Long-term, intensive exercise can greatly improve the body's ability to control blood sugar levels, helping to stall the development of diabetes or cardiovascular disease in at-risk patients, according to researchers at Duke University Medical Center.
The benefits of an exercise program are still at work one month after the exercise is discontinued and just one single session of exercise can immediately improve glucose metabolism, the researchers reported in the journal Clinical Exercise Physiology.
"It now appears that there is also a long-term beneficial effect from regular exercise, most likely due to the fact that a significant a mount of fat is lost," said Cris Slentz, PhD, exercise physiologist and author of the study. "Long-term exercise leads to loss of fat in the gut region, which is especially beneficial since this fat is thought to be directly linked to increased risk of diabetes and heart disease.'
Researchers put five overweight and sedentary people on a nine-month intensive exercise program consisting of four exercise sessions each week, beginning with 15 minutes each day and increasing to 60 to 70 minutes daily. The program included stationary bike riding, treadmill, walking and stair climbing. After nine months, the participants spent one month in a "de-training" program.
The participants' blood glucose and insulin levels were measured before the start of the training, and again one day, five days and 30 days afterward. The blood samples were taken after eight-hour fasts so the results would not be influenced by what the participants were eating.
"Insulin sensitivity, or its ability to stimulate glucose metabolism, was higher after nine months of exercise, and the fasting insulin levels were lower," said Slentz. "Just as importantly, 30 days after stopping exercise, insulin sensitivity was still 24 percent higher than pre-exercise levels, indicating that beneficial effects of exercise persisted."
"These results provide strong evidence that long-term exercise training can lead to both short- and long-term improvements in carbohydrate metabolism," said Dr. William Kraus, cardiologist and senior researcher. "This demonstrates the clinical significance of regular exercise in preventing the development of insulin resistance and glucose intolerance in patients at risk for diabetes and heart disease."
