- In a study out of Brazil, researchers discovered that 20-minute interval sessions can help increase fitness levels, decrease body fat, and increase lean muscle mass in postmenopausal women.
- The magnitude in muscle gain was similar to what you would see in a strength-training program, according to the researchers.
- Steady-state exercise has not been shown to give the same effects.
Thanks to plummeting estrogen production, menopause is usually accompanied by a trio of not-so-great changes: a decrease in lean muscle mass, an increase in body fat, particularly around the abdomen, and a reduction in aerobic fitness activities.
As a result, postmenopausal women carrying extra weight are at higher risk for developing insulin resistance—a condition where your cells can’t absorb sugar in the blood as readily, leading to higher blood sugar levels and raising your risk of diabetes—and cardiovascular disease.
But the good news is that these shifts don’t need to be inevitable: Even a seemingly modest amount of interval training Florida Mom Runs 5:11 Mile While Pushing Stroller study published in the journal Menopause.
Previous research has demonstrated the value of sprint interval training for fat loss and muscle gain in younger men and women. So researchers from Australia wanted to see whether the same held true for older women, too.
They recruited 40 postmenopausal women and separated them into an exercise group and a sedentary group. The activity group participated in an eight-week program of sprints, doing 20 minutes on an exercise bike—comprised of 8-second sprints and 12-second low-intensity pedaling time—three a times a week. That’s just eight hours of exercise in total.
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At the end of the program, women in this group put on 1.5 pounds of muscle in their legs and trunk, lost 0.8 pounds of body fat, and increased aerobic fitness by 12 percent. There was no change in the sedentary group.
The increase in muscle mass compares favorably to weight training effects, lead researcher Yati Boutcher, Ph.D., of the University of New South Wales in Australia, told Bicycling. But the sprints offer a quicker increase in muscle mass in the trunk and legs compared to resistance training, which would take more time for achieving similar effects.
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In terms of mechanism, that’s unclear, she added. But it probably involves a large increase in mitochondrial and myofibrillar protein synthesis in the legs, thanks to sprinting on the bike, and increase in protein synthesis in the trunk because of the constant isometric contraction—and both aid in muscle growth.
If you’re not a fan of sprinting, can you get the same results by increasing the distance on your next run? Probably not, Boutcher said.
“Interval sprinting has been consistently shown to result in far more clinical benefits compared to aerobic exercise [like steady-state running] or leisurely walks in far less time,” she said.
