Gilles Beaudin
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It was a first for me. I could not believe it. This patient did not fit the usual profile. He was young, had some muscle and wasn't overweight. He was sitting in my office, unaware of the danger he was in. His fasting blood sugar was twice the acceptable value.
Hyperglycemia, or high blood sugar, is an expressway to diabetes. This is not something to take lightly. Your blood sugar can be twice the recommended level, and yet you would be feeling fine. The nasty work happens behind the scenes, attacking every tissue in your body. My colleague, Cleveland Clinic Canada endocrinologist Dr. Jeremy Gilbert, tells me that diabetes is the No. 1 cause of non-traumatic amputations in Canada.
Let me explain the blood sugar process. After a meal, glucose enters the blood. Under the action of insulin, it goes to one of three places: the liver, muscles or fat cells. When the first two are full, the extra gets stored as fat. If you abuse the power of insulin, your body builds an opposition to it.
How do you abuse the power of insulin? The partial answer is eating large meals, skipping meals and eating too many refined carbohydrates. Gradually, after many years of abuse, your muscle and fat tissues will resist the insulin action. You can slowly develop insulin resistance and sugar will stay in your blood longer than it should. In most cases, this is the precursor to hyperglycemia or prediabetes.
Before I go any further, I cannot overstate the importance of food choices. This is paramount to your long-term health. It can be hard to navigate this nutritional mine field, since processed sugar finds its way into so many foods. If you need guidance, a registered dietitian will point you in the right direction.
Clearly, your first line of defence is what you eat. But what about exercise?
Muscles use glucose when they are being exercised, so it is extremely beneficial. The general advice is to go for a walk. And it works, but your blood sugar will likely rise again at the next meal. The key to longer-term benefit is resistance training, for it will actually modify the architecture of your muscles.
Researchers out of Kansas City reported that resistance training was associated with better glycemic control than treadmill exercise. Here's why.
Allow me to get a little technical. (Don't worry, it won't be too painful.) Your muscle cells have glucose transporters called GLUT4. They are activated by the action of insulin on the muscle cell membrane. GLUT4s come to the surface to move glucose from the bloodstream to the inside of the muscle cell to be used for energy or stored for later.
Now think about it: Most cardio exercise is done using mainly the leg muscles. And it is rarely done in a way that involves most of the muscle fibres. On the flip side, most people do resistance training for lower and upper body, which results in more muscles that are challenged close to fatigue. When more fibres are put to work, the result is an increased storage capacity for glucose.
When this process is repeated every week, your muscles adapt. They will become more sensitive to insulin and, you guessed it, will create more GLUT4. If you force your muscles to part with their glucose reserves, they want more. All they want is to be ready for the next challenging workout.
Can you do that for them? It's all up to you.
Gilles Beaudin is a registered clinical exercise physiologist at Cleveland Clinic Canada.