To Snack or Not to Snack: Physical Activity and Hypoglycemia Prevention

AADE Program Session
Thursday, August 12, 2004
4:30 – 5:30 PM

Reviewed by Joelle Escoffery, PhD

This program session addressed physical activity regimens and the prevention of hypoglycemia. During physical activity, there is an increased fuel demand, which in turn causes an increase in the release of hepatic glucose and insulin receptor sensitivity, and ultimately results in a decreased need for insulin. After physical activity, the need changes to fuel storage, although there is a continued insulin receptor sensitivity, which may last for 24 to 48 hours after activity. These effects place some patients at risk for hypoglycemia.

When assisting patients in creating an appropriate physical activity regimen, there are several important issues to discuss.  First, patient risk of hypoglycemia should be addressed. Hypoglycemia is really only a concern for patients who are treated with insulin or insulin secretagogues. The risk is greater for patients with autonomic neuropathy, gastroparesis, or those taking beta blockers because they may be more prone to hypoglycemia unawareness or erratic glucose levels, and extra care should be taken when addressing hypoglycemia concerns in these populations. Next, timing and intensity of activity should be addressed. Many patients do not realize that everyday activities, even lower intensity activities, such as standing, walking, and housework, burn calories. One useful strategy is to help patients graph out their activity for a given day. Patients should also be educated on the most common causes of hypoglycemia, including taking too much insulin, delaying eating, or delaying treating symptoms of hypoglycemia. Additionally, they should be made aware of the most common symptoms of hypoglycemia, including trembling, pounding heart, difficulty concentrating, and lack of coordination. When setting patient post-exertion glycemic targets, some factors to consider include time of activity, what insulin or medication will be acting during the activity, and what adjustments to medication or snacking will be made to account for the activity. Snacks should be consumed 15 to 30 minutes before exercise and every 45 to 90 minutes during exertion and should consist of 15 to 30 grams of carbohydrate for every 30 to 60 minutes of physical activity. Then, post-exercise glycemic levels should be checked, and appropriate adjustments should be made. Although a post-activity target of 100 mg/dL is advocated, that may not always be the most appropriate target, especially for people who have special considerations such as hypoglycemia unawareness.