Here's some miracle news for those who want to stay in shape and ward off disease, but also want to spend most of their time slouching and lounging around. A new study has found that very short but intense bursts of exercise prevent diabetes and cardiac problems more effectively than long, sweat-provoking workouts. In fact, the mini-exercise sessions that work so well are short enough that you could almost complete them during a commercial break.
In the journal BMC Endocrine Disorder, scientists report how they monitored blood sugar and cardiac function in 16 young male subjects who performed four 30-second sprints on an exercise bicycle every other day for two consecutive weeks. That comes to about 15 minutes of exercise over the two-week period, total. Apparently, the subjects pedaled as hard as they could for the 30-second duration, rested a few minutes, and then repeated three more times. And for that minimal effort, the volunteers reaped a 23 percent improvement in insulin function.
Study director James Timmons commented, "Doing a few intense muscle exercises, each lasting only about 30 seconds, dramatically improves your metabolism in just two weeks... Low-volume, high-intensity training ... substantially improved both insulin action and glucose clearance in otherwise sedentary young males." According to the report, the 15-second sprints provided more benefit than one hour of running a day.
The magic works because of the way the body utilizes glucose. Dr. Timmons explains that sugar metabolism goes haywire when excess glucose circulates in the blood rather than residing in the muscles, where it belongs. But when you exercise, your muscles start to use up their glycogen stores, and then they start drawing excess glucose from the blood. Short sprints draw on glycogen more aggressively than long bursts of exercise because, "If you go for a jog or a run you oxidize glycogen but you are not depleting the glycogen in your muscles," says Dr. Timmons. "The only way to get to this glycogen is through very intense contractions of the muscles [as through the all-out sprints]."
The benefits of exercise in reducing insulin resistance have long been known, but earlier studies focused on the impact of the traditional hour-long aerobic sessions totaling at least 2.5 hours a week. For instance, one Australian study in 2007 found that diabetic children who exercised for an hour three times a week but who didn't alter their diets nevertheless significantly improved their insulin resistance. Also in 2007, researchers reviewed 103 studies and found that aerobic exercise alone more effectively controlled diabetes than other lifestyle changes or combinations of approaches. And a simultaneous study found that while weight-training exercise helped control diabetes and aerobic exercise helped even more, a combination of the two forms of exercise for three 45-minute workouts weekly led to an additional 15% to 20% decrease in heart attack and stroke risk and a 25% to 40% lower risk of diabetes-related eye or kidney disease.
The bottom line, it seems, is that doing any exercise at all will help to prevent and control diabetes -- but hard, intense bursts of exercise help the most. The short-burst workouts are known as "high-intensity interval training," or HIT for short. While the results certainly seem promising for those with little time or desire to hit the gym, remember that only healthy males were tested, and they were tested only for glucose tolerance. While research continues, for your all-around health, it certainly couldn't hurt to continue doing your regular workouts but you might want to add some interval training, as well.
And do remember if you're at risk for diabetes that, as I've written before, forcing blood sugar levels down via medications does nothing to relieve the underlying diabetic condition. If you want to prevent and reverse diabetes, you have to reduce your high glycemic carbohydrate intake, reduce insulin resistance, improve beta cell function in the pancreas, and protect and repair insulin/sugar damage to mission critical organs in the body -- all at once. This means implementing dramatic lifestyle changes all at once -- including the exercise routines described here, controlling diet, and perhaps introducing a natural glucose metabolizing supplement.