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Controlling Diabetes Through Exercise

26 September, 2005

Last week a lead article in the Toronto Star appeared with the headline "New diabetes 'epidemic'". The newspaper used such strong language because 2 million Canadians already have Type II Diabetes, another 600,000 may not even know they have it and 3 million may have the disease by the end of this decade.

What led us to this epidemic? Before answering that, let's look at the disease a little more closely.

What is Diabetes?
Diabetes is a disorder that prevents blood sugar (glucose) from being properly used by your body for energy. Your body produces a hormone called insulin that lets you make use of the glucose you get from the food you eat. Insulin is produced in an organ called the pancreas.

There are three types of diabetes:

  • Type I, often called "juvenile diabetes" is a condition where the pancreas does not produce enough insulin. It accounts for about 10% of all diabetes cases. This condition appears before the age of 30 and its cause is genetic.

  • Type II, often called "adult-onset diabetes", is a condition which develops when your body becomes resistant to its own insulin. Even if you produce as much insulin as a non-diabetic, your body needs more to get the same effect.

  • A third type, gestational diabetes, affects 3.5% of non-aboriginal women but up to 18% of aboriginal women and occurs during pregnancy. Its diagnosis and treatment is the same as for Type II diabetes. Gestational and Type II diabetes together make up 90% of diabetes cases.

There is no cure for Type I diabetes. People with this condition control it through insulin injections. Type II diabetes is a different story: it is controlled by changes to diet and lifestyle, and sometimes with drugs. And unlike Type I diabetes, Type II is largely preventable.

Why is it serious?
Diabetes is difficult to treat once it develops. It is the leading cause of blindness, kidney failure and limb amputations. As well, it can lead to coronary heart disease, strokes, blood vessel and nerve damage, and infections such as gangrene.

Some important facts about Type II diabetes:

  • It is one of the leading causes of death among Canadians.

  • Diabetics are 15 times more likely to require lower-limb amputation than the general population

  • 25-45% of men with diabetes have erectile dysfunction

  • Type II diabetes is six times more common in adults over age 45 than those ages 30-44 and is very common in adults over age 65.

What Causes Type II Diabetes?
The short answer is glucose intolerance. This means that when you eat, your body doesn't produce enough insulin to process the food energy, so your blood sugar level goes too high. We don't know whether aging itself plays a role in glucose intolerance or if other changes we relate to aging do: like increased body fat, decreased muscle mass and decreased physical activity. It is now believed that a lifestyle of overeating and physical inactivity has made the biggest contribution to the increase in Type II diabetes. And physical inactivity is as strong a risk factor in complicating the disease as cigarette smoking, high blood pressure and high cholesterol.

Some good news:
We now know that exercise and diet changes can go a long way to controlling the disease. Regular exercise can help reverse the decreased insulin sensitivity we often see in older people.

How Exercise Helps
Improving your muscular strength through resistance training and cardio-respiratory endurance through aerobic exercise will help you control your diabetes. Besides maintaining and improving bone mass, resistance training will help you reduce body fat, reduce blood pressure, improve blood lipid levels, and control blood glucose (see sidebar #1). Regular aerobic exercise can also be helpful in controlling coronary heart disease and help reduce your body fat. Besides aerobic activity and resistance training, your exercise program should include flexibility and balance training.

Risks of Exercise:
Although exercise is encouraged for diabetics, it does come with some of its own risks. The most common is hypoglycemia (low blood sugar). This is more likely to occur in individuals who are taking diabetes medication, because the added demand for glucose (caused by exercising) may not have been accounted for in your dosage and diet regimen. Be sure to see your doctor before beginning any exercise routine (see sidebar #3) and be sure to tell your fitness instructor or personal trainer if you are diabetic or hypoglycemic (see sidebar #2).

