Q: What is high-intensity training (HIT)? Is it true that doing it for 10 minutes is as good as a standard hour-long cardio workout?
A: It’s a short, intense version of interval training that’s being promoted as a way to provide the most benefits in the least time.
With regular interval training, you alternate short bouts of intense and moderate exertion, such as running, cycling, swimming or stair climbing. For example, you might cycle very hard for two to four minutes, then pedal for two to four minutes at a more relaxed pace, then speed up again, and so on.
With HIT, the bouts of exertion are even shorter and more intense (usually 90 percent of maximum exertion), and you stop (or at least slow down greatly) in between. For example, after warming up, you can do 10 one-minute, all-out sprints on a stationary bike with one-minute rests in between.
Some small, short-term studies from McMaster University in Canada have found that HIT workouts, done three times a week, can be as good—in terms of exercise capacity, blood sugar control and other metabolic improvements—as longer cardio regimens. However, HIT won’t burn as many calories as longer, moderate-intensity workouts.
Most of the research has been done with fit young people. But some studies have found that HIT or other forms of interval training can be safe and beneficial for older people—even those with chronic diseases.
Still, HIT can greatly increase stress on your heart and muscles. As with any new vigorous exercise program, consult your doctor before starting this if you have been sedentary or have a medical condition or previous injury that limits your ability to exercise.
If you want to get a taste of HIT, get on a stationary bicycle and, after first warming up, pedal as fast as you can for 20 seconds. Then, cut back to very gentle pedaling for a minute, followed by another all-out 20-second sprint. Repeat as you can. Do this for a few minutes several times a week. Try to work up to one- or two-minute sprints, repeated 10 times.