In Liz’s case, her blood glucose normally rises about 150 points during a meet, and her usual insulin sensitivity is 25 points per unit. Instead of taking 6 units of insulin before the meet, she takes 3 units.
The same “half-the-usual-dose” rule applies to “correction” doses for high blood glucose levels immediately before or immediately after competitive or high-intensity events. Take half the usual “correction insulin” for high blood glucose levels in these situations.
If you are nervous about giving insulin before exercise, check your blood glucose level more often than usual (perhaps every half-hour or so), and have glucose tablets or some other form of carbohydrate nearby. With some experience, you will develop greater confidence and have the ability to fine-tune your pre-exercise doses.
Ever finish a workout with a terrific blood glucose level only to go low several hours later or overnight? Many aerobic activities (particularly those that are long or intense) and most anaerobic exercises cause blood glucose levels to drop several hours later. This phenomenon is called delayed-onset hypoglycemia. There are two reasons this occurs. One is the prolonged, enhanced sensitivity of muscle cells to insulin following activity. The other is the need for muscle cells to replenish their own energy stores following exhaustive exercise. Muscle cells store glucose in a storage form called glycogen.
Delayed-onset hypoglycemia is unique to each individual. The best way to deal with it is to keep records of when it happens (after what types of activities? how many hours later?) and then make adjustments to prevent it. For example, Liz tends to drop low in the middle of the night following her two-hour evening practices. To prevent this, she lowered her pump’s basal insulin delivery by 40% for eight hours following her practices. People who take injections can lower their intermediate- or long-acting insulin by 20% to 25% following intense exercise. Another option for people who take insulin or an oral medicine that can cause hypoglycemia is to have an extra snack before the time their blood glucose level tends to drop. Ideally, the snack should contain carbohydrate-containing foods with low glycemic index values (meaning they are digested relatively slowly). Examples include whole fruit, milk, yogurt, peanut butter, pasta, and chocolate. (Finally, a therapeutic application for chocolate!)
Think before you stink
Exercise and other daily activities are meant to be enjoyed. Managing your blood glucose levels effectively during and after physical activity will ensure that you feel good, stay safe, and perform your best. Hey, it even worked for Anthony. Not only is he walking after dinner without developing low blood glucose, he seems to actually enjoy it now. Just don’t tell his wife!