This lowers the level of insulin in the blood. Glucose is then released from the liver to top up the blood glucose level in order to keep it within the normal range. The critical point in this series of events is the decline in insulin production, which occurs in response to the exercise and drop in blood glucose. Low insulin levels encourage the liver to release glucose into the bloodstream. Low insulin levels also favour the breakdown of fats into fatty acids, providing the other source of fuel for exercising muscles.
Sufficient insulin is produced so that cells can access the glucose in the bloodstream.
So, exercise lowers the blood glucose level. This brings about a reduction in insulin secretion. Lower insulin levels favour the release of glucose and fatty acids. The blood glucose level is maintained and the exercising muscles are provided with plenty of fuel for energy. Let us look at what happens when you, someone with Type 1 diabetes, start exercising.