The thought of going for a long run makes you hate life. So what would motivate you to exercise?

A fun workout -- mimicking a boxing bout or sprinting on a bicycle -- could actually be better for you, it turns out.

With interval training, which alternates bursts of high-intensity exercise with periods of rest or easier effort, you can do more in less time, experts say.

Interval workouts have long been a training mainstay for athletes, but the method has gained a wider following as studies show that interval training can achieve a variety of results -- losing weight, ramping up stamina, increasing adaptability to different activities -- faster than traditional workouts.

In kickboxing classes, participants often punch heavy bags for three minutes -- the length of one round in a boxing match -- then rest for 30 seconds or more. Exercisers can make their own interval routines by alternating periods of harder and easier exercise when running or using cardio machines.

The technique packs a lot of punch because the overall amount of intensity is greater and the body works harder to switch gears between intervals, said Cedric Bryant, chief science officer for the American Council on Exercise, a nonprofit fitness organization.

For example, Bryant said, if you are running steadily for half an hour, you may be able to keep up a 10-minute-mile pace. But if you alternate intervals for half an hour -- running some stretches at a seven-minute pace and others at an 11-minute pace -- overall you'll work harder and run farther, he said.

David Cloud, a recreation program supervisor for the Parks and Recreation Department in Hillsboro, Ore., supervises boxing classes that he says are popular because they work. Not only that: "It's fun. Time goes by fast."

A study published in the January Journal of Physiology compared a group that did sessions of interval cycling with a group that did continuous cycling.

Participants in both groups achieved similar fitness results, but the interval group took only 1 1/2 hours each week to do so, compared with 4 1/2 hours each week for the other group, researchers said.

Researchers caution that these studies examined particularly intense workouts, with 30-second intervals of all-out maximum-intensity effort in healthy young adults.

In the real world, interval times and intensity will vary, depending on a person's fitness level and workout goals. High-intensity periods can be 30 seconds to three minutes, and rest periods can go from 30 seconds to four minutes.

Bryant, of the American Council on Exercise, recommended that people gradually increase the length and intensity of intervals and use interval training every other day for, perhaps, up to an hour.

In general, during the high-intensity periods, you should be out of breath and it should be difficult to converse, Bryant said. During rest periods, you should be able to breathe easily and speak comfortably, he said.