A few quick, intense bursts of energy, such as 7.5 minutes per week of sprints on a stationary bicycle, may be just as good as 30 minutes per day of moderate exercise in reducing the risk of type 2 diabetes. In fact, say researchers at Heriot-Watt University in Edinburgh, Scotland, such short bursts may be even more effective.
The research team, led by Dr. James A. Timmons, studied the effects of intense short-term exercise on the ability of sedentary young men to metabolize glucose. They found that just 15 minutes of all-out bicycling, spread over a 14-day period, not only increased insulin sensitivity, which is a common benefit of 30-minute-daily exercise programs, but also actually lowered BG levels. The latter result is significant because traditional exercise programs have not been shown to directly reduced blood glucose levels.
Participants in the study included 16 men in their early twenties who performed four to six all-out bicycle sprints lasting 30 seconds each, with four minutes of rest in between. The exercise sessions were short, taking from 17 to 26 minutes. Because the aim of the study was to see how quickly blood sugar and blood insulin levels would return to normal due to intense exercise, the researchers gave the men a high-glucose solution (75 grams) before each session.
After two weeks, they found that the time it took the men’s blood sugar level to return to normal was reduced by 12 percent, while their blood insulin level recovery time was reduced by 37 percent. The ability of the body to regain normal levels quickly means less exposure to high blood sugar, which over time can inflame vital organs and bring on diabetes and cardiovascular disease.
The Edinburgh study, which was reported in the journal BMC Endocrine Disorders, used too small a sample to permit broad conclusions about how people with or at risk for diabetes should change their exercise habits. Timmons did say, however, that his team’s study points out a potentially fruitful line of diabetes prevention and opens the door to sampling the effects of intense exercise in a far larger number of participants. In any case, because the study was conducted among younger men in relatively good health, he cautioned people over the age of forty to take on intense workouts gradually and under medical supervision.