Another risk factor of exercise is the chance of foot injury, which could lead to an infection from a condition called peripheral neuropathy. This is caused by damage to the small blood vessels and nerves in your hands and feet. This can mask injuries because of you may not have any of the clues your rely on, such as pain, when you stub your toe. Watch where you are walking! (see sidebar #2)

What You Should Do
The Canadian Diabetes Association recommends several things to help you manage your disease, including:

  • Screening - for high blood pressure, high glucose, and high cholesterol

  • Improving Your Diet - by eating a balanced diet high in fibre and low in fat. Be sure to include plenty of whole grains, fruits and vegetables, and get your protein from vegetable sources, fish, and lean meat. More information can be found in Canada's Food Guide. You may want to talk to a registered dietician for help with managing your food intake and food selection. More information can be found at www.dieticians.ca

  • Increasing Physical Activity - Build physical activity into your day, every day. More information on becoming more active can be found in Canada's Physical Activity Guide for Older Adults.

Remember...
Along with changes in diet and lifestyle, regular exercise can help control diabetes! It will help you lose weight, because as you become more active, you will burn more calories. And as we have seen, it will also help control your blood glucose levels.

If you are new to exercise or have a hard time staying motivated, look for exercise programs in your community that are enjoyable. You may want to talk to a personal trainer or fitness consultant to begin a home exercise program or for assistance if you join a gym.

To your health,
Chris

References

Barnes, D.E. (2004). Action Plan for Diabetes. Champaign, IL: Human Kinetics

Goulet, E.D. et al (2005). No sustained effect of aerobic or resistance training on insulin sensitivity in nonobese, healthy older women. Journal of Aging and Physical Activity, 13, 314-326.

Kriska, A. (2000). Physical activity and the prevention of Type 2 Diabetes Mellitus: how much for how long? Sports Medicine, 29(3), 147-151.

New diabetes 'epidemic'. Toronto Star, September 21, 2005

Ryan, A.S. (2000). Insulin resistance with aging. Sports Medicine, 30, 327-346.

Westcott, W.L. & Baechle, T.R. (1999). Strength Training for Seniors. Champaign, IL: Human Kinetics

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Sidebar #1:

The Role of Glucose and Insulin in Exercise
When you exercise, your cells become more sensitive to insulin, so glucose is transported into the cells at a faster rate. This reduces blood glucose levels because an exercising muscle uses the glucose stored in it for energy. When glucose is depleted, the muscle makes up for the loss by taking glucose out of your blood. This reduction in blood glucose reduces the amount of insulin you require. You will see improvements in your glucose metabolism typically within one week of starting aerobic activities. There is also a long-term effect to exercising: The more you exercise over time, the more active muscle fibres you produce. More muscle fibres mean more glucose usage. The more glucose you use, the more that is taken from your blood, keeping those levels under control. This benefit does not last, however, if you discontinue exercise. In as little as a couple of days, the effect will be reversed. That's why it is so important to be active every day!

Type I diabetics experience positive effects from exercise similar to those with Type II but for them, the changes are entirely dependent on insulin doses and diet.

Another benefit when you exercise is weight loss, which is especially a concern for type II diabetes. Weight loss will improve your overall health and decrease the risk factors for other complications of the disease .

Sidebar #2:

Take Care When You Exercise
If you are working with a personal trainer or taking an exercise class, be sure to tell the instructor that you are diabetic or hypoglycemic. He or she may have a ready supply of sugar available, such as a box of raisins or a can of fruit juice. However it is your responsibility to ensure that you are maintaining proper levels of glucose and insulin. Also, because of the risk of peripheral neuropathy, be sure to wear properly fitting shoes for exercise and be sure to wash and dry your feet properly after exercising. If you notice any infection, tell you physician. Be especially careful in exercise facilities where there may be hazards on the floor, such as weights, which haven't been properly returned to the racks.

Sidebar #3:

Talk to Your Doctor!
Regardless of the type of diabetes you have, you must tell your doctor before beginning an exercise program. Unfortunately, many physicians do not counsel their patients about the benefits of exercise in the treatment of diabetes. However, he or she should still be made aware of your intentions and tests should be done to ensure that you do no have any illnesses or conditions which may be made worse by some types of exercise. If you have any of these conditions, you will need to work with your doctor to ensure that you are able to exercise and if so, what modifications you may need to make to your regimen. Finally, you must make your personal trainer or fitness class instructor aware of any restrictions your doctor has placed on your exercise regimen.