Exercise & Blood Sugar
Exercise is more than going to the gym or playing a sport. Most activity is exercise. Activities of daily life—from cleaning, to gardening or shopping - are all forms of exertion that increase insulin sensitivity and that can lower your blood sugar. Most activity will lower the blood sugar, but not all.
Exercises that decrease blood sugar
Here are examples of exercise that will decrease the blood sugar:
Daily life activities, like shopping, cleaning, gardening, walking and sexual intimacy, as well as obvious sports activities, such as swimming, jogging and tennis, will increase insulin sensitivity and lower insulin requirements. These activities may require reducing the dose of insulin, and may require consumption of extra carbohydrate (PDF) to keep the blood glucose stable.
Exercises that increase blood sugar
Here are examples of exercise that will increase the blood sugar:
There are also activities and exercise that may increase the blood sugar. This is because the activity releases glucose counter-regulatory hormones, such as epinephrine (adrenaline) that opposes the action of insulin and raises the blood sugar. A classic example of this is bench-pressing free weights. It’s difficult to generalize, though, since other anaerobic activities will still lower blood sugar. Consult your medical provider team for specific questions regarding your activity.
In another example, competitive activities will often raise the blood sugar. Someone about to run a race gets an epinephrine (adrenaline) surge that is part of the competitive drive, which may result in an elevated blood sugar during the race. In contrast, the blood sugar can drop during practice.
Note: While it is important to understand why the same activity may give opposite blood glucose responses, the effect of stress on the blood glucose is not predictable, and we usually do not recommend increasing the dose of insulin in anticipation of stressful situations.