Why should I check my blood sugar during exercise if I have diabetes?

Normally the body hums along, releasing the right amounts of insulin and adrenaline to keep the blood sugar level normal even with vigorous exercise. But if you have diabetes, you don't make adequate levels of insulin on your own, and you may not make adrenaline properly either, particularly if you have autonomic neuropathy, damage to the nerves that help regulate heart rate, blood pressure, and other internal organ functions. Too little adrenaline and/or too much insulin can plunge your blood sugar to hypoglycemic levels.

Over the long term, exercise almost always improves blood sugar levels. But during the short term, it can sometimes be hard to predict how your blood sugar level will react. The whole situation can get even a bit more complex when you are taking medicines designed to lower your blood sugar levels. That's why it's so important to monitor yourself carefully as you increase your exercise routine.