Back to Sports Corner Top 10 Exercise Traps and Tips to Avoid Them

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Exercising with diabetes can lead to unwanted traps and decreased performance. Taking a lead from David Letterman's top ten lists these recommended points can help anyone who has diabetes and wants to exercise.

  1. Poor Performance
    For the best performance and safety keep your blood sugars between 100 and 150 mg/dl [5.5 - 8.3 mmol/L) during exercise.
    Tip - After speaking with your healthcare team, adjust your insulin and/or carb levels prior to exercise.

  2. Dehydration
    Stay well-hydrated especially when you are out in the sun. Exercise can cause significant fluid loss. Choose your beverage wisely. Caffeine can compound the problem. Sports drinks are only needed when you exercise more than an hour or if the weather causes you to sweat more than normal.
    Tip - Drink 16 ounces of water one hour before exercise, 8 ounces 15 minutes prior, and 4 ounces every 15-20 minutes during exercise.

  3. Wild Blood Sugar Swings
    Many factors can cause blood sugars to swing from very high to very low.
    Tip - Know how long and how hard you are going to exercise, current insulin levels, how many carbs you need for your activity, whether to decrease insulin, increase carbs, or a combination of both. Adjust your carbs and/or insulin accordingly with your healthcare team's approval.

  4. Eating and Insulin Dosing too Close to Exercise
    A normal meal bolus (shots or pumps) may need to be lowered by 50% or more before exercise.
    Tip - As an example a person who takes 1 unit of insulin for 10 grams of carbs may take 1 unit for 20 grams of carbs prior to exercise. This must be discussed with your healthcare team prior to implementing.

  5. Eating the Wrong Carbs Prior to Exercise
    Not all carbs are alike. Different carbs are absorbed at different rates.
    Tip - Know the carbs and different rates of absorption. Fast acting carbs (e.g., Gatorade, fresh fruit) are great for raising low blood sugars before, during, or after exercise. Slower acting carbs (e.g., pasta, Power Bars) help avoid low blood sugars during long periods of exercise. They can be eaten about 1 1/2 hours prior to exercise and every 45 minutes to an hour during long periods of exercise.

  6. Low Blood Sugars During Exercise
    Aerobic exercise (running, swimming, biking, etc.) can cause your blood sugar to drop to unsafe levels.
    Tip - Test blood sugars often before, during, as well as 24-36 hours after exercise. If there is a pattern of low blood sugars, test 1 hour and a 1/2 hour prior to exercise to compare two numbers and this will give you enough time to make adjustments.

  7. Low Blood Sugar After Exercise
    When the body uses the fuel (mostly carbs) from the food we eat it turns to the liver and muscles for energy (glycogen or the stored form of glucose). If these stores are not replaced it is likely a person with diabetes will have a low blood sugar within 24-36 hours post exercise. This is called a lag effect.
    Tip - Make sure to snack after exercise (as long as blood sugars are in a good range) and possibly decrease basal insulin (shots or a pump) over the next 24 hours with your healthcare team's approval.

  8. High Blood Sugars Prior to Exercise
    The excitement of a competitive event can cause the blood sugars to spike due to hormonal activity in the body.
    Tip - Drink plenty of fluids and discuss with your healthcare team about reducing your correction bolus (shot or pump) by 50% before or during longer periods of exercise.

  9. High Blood Sugar During Exercise
    Anaerobic or strenuous exercise (e.g. sprinting, weight lifting) can raise the blood sugar if glucose is activated faster than it can be moved into the cells by the existing insulin on board.
    Tip - Drink plenty of fluids and work with your healthcare team to adjust insulin levels up using 50% less than your normal correction factor.

  10. High Blood Sugars Several Hours after Exercise
    Depending on the amount of insulin on board blood sugars may increase after exercise due to withholding too much insulin. Tip - Do not lower your total daily dose of insulin more than 50% due to exercise and drink plenty of fluids.

Rick Philbin, MBA, M.Ed., ATC

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