Of 592 middle-aged Australian adults, those who increased the number of steps they took during a five-year period and built up to 10,000 steps per day had a lower body mass index, less belly fat, and better insulin sensitivity than their counterparts who did not take as many steps daily during the same time period.
A hallmark of diabetes, insulin resistance occurs when the body's cells stop responding as well to the action of the hormone insulin, which helps the body use blood sugar (glucose) for energy. The pancreas tries to compensate by producing more insulin, but ultimately fails to keep pace. As a result, excess glucose builds up in the bloodstream, setting the stage for diabetes.
Weight loss is known to increase insulin sensitivity, so researchers suggest that increased walking led to weight loss and decreased body fat which, in turn, improved diabetes risk factors.
“These findings, confirming an independent beneficial role of higher daily step count on body mass index, waist-to-hip ratio, and insulin sensitivity, provide further support to promote higher physical activity levels among middle-aged adults,” conclude researchers, who were led by Terry Dwyer, MD, director of Murdoch Children’s Research Institute of Royal Children’s Hospital in Melbourne, Australia. “The use of a pedometer for measuring physical activity allows quantification of the magnitude of these effects.”
Participants answered questions about their diet and other lifestyle factors and had a full physical exam when the study began. They were also asked to wear pedometers to count the number of steps they took each day. Researchers followed up with the study participants five years later to see how many steps they were taking, and reassessed their diabetes risk factors.
Those who built up to 10,000 steps a day and kept at it showed a threefold improvement in their insulin sensitivity at five years, when compared with participants who only increased their daily steps to 3,000 per day, the study showed.
“This is an interesting article, and the implication is theoretically enormous,” says Gerald Bernstein, MD, the director of the Diabetes Management Program at the Friedman Diabetes Institute at Beth Isreal Medical Center in New York City.
“Activity of daily living or moving more has a positive effect on insulin sensitivity, which is a big problem in people with diabetes and prediabetes,” he says.
“There is a real basis to the science from the test tube to the real world that if you move around, you do something good in terms of insulin,” he says. “Insulin production and sensitivity deteriorates with age, so over five years we don’t expect things to be as good as they were during that first year. The fact that insulin sensitivity had improved or sustained itself in the new study is important because a period of time had passed.
“Whenever you can, walk,” Bernstein says.“If you walk 10 blocks instead of taking a bus and do it in both directions, that is already one mile."
Doctors need to talk the talk and patients need to walk the walk, says Joel Zonszein, MD, a professor of clinical medicine at Albert Einstein College of Medicine and the director of the Clinical Diabetes Center at Montefiore Medical Center, both in New York.
“Exercise is always healthy and doctors always tell patients ‘you need to exercise more’, and this study shows that persistent exercise over five years is beneficial,” he says.
“Patients who continue to exercise do better,” he says.
Making lifestyle changes and sticking with them is not always easy, he says. “Some people like the gym, and some people like to walk, so we need to give an exercise prescription and follow up to see what happens, and then maybe adjust the dose."
Is It the Weight Loss or Exercise That Lowers Diabetes Risk?
Lawrence Cheskin, MD, director of the Johns Hopkins Weight Management Center at the Johns Hopkins Bloomberg School of Public Health in Baltimore, says the new study results are likely generalizable to the U.S. population.
“We know that any time you lose weight, you will have improvements in insulin sensitivity and one of the hallmarks of diabetes is insulin resistance or insensitivity,” he says.
But taking extra steps does not always lead to weight loss, he says.
“I wouldn't conclude that if you start taking a few more steps a day, you are going to make diabetes go away,” he says. “That is a reach, but losing weight will help prevent or treat diabetes.”
Sheri R. Colberg, PhD, an exercise physiologist at Old Dominion University in Norfolk, Va., and an American Diabetes Association spokeswoman, says taking extra steps can help improve diabetes control even in the absence of weight loss.
“It’s a good idea to walk or exercise more, but this may not necessarily lead to weight loss, but it will help improve insulin action and diabetes control,” she says. Physical activity may lead to changes in body fat composition instead of weight loss, and these changes may help prevent or treat diabetes.
Terry Dwyer, author of the study, says in an email to WebMD,“There is evidence that routine changes that are not too difficult to introduce if a person is motivated such as use of cars -- switching to walking when possible -- or climbing steps at work rather than taking the elevator, can help. A more aggressive approach involving taking up an exercise program can also, of course, help.”