LONDON (Reuters) - Rigorous workouts lasting as little as three minutes may help prevent diabetes by helping control blood sugar, British researchers said on Wednesday.

The findings published in the journal BioMed Central Endocrine Disorders suggest that people unable to meet government guidelines calling for moderate to vigorous exercise several hours per week can still benefit from exercise.

"This is such a brief amount of exercise you can do it without breaking a sweat," said James Timmons, an exercise biologist at Heriot-Watt University in Edinburgh, who led the study.

"You can make just as big as an effect doing this as you can by doing hours and hours of endurance training each week."

Type 2 diabetes, which affects an estimated 246 million adults worldwide and accounts for six percent of all global deaths, is a condition in which the body gradually loses the ability to use insulin properly to convert food to energy.

Very strict diet and vigorous, regular and sustained exercise can reverse type 2 diabetes, but this can be difficult for many people. The condition is closely linked to inactivity.

Timmons and his team showed that just seven minutes of exercise each week helped a group of 16 men in their early twenties control their insulin.

The volunteers, who were relatively out of shape but otherwise healthy, rode an exercise bike four times daily in 30 second spurts two days a week.

After two weeks, the young men had a 23 percent improvement in how effectively their body used insulin to clear glucose, or blood sugar, from the blood stream, Timmons said.

The effect appears to last up to 10 days after the last round of exercise, he added in a telephone interview.

"The simple idea is if you are doing tense muscle contractions during sprints or exercise on a bike you really enhance insulin's ability to clear glucose out of the bloodstream," Timmons said.

The findings highlight a way for people who do not have time to work out a few hours each week as recommended to improve their health, he added.

His team did not look for other important benefits to health that come from exercise, such as lowered blood pressure or weight control, but said another study had shown similar benefits to heart function.

But Timmons said getting people to exercise even a little could translate into big savings for health systems that spend hundreds of million of dollars treating diabetes.