According to the Canadian guidelines for exercise, a leisurely 50-minute walk may be as beneficial to your health as a 30-minute run.
Though I wish I’d read the guidelines before embarrassing myself on the treadmill at the PEC, Robert Ross, an exercise physiologist with the School of Kinesiology and Health Studies, said my dreams of walking my way to a wan waist have yet to be empirically supported.
“Remarkably, there’s really no solid evidence from good randomized control studies to see if that’s true or false,” he said.
Ross has received $1.8-million by the Canadian Institutes of Health Research (CIHR) to lead a study examining Canada’s exercise guidelines.
The guidelines, written in the late 1960s, suggest 20 to 30 minutes of daily vigorous activity, such as moderate to brisk jogging, offers a wide range of health benefits. The guidelines add that 45 to 60 minutes of walking can deliver the same results.
Ross said the guidelines were created when less was known about exercise science.
“The Canadian guidelines, like most guidelines worldwide, were based on intuitive observations gleaned from very little research data. The people who crafted the guidelines are outstanding scientists still today, but there was very little information available to them, so they went with their best understanding of the literature at the time.”
Ross, who got his undergraduate degree in physical education and left university with plans of teaching phys. ed and coaching football, said the study he plans to conduct over a three-year period aims to verify the information in the guidelines, something he was surprised hadn’t been done before.
“The Canadian guidelines are very similar to the American, the British, etc,” he said. “In effect, we’re not just testing the Canadian guidelines; we’re really putting to the test the whole notion that if you increase the intensity, you can decrease the duration.”
Ross said he doesn’t have any problems with the current guidelines.
“They are exactly the way they should be right now, I have no problems with them whatsoever,” he said. “I just think we need to sharpen our pencils and that’s what we’re doing.”
The study’s results will affect more than 60 per cent of Canadians who are technically obese, and is attempting to help people maximize the efficacy of the time people do spend exercising, Ross said.
Obesity is defined as a person having a Body Mass Index (BMI) of over 30. A “normal” BMI is within 18.5 to 24.9 on the scale, which is calculated by dividing one’s height by one’s weight.
“Our study fits into this given that people have busy lives. We need to maximize the time that we do have to be physically active. If we can determine that 30 minutes of walking is equal to 60 minutes of walking, that’s very important for people,” he said. “Let there be no mistake, we know if we’re physically active that’s good, regardless of how long we’re physically active for. Right now the guidelines are very vague, so we’re seeking to sharpen them a bit.”
The randomized control study will monitor 320 obese male and female adults carrying excess stomach weight, all of whom will eat the same balanced diet. The adults will be divided into three groups, each exercising for a different length of time and at various levels of intensity.
The study will test subjects’ waist circumferences and glucose tolerances over the three-year period. Ross said glucose tolerance is tested as a predictor of diabetes and cardiovascular disease, two major health risks to obese and physically inactive people.
Ross said he doesn’t know what the study will uncover.
“We hypothesize that those who are in the longer, slower group, because they’re going to expend more calories, would perhaps see a reduced waist circumference compared to other groups. They’re doing more work and they’re expending more energy. But whether that translates to metabolic risk factors, I really don’t know.”
The study’s participants are likely to see the greatest benefits from following the guidelines, because regimens will be supervised by professionals.
“Our study is an efficacy study,” Ross said. “These people are working under idyllic circumstances, and they will provide the rudimentary information—this is what happens if you do this. We can then apply that to more real world, long term studies, to find the optimal strategies.”
Ross’s study is more relevant today than ever; obesity rates in Canadian children have risen about two-hundred per cent in the past decade, while Canada is 11th worldwide in terms of general obesity. As obesity rates continue to rise, so do associated health problems such as cardiovascular disease and Type II diabetes. Health authorities fear obesity-related diseases and complications will soak up scarce health funding and damage Canada’s medical system.
“Many of the diseases we face are lifestyle-based,” Ross said. “Obesity is not a behaviour; it’s an outcome.”
Many factors contribute to Canada’s increasingly obese population, Ross said.
“There’s the problem of our increasingly sedentary lifestyles and increasingly poor diets. We’re a Western country, so we’ve engineered physical activity right out of our lifestyle, which is just the paradox of man. Man’s intelligence has created a society in which we don’t really have to extol any effort, yet the consequence of that very lifestyle is killing us.
“Canada is not unique in that regard, this is a worldwide issue,” he said. “We worry about the deaths—quite appropriately—that will result from H1N1, but the deaths that will occur from that are minuscule compared to the deaths that will occur in can over the same period due to this obeseogenic, toxic environment we live in.”
Although awareness of healthy eating and physical activity has increased over the past decades, Ross said we’ve created an environment that makes healthy choices more difficult.
“The optimal default is usually the poor behavior. You can supersize your meals for ten cents more. It’s very inexpensive to get high calorically dense food. Access to high density food is very easy, while access to foods that are better for us is slightly more difficult, and often more expensive.”
Ross added that knowledge of a lifestyle’s dangerous effects doesn’t necessarily change one’s behaviour.
“Mere knowledge didn’t change smoking at all. We knew for years that it was bad for us,” he said.
“If we’re going to stop obesity we’ve got to start addressing the behaviours. It’s what we did with lung cancer, and so too here. I trust these kinds of studies are starting to provide the info we need, but we have a long way to go. We need to convince our legislators that the time has come to perhaps appropriately tax foods that are associated with illness, and make cheaper a more positive approach.” Ross said funding trials like his is a step in the right direction.
“On a positive note, we are becoming more aware, at many levels of government and at many levels of medicine. The allied health profession is really working together, creating multidisciplinary approaches to deal with this multidisciplinary problem. I’m not discouraged. We’re very proud yet humble at the same time that we’ve received this funding.”
Ross, who works out every day, said he’s often asked how much people should exercise.
“My answer is always ‘more.’ 65 per cent of Canadians don’t meet the guidelines today, maybe seventy. The good news is going from nothing to something is a tremendous improvement and produces decreases in overall health risk.
“If someone believes they can be physically active, eat whatever they want, and enjoy the benefits of the optimal lifestyle, they’re fooling themselves. If someone thinks they can follow the food guide and do no exercise, that’s equally silly. You have to do both.”
Ross said finding an enjoyable physical activity is crucial to maintaining a healthy lifestyle.
“You need to adopt a physical activity that you will do for the rest of your life. You can’t start this for six months and then put it in the bank,” he said. “You can’t take medication to lower your cholesterol, stop them, and not expect your cholesterol to go up again.”
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