The Diabetic Athlete

By Terry Zeigler, EdD, ATC

Diabetes is a common chronic disorder that affects millions of people. Diabetes is a metabolic disorder characterized by the inability of the pancreas to produce enough insulin. The disorder does not have a cure, but can be managed if the individual is careful with their diet, exercise program, and use of insulin (if insulin-dependent).

There are two general categories of diabetes. Juvenile onset diabetes (also known as type 1 diabetes) is characterized by an early onset (under the age of 25) hence the name “juvenile”. The onset is usually sudden with symptoms occurring within a time frame of several days to several weeks. Individuals diagnosed with Type I diabetes are insulin dependent and will need to administer insulin on a regular basis to keep their blood sugar levels at a healthy level.

Type 2 diabetes is the most common form of diabetes and is typically linked to a family history of diabetes, obesity, and lack of exercise. The age of onset is usually after 40. If caught early, type 2 diabetes can be managed with a healthy diet and good exercise program without the need for additional insulin.

Whereas the cause of type 1 diabetes is unknown, the cause of type 2 diabetes is well documented. According to Anderson, M., Hall, S., & Martin, M. (Sports Injury Management, 2000), obesity affects nearly 90% of adults with type 2 diabetes. The amount of insulin needed to maintain normal blood glucose levels increases as body fat increases. Although insulin is produced by the body, insulin receptors are reduced in their number and ability to function properly. The end result is that the body cannot supply enough insulin to keep up with the demands of the body.

Individuals that are obese either due to poor eating habits and/or lack of exercise are at risk for type 2 diabetes. Regular exercise and maintaining a healthy body composition (ratio of body fat to lean tissue) are important for preventing the onset of type 2 diabetes.

Although there once was a time when an individual with diabetes was discouraged from competing in sports, athletes are now encouraged to participate in all types of sports and activities. The key for the diabetic athlete is to balance his/her blood sugar levels by carefully monitoring his/her food intake, insulin levels, and activity levels.

Blood sugar levels will rise and fall throughout the day as food is eaten. As food is consumed, the blood glucose levels rise. The level of the increase depends on the type of food that is eaten. For this reason, athletes with diabetes need to eat foods rich in carbohydrates, but with a low glycemic index (less than 55). These types of food include:

• High-fiber fruit (apples, oranges)
• Fruit juices
• Legumes
• Milk
• Most whole-grain multigrain breads
• Most pastas

These types of foods gradually raise the blood glucose levels as compared to foods that result in a sharp increase in blood glucose like simple carbohydrates found in cookies, cakes, chips, sodas, and most junk-food.

Diabetic athletes need to take care to eat a meal rich in complex carbohydrates an hour before exercise and then be able to supplement these calories with additional snacks during the competition as needed. Snacks such as fruit juices, fruit, yogurt, and crackers should always be kept readily available for these athletes in case their blood sugar drops.

Monitoring blood glucose levels is an important part of managing diabetes for an athlete. Normal blood glucose levels should range between 80mg/dL and 120mg/dL. Athletes should monitor their blood glucose before, during, and after activity to ensure that their blood glucose stays within a normal range. Athletes whose blood glucose levels drop below 70mg/dL should not exercise or compete until their blood sugar level is raised to within the normal range.

Insulin dependent athletes can either inject insulin throughout the day to balance their food intake or use an insulin pump. The advantage of an insulin pump is that the device replaces the need for insulin injections. Through the use of a catheter inserted just under the skin, the insulin pump delivers insulin continuously throughout the day to meet the needs of the individual. Extra doses can be given after eating to manage the associated rise in blood glucose levels.

Depending on the sport/activity, the insulin pump can either be worn in a strong elastic waistband or attached to a sports bra in females. If the athlete competes in a contact-type of sport, the device can be removed during the activity and reattached when the activity is done.

Problems with the diabetic athlete can occur if there is a drop in blood glucose (hypoglycemia) or a rise in blood glucose (hyperglycemia). Those who work with diabetic athletes need to be aware of both.

Hypoglycemia can be brought on by the athlete not eating enough carbohydrates prior to activity and then participating in intense exercise. Low blood glucose levels result in a condition called “insulin shock”. The signs and symptoms of hypoglycemia include:

• Dizziness
• Headache
• Intense hunger
• Pale and clammy skin
• Confusion/disorientation
• Physical weakness

When this condition is recognized, the first questions that need to be asked are “Have you eaten today and when?” and “Have you taken your insulin today and when?” If the athlete has not eaten in a while, he/she should immediately be given a sugared beverage, fruit juice, or pack of honey. These will provide quick sugar to the athlete’s system and his/her symptoms will reverse quickly.

Hyperglycemia is the opposite of hypoglycemia. The athlete’s blood glucose gradually rises over time (24 hour period) as a result of insufficient insulin. This condition can result in a diabetic coma. The signs and symptoms are distinct and include:

• Fruity-smelling breath
• Nausea/vomiting
• Labored breathing
• Dry mouth
• Flushed skin
• Confusion
• Unconsciousness followed by coma

This condition is only reversed by providing the athlete with insulin. An injection of insulin usually prevents the individual from lapsing into a coma. This condition is a life-threatening one and one in which emergency medical services should be immediately called.


American Diabetes Association. (accessed 2.10.10). Insulin Pumps.

Anderson, M., Hall, S. & Martin, M. (2000). Sports Injury Management. (2nd Ed.). Lippincott Williams & Wilkins: Philadelphia, PA

Prentice, W. & Arnheim, D. (2008). Essentials of Athletic Injury Management. McGraw Hill: New York, NY.

Shugart, C., Jackson, J., & Fields, K. (January/February 2010). Diabetes in Sports. Sports Health.