Final answer:
For a type I diabetic, markedly increased levels of insulin before exercise can lead to a significant decrease in blood glucose concentration during continuous aerobic exercise as insulin promotes the uptake of glucose by the body's cells.
Step-by-step explanation:
If insulin levels are markedly increased above normal when a type I diabetic begins exercise, continuous aerobic exercise would result in a significant decrease in blood glucose concentration. This happens because increased blood glucose levels stimulate insulin production, which in turn facilitates the uptake of glucose from the blood into the cells to be used as energy during the exercise. Therefore, if a Type I diabetic has administered an insulin injection before exercising, their cells are able to absorb glucose more efficiently, which decreases blood glucose levels (hypoglycemia). It's also important to note that in individuals with Type 1 diabetes, insulin must be administered because their pancreas does not produce enough insulin, if any. During exercise, as muscles consume glucose, it could further lower blood glucose levels, posing a risk of hypoglycemia if not monitored closely.
Without the action of insulin, as seen in insulin non-responsive diabetes mellitus patients, the blood glucose level would not decrease significantly upon insulin injection due to excessive insulin antagonists, defective insulin receptors on the cell membrane, or antibodies to insulin.
Subsequently, after a meal or when blood glucose levels rise, the beta cells of the pancreas normally release insulin to sequester excess glucose in the blood. This leads to storage of glucose as glycogen in the liver and a reduction in blood glucose levels. During exercise, if insulin has been administered, the effect of pushing glucose into the cells to be used or stored is even more pronounced, hence the likelihood of a significant decrease in blood glucose levels.
Blood Glucose Level During Exercise for Diabetics
For a Type I diabetic who takes insulin before exercise, the blood glucose level will likely fall, reflecting the function of insulin in enabling cellular uptake of glucose for energy, especially during the increased demand of continuous aerobic exercise. This can lead to hypoglycemia if blood sugar is not monitored properly.