Glucose Management - ExCarbs


Before You Exercise

  • Check your blood sugar – if it is less than 90 mg/dl (5 mmol/l) you will need to take an extra carbs, at least 10-20g, and then re-check. Delay starting until blood sugar is above 90 mg/dl (5 mmol/l).
  • If blood sugar levels are between 90 to 120 mg/dl (5 and 6.7 mmol/l) take 10-20 g of carbs before starting aerobic activity. If you plan anaerobic exercise and high interval training you can start.
  • If blood sugar is 120-250 mg/dl (7-15 mmol/l) go ahead and start – these could rise with anaerobic exercise.
  • If you are above 250 mg/dl (14 mmol/l) and you have not recently eaten, check for ketones, correct with insulin if ketones are present and delay your exercise.

During Your Exercise

  • Set a targeted range to keep your blood sugar in (e.g. 100-250 mg/dl, 6-14 mmol/l).
  • Measure your blood sugar levels about every 30 minutes, or use GCM to make sure you are in your target range.
  • Take regular fluids (250 mls every 30 minutes) — water is best if your glucose is at or above target.
  • You may need extra carbs to maintain your sugar in target.
  • Having a sharp, short, full on sprint for 10 seconds at the end of moderate intensity exercise can prevent a post-exercise low. This works by causing the body to release large amounts of adrenaline which turns on the liver to release more glucose and slows down the uptake of glucose by your muscles – try it and see, especially if you have been doing aerobic exercise. 
  • Doing weight training before aerobic exercise also helps keep blood glucose levels from dropping too much.

After You Exercise

  • Measure your blood sugar for up to 2 hours after exercise and at the next meal to see if any adjustments in insulin are needed.
  • You may need a meal or snack (low Glycaemic Index preferably with some additional protein), taken with no or reduced bolus insulin to protect against a low later. You may also need to reduce the dose of long-acting basal (background) insulin or the basal rate on your pump, before bed or the evening of the same day you exercised.