I swim laps for exercise and have been having some really bad hypos either during or just after swimming despite lowering both basal and bolus insulins. Is there something I can do or eat or drink before or during a swim that will help to maintain my blood sugar while I am in the pool, and prevent the hypos afterward?

Amy Campbell


My first suggestion is to work with your healthcare provider or a diabetes educator and continue to adjust your insulin doses, as it would appear that you are getting too much insulin, based on the amount of exercise that you’re doing. Depending on the intensity and duration of your swimming, you may need to decrease your insulin by 50 percent or more. In some instances, if you are swimming after a meal, you may not even need to take a pre-meal bolus dose. If you choose to eat a snack beforehand to prevent low blood glucose, the rule of thumb is to aim for 15 to 30 grams of carbohydrate for every 30 to 60 minutes of activity that you do. Energy and granola bars work well for people, as does fruit or yogurt. It may take a while to find out what’s best for you in terms of insulin adjustments and snacks; checking your blood glucose before, during and after your swimming sessions will make it easier to develop a regimen that works best for you and that will minimize low blood glucose.

March 8, 2013 at 3:11 pm

1 reply

Edie 2013-04-21 09:55:25 -0500 Report

Thankyou for this question, sometimes my sugar drops when I walk over 3 miles at once I will carry fruit juice and have my pickle bologna and crackers when I get back instead of before I go for that long walk. I don't take insulin but changing the way I snack before exercise may help to stop the drop as pickle bologna brings my BG down in the morning when I have it before bed at night.