How can exercise cause high blood glucose levels?

It seems strange when we know that the muscles are using glucose for exercise, but in type 1 exercising in certain situations can also cause blood glucose levels to rise. The reason for this is that insulin is needed to get glucose into the muscles. If there isn’t enough insulin around, glucose will stay in the bloodstream rather than get into the muscle, and the low insulin levels and muscle’s lack of glucose will stimulate the liver to product more glucose. This will ‘top up’ the bloodstream, but the muscles still cannot use this glucose as insulin levels are low. If exercise continues when there is little insulin around, blood glucose levels will continue to rise. This is the reason it is generally recommended that people with type 1 don’t exercise if blood glucose levels are high (above about 15mmol/L), particularly when ketones are present, as this signals a lack of insulin. on injections, early morning before breakfast may be a time where insulin levels are lower and blood glucose levels may increase with exercise. If this is a problem and you want to exercise at this time, some people find taking a small dose of insulin with a small snack before exercising does the trick.

❱ Avoid exercise when your blood glucose levels are greater than 15mmol/L and you have ketones in your blood or urine as this is a sign that you don’t have enough insulin around. In this case it is important to give some extra insulin to lower BGLs and eliminate ketones before starting to exercise. exercise session can reduce the risk of hypos for up to 2 hours after exercise. This seems to be due to the release of certain hormones with high intensity exercise, which cause the liver to release glucose and prevent the muscles from taking up as much glucose.

Another research group from Canada has discovered that the type of exercise (resistance versus aerobic) and the order may also make a difference. They found that resistance training (such as lifting weights) doesn’t lower blood glucose levels as much during the exercise session, compared to aerobic exercise, like walking, running or swimming. Resistance training also results in more stable and prolonged reductions in blood glucose levels after exercise. When they combined aerobic and resistance training in the one session, they found that doing resistance training before aerobic exercise resulted in more stable blood glucose levels throughout the exercise session and reduced the risk of postexercise hypos.

While these studies are only small and involve healthy, active individuals with type 1 diabetes, their findings might be useful to consider when trying to work out the effects of different types of exercise on your blood glucose levels.