Answered 7/2/2015 by Samuel Grossman, BS Pharm, Pharm.D, CDE
Swimming is not contradicted when you inject insulin. However, when you inject the arm or the thigh, you may increase absorption of insulin from the site of injection when you swim, which may lead to low blood sugar levels. I recommend injecting into the stomach if possible. However, if you commonly inject in the thigh or upper part of the arm, I would recommend to wait 15-30 minutes after you inject pre-meal rapid-acting insulin to prevent potential low blood sugar levels when you go swimming.