Researchers show that exercisers can burn as many as 200 calories in only 2.5 minutes by incorporating sprint interval training, dramatically cutting the time needed for a work-out.

In this new study conducted by a team from the University of Colorado Anschultz Medical Campus and Colorado State University, researchers compared volunteers' energy disbursement on two separate days, one on which they completed a sprint interval workout on a stationary bicycle. Conclusions showed a slight increase in the amount of calories that were burned on workout day, regardless of the short amount of time spent doing authentic strenuous exercise.

A large chunk of time spent in an effort to work out, is an annoying turn-off for many people that want to be in better shape. This new finding could make exercise reasonable for potential fitness buffs by squeezing intense efforts into a smaller time slot. A previous study had hinted at a similar program but using High Intensity Training at 3 minute intervals, which was also successful.

The team's research will be presented at The Integrative Biology of Exercise VI meeting being held October 10-13 at the Westin Westminster Hotel in Westminster, CO.

The study's leader, Kyle Sevits, points out that few Americans reach the U.S. government's recommendation of 150 minutes of moderate exercise or 75 minutes of aggressive exercise a week.

Sevits explains:

"Research shows that many people start an exercise program but just can't keep it up. The biggest factor people quote is that they don't have the time to fit in exercise. We hope if exercise can be fit into a smaller period of time, then they may give exercise a go and stick with it."

Despite previous research pointing out that sprint interval training can significantly improve fitness and athletic performance, little information was available about exactly how this type of exercise affects energy output, a detail that motivates many people to exercise.

Feeling the Burn

To measure how many calories a typical sprint interval training workout would burn, Sevits and his team performed a study using five healthy male volunteers between the ages of 25 and 31 years old. The volunteers first completed a stress test to ensure their hearts were healthy, follow by analysis of their body composition and resting metabolic rates.

For three days, the participants ate a specific diet to meet their metabolic needs, putting them in a state of energy balance. After three days, the men were taken to a hospital room that was completely enclosed where researchers controlled air intake, exhaust, and used equipment to measure water, oxygen, and carbon dioxide contents. Using these analysis, the investigators were able to determine how many calories the volunteers burned while in this room.

For two days, each man lived in the room, continued with their strict diet and participated in only inactive events such as watching movies, or using a computer. Additionally, on one of those days, they performed a stationary bicycle sprint interval workout, pedaling as fast as possible while the bike was set at a high resistance for five 30-second periods, with 4 minute recovery periods in between during which they pedaled slowly with little resistance. The researchers coached the volunteers over an intercom system, pushing them to give 100 percent.

Motivation is Key

Results analysis revealed that the volunteers burned an average of an extra 200 calories on the sprint interval workout day, in spite of only strenuously working out for 2.5 minutes. Although the investigators cannot yet theorize if this effort can translate into weight loss, Sevits and his team believe that participating in powerful, but brief bouts of exercise, could help in keeping a healthy weight.

Sevits concludes:

"Burning an extra 200 calories from these exercises a couple of times a week can help keep away that pound or two that many Americans gain each year."

A potential issue could be maintaining the highest effort needed to exercise at top intensity, during the 30-second sprints without help. To aid with motivation, Sevits recommends the use of a personal trainer.

Written by Kelly Fitzgerald