Avoiding Lows During Activity

Once you are on insulin or a sulfonylurea, exercise can cause hypoglycemia — blood sugar falling too low. It is manageable with a routine, and the routine is short.

1. Check before you start. Below about 100 mg/dL, eat 15 to 20 grams of carbohydrate first — a small banana, a couple of biscuits, or a glass of juice.
2. Carry fast-acting glucose. Glucose tablets, a small pack of juice or a few toffees. Keep it on you, not in a bag left at the side.
3. Tell someone. A walking companion or gym staff should know what to do if you become confused or unwell.
4. Check afterwards, and again a few hours later if the session was long or unusually hard.

Know the symptoms so you act before it becomes serious: shakiness, sweating, a pounding heart, sudden hunger, irritability, confusion, or feeling weak and light-headed. Treat first and check afterwards if you are unsure.

Two situations deserve extra care. Exercising alone in an isolated place is riskier than exercising in company. And swimming carries a particular risk, because the early symptoms of a low are easy to miss in water.

If lows keep happening around exercise, your doses probably need adjusting rather than your exercise cutting.