NEW YORK -- Many people begin the new year with a vow to get back into shape, and the government says we need 75 minutes of vigorous exercise a week. One way to get in those minutes is through high intensity interval training (HIIT).
For those who get tired just thinking about strenuous exercise without rest, HIIT could be the perfect fitness approach.
HIIT involves short bursts of high intensity exertion, like a minute of running as fast as you can, followed by short recovery periods such as a slow jog.
The regimen varies from place to place. At Orange Theory Fitness in New York, the goal is to work out in what they call "the orange zone" at a high intensity level for twelve to twenty minutes of an hour-long class.
Thirty-six-year-old Shelly Ramsammy has asthma, and used to be afraid of vigorous exertion. "I felt completely out of shape."
But she tolerated the interval training well, and last summer, she had added incentive.
"I was just trying to get fit for a trip. I was like, 'Oh my gosh, I'm going to be in a bikini, I have to get fit.'"
After building up slowly, as exercise experts recommend, Ramsammy now runs twice as fast as before.
Research shows high intensity training stimulates the muscles to burn fat and sugar more effectively. Why is HIIT getting so much attention now?
"I think its because research has been showing that it can be pretty powerful in improving people's risk factors for heart disease and diabetes," said Carol Ewing Garber, who teaches the science of exercise at Columbia's Teacher's College.
It may be powerful, too, in getting some people off the couch. Because at the end of the day, exercise works best if you actually do it.