Written by Brian B. Parr, Ph.D.
Diabetes mellitus is a metabolic disorder characterized by high blood glucose (sugar) caused by a lack of insulin production or impaired insulin action. Insulin is a hormone produced by the pancreas that regulates blood glucose by causing the body’s cells to take glucose out of the blood. There are three major types of diabetes:
- Type 1 diabetes is usually diagnosed in childhood. Damage to the pancreas by the immune system results in a lack of insulin production, so type 1 diabetics require insulin injections.
- Type 2 diabetes tends to occur in adults and is associated with being overweight, particularly in the abdomen. In type 2 diabetes, the pancreas produces insulin but the cells do not respond to it (insulin insensitivity).
- Gestational diabetes occurs during pregnancy in women who are not diabetic.
Although this condition tends to resolve itself after childbirth, it may lead to a higher risk of type 2 diabetes in the future.
Diabetes is diagnosed based on blood glucose level and symptoms including excessive thirst and hunger, frequent urination, blurred vision, and weight loss. It is estimated that more than 20 million Americans have diabetes, the vast majority of which are type 2. Additionally, another 50 million have pre-diabetes, meaning that blood glucose is above normal but not high enough to meet the criteria for diabetes. Pre-diabetes often leads to developing diabetes in the future.
In all types of diabetes, control of blood glucose through diet, exercise, and medication is essential. Over time, high blood glucose levels can cause nerve and blood vessel damage leading to vision problems, lack of sensation in the hands and feet (neuropathy), kidney damage, and poor wound healing. In fact, diabetes is a leading cause of blindness, foot amputation, and kidney dialysis and transplants. Additionally, type 2 diabetes tends to be associated with high blood pressure, high triglycerides, low HDL (good) cholesterol, and obesity. This combination is called the metabolic syndrome. Furthermore, diabetics are at higher risk for heart disease and stroke. The treatment of diabetes involves several approaches: blood glucose testing, proper use of medications, planning healthy meals, and regular exercise.
Blood glucose is typically tested several times throughout the day in order to maintain normal blood glucose levels. Type 1 diabetics (and some type 2 diabetics) require injections of insulin. Type 2 diabetics may also take medications known as oral hypoglycemics, which also lower blood glucose. In order to be effective and to prevent hypoglycemia (abnormally low blood glucose), medications must coordinated with meals, exercise, and other activities.
Exercise is important for blood glucose control because exercise causes an increase in the uptake of glucose into cells and can improve glucose tolerance and insulin sensitivity. In addition, exercise has the added benefits of promoting weight loss and improving strength and fitness. Some specific recommendations include:
- Test blood glucose before exercise. If it is too low, additional carbohydrates should be consumed prior to exercise. If it is too high, exercise should be postponed.
- Keep a record of blood glucose before and after exercise, including when food and medications were taken and the type, duration, and intensity of exercise.
- Include endurance, strength, and flexibility exercises in the workout regimen.
- Make exercise a daily habit to gain the greatest benefits and to make it easier to plan meals and medications.
- Wear comfortable, supportive shoes and socks to minimize the chance of foot injury. After exercise, inspect feet carefully and treat sores to prevent infection.
Be mindful of diabetic complications. Avoid very strenuous exercise, especially weight lifting, which could raise blood pressure and be aware that impaired sensation in the fingers may make measuring heart rate difficult.
Meal planning involves selecting healthy foods to help maintain consistent blood glucose levels while meeting energy needs for exercise and other activities. The diet should also promote weight loss and weight maintenance, especially for overweight patients. Some recommendations:
- Include a variety of whole grains, fruits, vegetables, and low-fat dairy and meat in your diet.
- Minimize the intake of saturated fat, cholesterol, and sodium, especially if you have high cholesterol or high blood pressure.
- Both sugar and alternative sweeteners are safe when consumed in moderation, as part of a healthy diet.
- Plan meals with regard to medications and exercise. Extra snacks may be needed before or after exercise.
Proper diet, blood glucose testing, medication use, and regular exercise can improve blood glucose control, reduce the risk of other health problems, and improve quality of life in diabetics. In those with prediabetes, these efforts can delay the progression to diabetes and may even result in a return to normal blood glucose.
View the full spring 2008 issue of the ACSM Fit Society® Page online.