You already know working out regularly can help keep you slim, boost your mood, aid your sleep, and even stave off disease. But a new study has identified a potential mode of exercise that may help optimize the reversal of any unwanted signs of aging — high-intensity interval training (HIIT).
The idea is that instead of long, steady movement (think: running several miles on a treadmill at the same speed and incline), alternating between quick spurts of intense, all-out exercise and lower-intensity exercise during HIIT can help raise your heart rate and enable you to shed more fat, faster.
In the new study, published Tuesday in Cell Metabolism, researchers found HIIT in aerobic exercises like biking and walking revved cells’ ability to generate more proteins within mitochondria and their protein-building ribosomes — essentially stunting aging at a cellular level.
"Based on everything we know, there's no substitute for these exercise programs when it comes to delaying the aging process," senior study author Sreekumaran Nair, a medical doctor and diabetes researcher at the Mayo Clinic in Rochester, Minnesota, said in a news release. "These things we are seeing cannot be done by any medicine."
Researchers enrolled 36 men and 36 women from a younger group (ages 18 to 30) and an older group (ages 65 to 80). Each group received a different exercise assignment: either high-intensity interval biking, strength training with weights, or a regimen that combined strength training and HIIT.
Next, they biopsied participants’ thigh muscles and compared their molecular makeup against those of sedentary volunteers’. They also analyzed the participants’ lean muscle mass and insulin sensitivity, which is a marker for type 2 diabetes.
They found strength training aided muscle building, but the younger group that did HIIT saw a 49 percent increase in mitochondrial capacity and the older group saw a 69 percent increase. HIIT also helped reduce insulin sensitivity.
The one thing HIIT wasn’t good for? Building muscle. That’s why a mix of HIIT and strength training may offer the most benefits, as muscle mass tends to decline with aging, Nair noted.
"If people have to pick one exercise, I would recommend high-intensity interval training,” Nair said in the release, “but I think it would be more beneficial if they could do 3-4 days of interval training and then a couple days of strength training.”