The Effects of Weight Lifting on Glucose Readings

Weight lifting can affect your blood sugar levels hours after exercise.
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Exercise is important for everyone, including people with both types of diabetes. The types of exercises you do, as well as the type of diabetes you have, has an important impact on how your body handles glucose while you exercise. Weight lifting uses glycogen stored in your muscles for fuel, but weight-lifting can also trigger the release of hormones that sends more sugar into your bloodstream.

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How the Body Uses Glucose

When you consume food, especially carbohydrates, your body changes the glucose from the food into a form of energy the body can use, called glycogen. This primary source of energy is stored in your muscle cells. When that glycogen runs out, your body then turns to glucose in your bloodstream. Check your blood glucose levels 30 minutes before and just prior to exercise to monitor your blood level trend. According to Johns Hopkins Medicine, an acceptable blood sugar reading for exercise is between 100 mg/dL and 250 mg/dL.


Monitor Blood Glucose During Weight Lifting Sessions

Cardiovascular exercise is a common way for your blood glucose level to dip as your body uses the glucose for energy. However, weight lifting and other exercises that require short bursts of energy have a different effect on blood glucose. These short bursts of energy can provoke the adrenal glands of the body resulting in a "fight or flight" response by your body. When this happens, your body temporarily releases more glucose into your bloodstream. Check your blood sugar readings every 30 minutes during workouts longer than an hour or if you are trying a new or more strenuous workout routine. Stop exercising and check your blood sugar immediately if you have symptoms of low blood sugar -- feeling faint, palpitations or weakness.


Circuit Weight Training

Circuit weight training has beneficial effects for individuals with Type II diabetes, according to Jeffrey Janot and Len Kravitz in "Training Clients with Diabetes." Performing a series of upper- and lower-body weight-lifting exercises can lead to improvements in glucose control through increased muscle mass, or hypertrophy. Recommended exercises include arm curl, military press, bench press, squats, knee extensions, heel raises, back extensions, and bent knee sit-up. Perform one set of 10 repetitions of upper-body exercises and one set of 20 repetitions of lower-body exercises twice a week. Rest 30 to 60 seconds between sets.


Weight Lifting and Food Consumption

You should not exercise when your blood sugar is at its peak, according to Johns Hopkins Medicine. In general, eating one to three hours before exercise is best. If your levels are below 100 mg/dL, eat a small carbohydrate snack before you exercise. Do not exercise if your blood sugar readings are higher than 300 mg/dL. Avoid exercising just before going to bed to avoid low blood sugar during the night, as your muscles continue to burn glycogen for hours after exercise. Consult your medical provider before you begin your exercise program for guidelines specific to you.


Is This an Emergency?

If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911. If you think you may have COVID-19, use the CDC’s Coronavirus Self-Checker.