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There is some good news for those who don't like spending hours in the gym. New research studies have found that short bouts of exercise have some significant health benefits.
In the first study, Scottish researchers discovered that regular high-intensity, three-minute workouts have a significant effect on the body's ability to process sugars. While a US study revealed that short bouts of weight training spread across the day may be just as effective at building children's bone mass as uninterrupted exercise sessions.
Research for the first study, published in the open access journal BMC Endocrine Disorders shows that a brief but intense exercise session every couple of days may be the best way to cut the risk of diabetes.
Professor James Timmons worked with a team of researchers from Heriot-Watt University Edinburgh, Scotland, to investigate the effect of 'high-intensity interval training' (HIT) on the metabolic prowess of 16 sedentary male volunteers.
He said, "The risk of developing cardiovascular disease and type 2 diabetes is substantially reduced through regular physical activity. Unfortunately, many people feel they simply don't have the time to follow current exercise guidelines. What we have found is that doing a few intense muscle exercises, each lasting only about 30 seconds, dramatically improves your metabolism in just two weeks."
Current exercise guidelines suggest that people should perform moderate to vigorous aerobic and resistance exercise for several hours per week.
Guidelines good, but only if you stick to them
While these guidelines are very worthwhile in principle, Timmons suggests that a lack of compliance indicates the need for an alternative, "Current guidelines, with regards to designing exercise regimes to yield the best health outcomes, may not be optimal and certainly require further discussion.
"The low volume, high intensity training utilized in our study substantially improved both insulin action and glucose clearance in otherwise sedentary young males, and this indicates that we do not yet fully appreciate the traditional connection between exercise and diabetes."
The subjects in this trial used exercise bikes to perform a quick sprint at their highest possible intensity. In principle, however, any highly vigorous activity carried out a few days per week should achieve the same protective metabolic improvements.
Timmons added, "This novel approach may help people to lead a healthier life, improve the future health of the population and save the health service millions of pounds simply by making it easier for people to find the time to exercise".
Building the bones In the second study, published in the International Journal of Sports Medicine, researchers investigated the impact of short bouts of weight training on bone mass building. Weight-bearing exercises, including weightlifting and high-impact activities like jumping, are known to help build and maintain bone mass. But it's not clear whether different training regimens - single, long workouts versus more-frequent, shorter ones, for example -have different effects on the bones.
Over six weeks, they put two groups of rats through an exercise regimen that mimicked human strength training, having the animals climb ladders with weights attached to their tails. One group did this once daily, three days a week; the other rodents worked out three days per week, but the session was broken down into three shorter bouts spread across the day.
A third group of rats served as a non-exercising control group.
No difference between long and short intervals
At the end of the study, both exercise groups showed gains in bone density compared with the control group, according to the researchers, led by Dr Ken D. Sumida of Chapman University in Orange, California, US.
There were no clear differences between the two exercise groups' bone mass gains.
If the findings do translate to children and teenagers, the researchers suggest that short bouts of exercise may be just as effective as longer - and more difficult - exercise sessions, Sumida told Reuters Health.
Other benefits
That could be important, he explained, because shorter, less-strenuous workouts would likely reduce the risk of injury, help prevent muscle soreness and be easier for kids to stick with.
Extrapolating the findings to children requires a lot of assumptions, Sumida noted. Even less clear is whether the results could be relevant to adults. Unlike in human adults, the growth plates at the ends of the bones in adult rats do not close, Sumida explained. This means that adult rats just keep getting bigger, and may not be a good model for what could happen in human adults' bones. - (EurekAlert/Reuters Health, Amy Norton)
SOURCE: International Journal of Sports Medicine, December 2008.
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