Dutch researchers found that exercising for an hour every two days lowered blood sugar as much as daily 30-minute workouts in a group of 30 men with type 2 diabetes.

Exercise is considered a cornerstone of diabetes treatment and just a single bout of physical activity is known to have profound effects on blood sugar levels.

But the number of times a week to exercise for the best results is unclear.

"Our findings suggest that frequent short bouts of moderate exercise can be substituted for less frequent exercise bouts of a longer duration in people with type 2 diabetes, or vice versa," Luc J.C. van Loon of the University of Maastricht in the Netherlands told Reuters Health by email.

Nearly 25 million Americans are estimated to have type 2 diabetes, often a result of excess weight and physical inactivity, according to the Centers for Disease Control and Prevention.

In type 2 diabetes, the body no longer responds appropriately to insulin, a hormone that helps ferry sugar from the blood into the cells, where it's used as fuel. That means diabetics often have higher blood sugar levels, especially after meals, which can damage organs and blood vessels over time.

The men in the new study were 60 years old on average and about half of them required insulin injections to control their blood sugar. The rest managed their condition with diet and sometimes pills for diabetes.

They all participated in three experiments that lasted three days each. Throughout, the men ate a standardized diet and were asked to stick to their daily level of activity.

In one of the three experiments, they cycled for 60 minutes on the first day and then rested the next day. In the other, they cycled for 30 minutes on two consecutive days, and in the third, they didn't exercise at all.

The researchers continuously monitored the men's blood sugar during exercise and for the next couple of days.

When the men didn't exercise at all, they had high blood sugar 32 percent of the time. But when they biked, their blood sugar was in the high range only 24 percent of the time, no matter which schedule they followed.

The two exercise schedules also did equally well in terms of lowering the men's average blood sugar levels.

According to van Loon, whose findings appear in the journal Diabetes Care, women with type 2 diabetes are likely to reap the same benefits as the men in this study.

However, the participants in the current study were relatively healthy -- they didn't have heart disease and weren't extremely obese, for instance. So it's not clear whether the results apply to all people with type 2 diabetes, because many may have health problems that make them unable to exercise as often or as much as the participants in the new study.

Currently, the American Diabetes Association recommends 150 minutes per week of moderate exercise, such as brisk walking.

"These findings set the stage for a more personalized exercise prescription, tailored to the needs and capabilities of the individual with type 2 diabetes," van Loon said.

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