Exercise demands a larger amount of fuel for energy production than at rest. One primary source of energy during exercise is your blood sugar. Even without producing the hormones to move glucose from your blood and into the working muscles, your glucose can be used for energy. Diabetics and certain non-diabetics must be aware of their glucose before and after exercise to avoid low blood sugar.
Hypoglycemia
Hypoglycemia is the condition of an abnormally low blood glucose. This occurs when your glucose drops below 70 milligrams per deciliter, or mg/dL. You can identify hypoglycemia also by the symptoms that it produces. If you begin to feel fatigue, anxiety, moodiness, excessive sweating, hunger, shaky or dizzy after exercise, you may have low blood sugar. Take action by eating a carbohydrate-rich snack like 4 ounces of juice or soda, 8 ounces of milk or five pieces of hard candy.
Diabetics
When you have diabetes, it means you do not have full control over your blood glucose. The food you eat and the activity you do can affect your blood sugar. For a diabetic, exercise can offer great control over long-term blood glucose levels and can even improve the body's ability to clear blood glucose at rest. However, diabetics are at an increased risk of suffering from hypoglycemia after exercise. Check your blood sugar before exercise. If it is less than 100 mg/dL, you must eat a carb-rich snack until your glucose rises above 100 mg/dL. Test your blood glucose after exercise as well. Be sure it is in a normal resting range for you or take appropriate action if it is not. Stick with a regular exercise plan to keep the reaction of your blood glucose predictable.
Mechanism
Exercise has the ability to move glucose from your blood and into your muscles, even if insulin is not present. As you contract your muscles over and over again, it signals receptors inside of your muscle cells. These receptors move the the exterior of your cells to draw sugar in from the blood. This mechanism allows your muscles to utilize the glucose in your blood for energy, even when insulin is not around. Even in a healthy person, insulin reduces during periods of activity. Therefore, exercise can be sustainable with the help of blood glucose.
Non-Diabetics
A non-diabetic can be diagnosed with a condition known as reactive hypoglycemia. In these individuals, the pancreas produces an excessive amount of insulin. This can lead to a larger than normal movement of glucose from the blood and into your cells. Increased production of insulin, paired with the mechanical mechanism of glucose removal from your blood during exercise, can set you up for hypoglycemia after your workout. Again, check your blood glucose before and after exercise to prevent a dangerous hypoglycemic reaction.
References
- "ACSM's Guidelines for Exercise Testing and Prescription"; Mitchell H. Whaley, Ph.D., et al.; 2006
- "Exercise Physiology: Human Bioenergetics and Its Applications"; George A. Brooks, et al.; 2005
- NetDoctor: Hypoglycemia (Low Blood Glucose) In Non Diabetic People; Dr. Patrick Davey
- National Diabetes Information Clearinghouse; Hypoglycemia; 2008
