinic of the Saarland in Germany found that a single 45-minute jog spiked telomerase activity in exercisers for several hours after, while a traditional weight-machine circuit had little to no effect. After working out three times per week for six months, the joggers—as well as a HIIT group (alternating four-minute hard runs with equal jogs)—saw a 3 to 4 percent increase in telomere length; the weights group saw no change.

Because the higher overall heart rate when doing endurance and interval exercise stimulates the cells that line the inside of our blood vessels, this causes an increase in telomerase (and nitric oxide synthase), says lead study author Christian Werner, M.D. "So it's basically like you're making a deposit into an antiaging account each time," he says.

Still, you don't want to drop the weights, says exercise scientist Michele Olson, Ph.D., a Shape Brain Trust pro: "Resistance training is the key to maintaining muscle and bone as we age." (More Info: The Best Anti-Aging Workout You Can Do)

How to Track Your Telomere Fitness

The proliferation of genetic-testing services means the average exerciser can find out how fit their telomeres are. At gyms like NY Strong in Mamaroneck, New York, members can have their telomeres tested, then get a personalized exercise plan. And the TeloYears at-home DNA kit ($89, teloyears.com) uses a finger-stick blood test to determine your cellular age based on telomere length.

"I recommend getting your telomeres tested every five to 10 years to see how you're aging," says Michael Manavian of Greenwich DX Sports Labs, which runs the testing at NY Strong.

And in the meantime, follow the lead of trainer Jillian Michaels, whose new book,

The 6 Keys

, reveals science-backed strategies for helping your body age better: "I always include HIIT training in my regimen—as well as yoga, which has been shown to lower stress and thereby also help preserve telomeres."