Many of us would like to be in better shape, but feel like we don't have time to work out. Fortunately, recent research shows that high-intensity interval training (HIT) may offer significant benefits in much less time. HIT-workouts are completed in bursts of just a few minutes of intense exercise with short recovery breaks in between. This is good news for those on a tight schedule.

The Research: HIT Works!

Two studies published February 1, 2013, in the Journal of Physiology report that HIT may help you achieve the same results as longer exercise sessions in less than one-third of the time.

These studies, conducted by researchers at the University of Birmingham and John Moore Liverpool University, compared a type of HIT called Sprint Interval Training (SIT) with regular endurance training. Participants were divided into two groups. The SIT group completed three half-hour exercise sessions per week, in which they alternated hard 30-second sprints with cycling at a relaxed pace for four and a half minutes. The endurance-training group completed 40 to 60-minute cycling sessions.

Researchers found that even though the SIT participants exercised for less time, they achieved the same physical improvements as the endurance-training group. All study participants had improved muscle density and improved insulin-sensitivity, which may decrease the risk of type two diabetes. Participants also showed signs of improved health in their arteries, which may decrease the risk of heart disease. But, from a time-management perspective, the SIT participants came out on top. They achieved all these benefits in only 90 minutes per week.

Can You Do It?

If you're worried about being able to perform such intense workouts, there's hope. A 2010 study of HIT from scientists at McMaster University in Canada, also published in the Journal of Physiology, has shown that the intensity level need not be "all out" to be effective. First reported by Science Daily, the researchers found that participants only needed to exercise at about 95 percent of their maximum heart rate to get the benefits. That's still a good sprint, but much less difficult than sprinting as hard as you can.

HIT-expert Dr. Martin Gibala, one of the McMaster researchers interviewed by Science Daily, noted that doing 10 one-minute sprints on a stationary bike with one minute of rest in between, three times a week, may be as effective as many hours of biking more gently.

Added Benefits

If you're still not convinced, consider another study published in the American Journal of Human Biology, and reported by Science Daily. Researchers from the University of the West of Scotland found that brief, intense workout sessions might help prevent heart disease better than longer workouts.

The study examined the effects of HIT versus moderate exercise over seven weeks. The HIT participants performed a series of quick sprints for 30 seconds. The moderate group ran for 20 minutes straight.

Both groups improved their risk factors for heart disease. But the amount of time spent exercising by the end of the study period was six times higher for the moderate group. Researchers concluded that interval training is an effective and timesaving form of exercise that may help prevent heart disease.

HealthAhead Hint: Set Your Goal

Use the findings from these studies to set your own fitness goals, and save time, too! Remember, HIT can be intense. You may want to speak to your doctor first, especially if you have a medical condition that might interfere with your ability to exercise. When you're ready, try this HIT workout, which is similar to the one used in the research conducted at McMaster University:

Get started by scheduling time to exercise three times a week. On a stationary bike, practice 10 one-minute sprints. Take one minute of rest between each sprint. You should keep pedaling at an easy pace during the rest intervals. During your sprint intervals, you don't need to pedal as hard as you can--but you should put in a strong effort. This invigorating quick 20-minute workout may give a boost to your heart, muscles, and mind.