Innovation Canada | The Skinny on Exercise

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The Skinny on Exercise

Dr. Stuart Phillips
Associate Professor, Department of Kinesiology
McMaster University

Dr. Stuart Phillips completed his PhD at McMaster University, subsequently pursuing post-doctoral research at the University of Texas Medical Branch in Galveston, where he examined the interaction of amino acids and resistance exercise. He returned to establish and lead the Exercise Metabolism Research Group, dedicated to studying the intricate physiological underpinnings of nutrition and exercise. More specifically, Phillips employs biochemical tracers to follow the movement of the proteins and glucose that we consume, as well as performing biopsies on the muscles of test subjects who are engaged in specific forms of physical activity. His goal is to gain a better understanding of how diet, exercise and certain forms of movement combine with our genetic makeup to affect the loss or addition of muscle mass.

Treadmill

McMaster University’s Exercise Metabolism Research Group uses treadmills similar to those produced by the Wisconsin-based manufacturer Woodway. These machines vary the amount of a user's body weight that can be supported, making it possible to conduct cardiovascular activities such as running or walking despite physical restrictions.

Mass Spectrometer

A mass spectrometer determines the physical composition of materials by distinguishing and displaying the various molecules they contain. Widely used in traditional disciplines like chemistry and biology, this technology has seldom found its way into laboratories examining the physiological impact of exercise.

Blood lipids

The bloodstream contains lipids, or fats, that carry out essential metabolic functions. Two of the most important lipids are cholesterol, which maintains the structure and function of cells, and triglyceride, which transfers the energy derived from food to the cells. Vital as these lipids are, if they occur in excess, they can build up on the walls of arteries, ultimately blocking the blood supply to the heart, brain, and other vital organs.

Glucose tolerance

Glucose tolerance is a measure of how quickly the body clears glucose, or sugar, from the blood, which indicates other aspects of metabolic function, especially underlying chronic conditions like diabetes.

Lean body mass

Lean body mass refers to the combined weight of everything other than fat in the body, including bones, muscles, and organs. The term does not refer to one’s ideal weight, that is, what you would weigh if you were “lean.”

Innovation Canada | Dr. Maureen MacDonald

Dr. Maureen MacDonald
Assistant Professor, Department of Kinesiology
McMaster University

Dr. Maureen MacDonald completed her PhD at the University of Waterloo, working with one of the pioneers in the application of ultrasound imaging technology to exercise physiology. This approach makes it possible to measure the movement of blood vessels in individuals while they are engaged in physical activity. The resulting data can be used to examine issues like the stiffening of arteries and their links to cardiovascular disease, a subject MacDonald studied as part of her post-doctoral work at the University of British Columbia. She continues to explore questions surrounding arterial structure and function, not just to improve our basic knowledge of the cardiovascular system and the impacts of exercise, but ultimately, to satisfy society’s search for a healthy lifestyle.

Doppler ultrasound

The Doppler shift is a change in the frequency of a sound wave that occurs when the receiver of a sound is moving relative to the source of that sound. Medical technicians harness this effect using ultrasound technology, which emits high-frequency sound waves to create images of structures and movements inside of living organisms. When these sound waves are reflected from red blood cells in an artery, for example, the resulting data can be used to calculate the velocity of the blood and assess how well this artery is performing.

A McMaster University researcher shows that even a little exercise can produce results, no matter what shape you’re in.

By Tim Lougheed

Visions of sugar plums may be fine during the holidays, but for many of us, the New Year usually brings dreams of tighter butts and six-pack abs. All too often though, these dreams disappear faster than Valentine’s Day chocolates.

Our ambitions need not end so soon, according to Stuart Phillips. As an investigator with McMaster University’s Exercise Metabolism Research Group, Phillips marvels at how much we benefit from even the most modest levels of physical activity, and how readily anyone can maintain lifelong fitness.

“We all retain the ability for our muscles to respond to exercise,” he says, noting that this ability transcends the effects of aging or injury. “It’s not something that takes weeks, months, or years to see a change—it happens within days.”

Phillips has assembled remarkable evidence for this conclusion in his laboratory—a facility he and his colleagues have spent the past eight years outfitting. The resulting combination of technology and expertise lets researchers investigate exercise dynamics in unprecedented physiological detail.

In particular, Phillips has studied the effect of exercise on individuals with crippling spinal cord injuries. Participants were suspended over a treadmill, enabling them to work out even with their paralyzed limbs. Thanks to equipment like powerful mass spectrometers, researchers were able to assess factors such as bone formation, changes in blood lipids, and glucose tolerance.

These measurements revealed that the participants had significantly increased their lean body mass. The higher your lean body mass, the more efficiently you can burn calories. Despite their paralysis, the research subjects also increased the size of their leg muscles, which responded positively to the activity.

Equally striking insights emerged from another experiment, in which young men who didn’t exercise regularly followed a comprehensive weight-training regime, five days a week for three months. Participants saw a 50-percent increase in the amount of weight they could lift and an increase in their lean body mass.

Nor is age a barrier to progress. Another lab member, Maureen MacDonald, uses Doppler ultrasound detectors to take stock of how key blood vessels perform during a workout. She looked at a group of men in their sixties, asking them to conduct simple hand-grip exercises for a few minutes a day.

“We showed that with eight weeks of this training, their resting blood pressure dramatically decreased,” she says, noting the same effect occurs even among individuals who take medication to control high blood pressure.

These findings mean good news for all of us—they demonstrate how quickly we can see results, regardless of our age and previous physical condition. In addition, Phillips says results actually come during periods of rest and recovery as our bodies rebuild and adapt to the work they have already done.

His latest research has also revealed that one of the most helpful parts of our diet could also be one of the most familiar—a plain old glass of milk. Using test subjects who consumed different beverages after athletic workouts, Phillips compared the effect of milk with that of popular soy-based or carbohydrate-loaded products.

The outcome was extraordinary: over 12 weeks, the milk drinkers, on average, lost nearly twice as much fat as those drinking carbohydrate beverages, and those drinking soy lost no fat at all. At the same time, the milk drinkers gained significantly more muscle mass than the others.

Phillips is still considering the metabolic processes that make milk the ideal post-workout drink and plans to further research milk’s key components, including the calcium, vitamins, and proteins found in whey and casein. But he is pleased to have discovered that one of our most venerable foodstuffs can hold its own against heavily marketed synthetic products. “Sometimes you come back to basic, simple ideas, and lo and behold, there’s something there,” he says. “There’s nothing revolutionary in exercise—nothing. And there’s nothing revolutionary in diet.”