(Corrects reference to hemoglobin A1c to 3 months from 6 in 11th paragraph)
By Maggie Fox, Health and Science Editor
WASHINGTON (Reuters) - Weight training works just as well as running on a treadmill or biking to help the most important symptom of type-2 diabetes -- long-term control of blood sugar -- Canadian researchers said on Monday.
Doing both aerobic and resistance training lowered blood sugar levels better than either alone, researchers said -- and both appeared to be safe.
At least 194 million people worldwide have diabetes, and the World Health Organization expects the number to rise to more than 300 million by 2025.
Most have type-2 diabetes, caused by a combination of genetic predisposition, lack of exercise and rich diet.
Exercise -- the type that makes people breathe a little heavily -- is known to reduce the risk of type-2 diabetes and can improve the body's control of sugar. But there were doubts about the safety and effectiveness of weight training.
Dr. Ronald Sigal of University of Calgary and colleagues at the University of Ottawa studied 251 people with type-2 diabetes aged 39 to 70. None exercised regularly.
They assigned them to one of four groups -- one that did 45 minutes of aerobic training three times a week, another doing the same amount of resistance training, a group that did both, for a total of an hour and a half of exercise three days a week, and a fourth group that did no extra exercise.
The exercisers used treadmills or exercise bikes, or weight machines, at a health club. The volunteers liked the exercise and stuck with it, Sigal said.
"I think there is a widespread cynicism even among medical people that people will actually exercise," Sigal said in a telephone interview.
They were given a diet to follow that should have prevented any weight loss, and then their blood sugar, cholesterol, weight and other vital statistics were measured.
Blood sugar levels fell with exercise and most importantly, hemoglobin A1c, which measures the blood sugar average for the past 3 months, fell by half a point on average in the people who did one form of exercise and a full point in those who did both.
A1c should be between 4 and 6 but the patients started out with A1c values ranging from 6.6 to 9.9, Sigal's team wrote in the Annals of Internal Medicine.
A one point drop in A1c is associated with a 15 percent to 20 percent decrease in major cardiovascular events such as heart attack or stroke and a 37 percent reduction in complications such as kidney, eyes and limb damage.
"There were some who brought their A1c into the normal range," Sigal said. Some also were able to lower their doses of medications and many lost weight and body fat.
"Imagine an inexpensive pill that could decrease the hemoglobin A1c value by 1 percentage point, reduce cardiovascular death by 25 percent, and substantially improve functional capacity (strength, endurance, and bone density)," Dr. William Kraus of Duke Medical School and Dr. Benjamin Levine of the University of Texas Southwestern Medical Center wrote in a commentary.
They said doctors should prescribe exercise to every diabetes patient.