We’re all looking for a fitness routine that provides the most benefits with the least effort in the shortest time. That’s why pie-in-the-sky ads for special exercise equipment or programs that promise a week’s worth of training in, say, just 10 or 20 minutes tempt so many buyers.
There is no such magic regimen, but there is one way to get more out of your cardiovascular workouts—interval training. Coaches and trainers have used it for many years. Recent research has confirmed its benefits and brought it new attention.
Interval training involves alternating short bursts of intense and moderate exertion. It can be done with any kind of cardiovascular exercise, such as running, cycling, swimming, or stair climbing.
For example, you cycle very hard for two minutes, then pedal for two minutes at a more relaxed pace, then speed up again, and so on. Some exercise machines, such as elliptical trainers, are programmed for interval training.
Studies have found that interval training can improve endurance and fitness better than moderate-intensity workouts at a steady pace, and in less time. And it can help improve blood sugar control, lower blood pressure, and raise HDL (“good”) cholesterol.
Interval training helps improve the efficiency and endurance of muscles by making them alternate between aerobic exertion (in which oxygen is used to burn carbohydrates and fat for energy) and anaerobic exertion (without oxygen).
It may allow exercisers to maintain a higher overall intensity because they know that recovery periods are coming up. The recovery periods also allow for the removal of some lactic acid that accumulates in the muscles and makes them tire. Andinterval training can add variety to your workouts.
Not just for the young
Most of the research has been done with fit young people, but some recent studies have found that interval training can also be safe and beneficial for older people—even those with chronic diseases.
Norwegian studies, for instance, have shown that supervised interval training can improve cardiovascular health, the ability to exercise, and quality of life in people with heart failure more than low- to moderate-intensity exercise.
Another study compared interval and regular training in people who had coronary artery bypass surgery, and found that interval training provided greater benefits in endurance and in the ability to tolerate spurts of exertion.
Stepping it up
If you want to try interval training, start with two or three sessions a week. If you run, for instance, just speed up for one to four minutes, then slow down for a similar period, then keep alternating.
If this feels good, try increasing the length or intensity of the strenuous bouts. You can also vary the length of the slower bouts (which can be shorter or longer than the intense spurts), as well as the length or intensity of the overall workout. See what works best for you.
Ideally, the intense bouts should get your heart rate up to 85 to 90 percentof its maximum (you can compute your maximum heart rate by subtracting your age from 220 beats per minute). You need not “go all out” unless you’re an athlete or at least very fit. During the recovery periods, try not to let your heart rate drop below 60 percentof its maximum.
Keep in mind, if weight loss is one of your exercise goals, there’s no shortcut. Though interval training burns lots of calories in a short period, it takes longer, moderate-intensity workouts to produce and maintain weight loss
Important note: If done intensely, interval training can put markedly increased stress on your heart and muscles. As with any new vigorous exercise program, consult your doctor before starting interval training if you have been sedentary or if you have a medical condition or previous injury that restricts your ability to exercise.
In particular, if you have heart disease, high blood pressure, or arthritis, sudden intense bouts of exercise may not be advisable. You may also need the advice of a physical therapist.