Short, intense exercise produces health benefits

Busy workers with little time for exercise may be heartened by a recent small Scottish study that concluded that short bursts of intense exercise every few days could dramatically reduce the risk of certain diseases.

"Many people feel they simply don't have the time to follow current guidelines on exercise," says Dr. James Timmons, one of the study's researchers.

These guidelines recommend that we perform moderate to vigorous aerobic and resistance (isometric) exercise several hours a week.

"The risk of cardiovascular disease or Type 2 diabetes is greatly reduced by regular physical activity," says Timmons, "but we also found that short bursts of exercise can be highly beneficial."

• The researchers studied 25 inactive men, each of whom did four to six 30-second sessions on an exercise bike, going as fast as they could and taking four minutes of rest between each sprint.
• They did this three times a week for two weeks.
• The result — based on a total of just 15 minutes of intensive exercise over the course of a fortnight — was a 23 per cent improvement in insulin sensitivity, demonstrated by the speed at which the subjects' bodies removed glucose from the bloodstream after exercise.
• The explanation for this is that intense muscle contraction is the only way to remove glycogen — the body's stored form of glucose — from muscles.

• "Think about diabetes as being glucose circulating in the blood rather than stored in the muscles where it should be," says Dr. Timmons. "If we take out the glycogen from the muscles through exercise, then the muscles draw in that excess glucose from the blood."
• He recommends four all-out 30-second sprints on an exercise bike three times a week.
• You could get similar benefits, he says, by running up and down four flights of stairs three times, twice a week.
• This exercise routine, known as "high-intensity interval training," or HIT, can work for men and women of all ages.