PNFM News & Articles

Diabetes & Sports

Exercise is vital to diabetes control. The key thing to keep in mind with diabetes is that metabolism, particularly the way the body controls blood sugar (glucose) levels, is different from the metabolism of others. In “Type 1” Diabetes, this difference often results from the body's self destruction (auto-immune destruction) of insulin-producing cells in your pancreas. This lack of insulin limits your body's ability to pull sugar from your blood stream. In “Type 2” Diabetes, the problem usually lies in the response of your body’s tissues (such as muscle) to insulin. Regardless of Diabetes type, the body does not properly regulate the level of sugar in the blood. This can cause damage to blood vessels and nerves throughout the body. Hence, Diabetes is a major risk factor for heart attack, stroke, wounds, infections, trouble seeing and decreased sexual performance. It can also compromise safety during certain types of exercise. However this does NOT mean diabetics cannot exercise or play sports. There are world class athletes who are diabetic. They enjoy life and function at elite levels by working with health providers to understand their condition. They also develop maintainable strategies to exercise safely.

Exercise Metabolism Basics

The body has different stores of energy. For example, muscles have glycogen and triglycerides which are sources of glucose. The liver stores glycogen which is turned into glucose for release into the bloodstream. Body fat can be broken down into fatty acids. Your body is smart enough to know which sources to use for certain exercises. It can also switch energy sources based on the phase of exercise. For example, ATP (adenosine triphosphate) and phosphocreatine are main energy sources for short burst activities such as 200 meter sprints. Endurance activities like long runs call for free fatty acids as a main energy source.

During exercise the body needs readily available glucose. It lowers insulin and increases levels of glucagon, cortisol, and growth hormone in the blood. Glucose is taken up by muscles for energy. The nervous system plays a part in regulating these changes. There are also other factors at play. After exercise, muscle glycogen (stores of sugar) and liver glycogen (stores of sugar) are restored using glucose available in the blood. This is important for recovery and for the next exercise session.

Although glucose is needed for energy, there has to be a balance. Too much or too little blood sugar can be dangerous. Too much blood sugar, or hyperglycemia, can affect all diabetics. If glucose levels are high and the body’s tissues are not responding to insulin (either because insulin is not available or tissues are not fully responding to insulin) then your body’s tissues think there is not enough glucose. So your body will trigger emergency responses to compensate. Liver glucose production, fat breakdown, and ketone production can go “unchecked”. This simply creates more sugar in the blood stream along with breakdown products (ketones). This is a dangerous change in the makeup of your blood. It can cause fatigue, headache, dizziness, vision changes, shortness of breath, kidney failure, muscle aches, nausea, stomach pain, chest discomfort, mental changes, seizures, and coma. Diabetics who do not watch their food intake, fluid intake, or blood sugar levels are at risk for these problems. Not taking prescribed diabetes medications is another risk factor.

Low blood sugar, called hypoglycemia, is more likely for insulin-dependent diabetics. It can happen to anyone, including non-diabetics. Diabetics who take too much insulin are at risk for low blood sugar. This can occur over hours to a couple of days. For complex reasons relating to hormone balance, folks with one episode of hypoglycemia are prone to have it again. Signs of hypoglycemia can include weakness, tiredness, sweats, palpitations (skipping, racing, or pounding heart beats), lightheadedness, headaches, vision changes, and even seizures (in severe cases). Other folks are less likely to experience hypoglycemia though failure to get in enough calories, carbs, or rest could certainly put them at risk.

What is a “Safe Zone” for Blood Sugar and How Do You Reach It?

The short answer – it depends. This is where strategy is key. One task is to establish your health team. I recommend professionals who are formally trained (credentialed or certified) and who are knowledgeable about diabetes. Your team should include a physician. Community professionals such as Nutritionists, Health Coaches, Behavioral Therapists, and Personal Trainers can be very helpful. They can help you pick the right kinds of fuel for your body. They can help you start exercises and to develop habits that help your body control your sugar levels. Issues with sleep and stress should be addressed. Ideally, your team members would work together to develop a personalized plan for you.

A complete physical exam is a good start point. Labs including sugar levels, sugar control markers (such as Hemoglobin A1c), lipids (cholesterol), urine, and blood markers related to organ function (for example, a kidney panel) should be checked. Other tests might be performed. Talk to your doctor about how often you should check your blood sugar at home. You might also need to check blood sugar during exercise. Find out how often you need to have office visits and lab tests. With time your team can figure out your blood sugar patterns and ways to keep it under control.

Can You Play Sports with Diabetes?

Yes. Folks with diabetes can still be elite athletes. They’re often very attentive to their health. However, certain sports carry more risk than others. This is where risk assessment with your doctor is vital. Findings from your exam, history, and lab/test results come into play. If you have nerve damage from diabetes then your doctor might advise you to avoid certain activities. This is because of the higher risks for problems like foot ulcers, trouble getting your heart rate up, and fainting (for example, due to blood pressure drops after quickly standing up). Extremes of weather are also risky. The body's ability to adjust blood flow in the heat or cold is compromised. For folks with eye disease, specifically blood vessel damage, activities that increase eye pressure can make things worse. This includes squats, heavy weight lifting, and high impact aerobics. Diabetes can cause a lot of problems. A detailed health strategy is the best way to avoid them.

Safety Tips
  • Develop a Meal Plan - Work with your health team to figure out your calorie, carbohydrate, protein, and fat needs. Meal timing is key. You might need to eat certain foods shortly before exercise or competition
  • Stay Hydrated - Dehydration can occur over hours to days. It can happen in any weather. Risk is higher if you recently had a fever. Fluid needs depend on the person, activity, medical history, and other factors.
  • Stick to Your Exercise Routine - This helps maintain your normal blood sugar patterns. Try to exercise regularly. This makes it easier to figure out the right amount of carbs and insulin (for those who need it) per day. If you are sick then call your doctor about whether you should exercise.
  • Develop a Sleep Schedule – Easier said than done!
  • Respect the Weather – If it’s hot or humid then take more breaks, keep cold water available, and take advantage of shade. If it’s cold then wear layers and take breaks as well. Wearing the right clothes/gear is important. Discuss this with your doctor and coaches. Follow these tips for indoor sports as well.
  • Check Your Blood Sugar - Figure out when and how often with your doctor.
  • Know Your Numbers - If your sugar is high or low then check with your doctor and qualified team staff (such as the Team Doctor or certified Athletic Trainer) about whether you should exercise/play. For insulin users, your doctor might decrease your insulin dose prior to exercise, so make sure you have specific instructions. For activity longer than 1 hour, your doctor might want scheduled sugar checks (for example, every 30 minutes).
  • Know Your Warning Signs - Signs of blood sugar problems can be subtle or obvious. They include headache, dizziness, vision change, unusual hunger/thirst, trouble breathing, chest discomfort, stomach pain, and fuzzy thinking to name a few.
  • Stay Prepared - Keep supplies and extra batteries in a safe, nearby place. Have things like hard candy, glucose tabs, and glucagon handy for low sugar spells. If you use an insulin pump then make sure the pump stays intact, even if you have to take it off for contact activity (like football). Wear a bracelet that can alert others if you get into trouble and can’t speak. If you're on a team with medical staff then you should have a team action plan for emergencies.

Diabetes control can be challenging. With health guidance and strong focus one can reach high levels of performance.

-- Dr. Westly Bailey

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Dr. Westly Bailey is a non-operative Sports Medicine and Family Medicine physician with Perimeter North Medical Associates. Visit for more information or call 770-395-1130


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