Exercise & blood glucose

The blood glucose level will increase on account of exercise if there is not enough insulin.

The cells don′t “understand” that there is plenty of glucose in the bloodstream. On the contrary, they act as if the body was starving. This is caused by the muscle cells having a lack of glucose following a period of exercise in the presence of insulin deficiency. The muscle glycogen is used up, and insulin deficiency prevents new glucose from entering the cells. Hormonal signals will then tell the liver to release more glucose from its glycogen depot. The signals to the liver are communicated by the hormones glucagon and adrenaline. The increased amount of glucose in the blood comes from both a breakdown of the liver′s glycogen and a production of glucose in the liver.

At the same time, when there is a lack of insulin, there will be a breakdown of fat to fatty acids which are transformed into ketones in the liver. This puts you at risk of developing ketoacidosis. When your blood glucose level is above 14 mmol/l (250 mg/dl), and there are raised ketone levels indicating lack of insulin delivery, exercise should be postponed while extra insulin is taken. Running to lower a high blood glucose in this situation is not a good idea. It might even be dangerous.

Episodes of serious ketoacidosis, caused by missed insulin injections and requiring hospital treatment, are not uncommon. Many of these cases involve teenagers who do not realize how dangerous it can be to leave out insulin injections.