Factors Affecting Blood Glucose
A variety of factors will affect how much of an effect exercise will have on your blood glucose. It is an individualized effect based on how long the workout lasts, how hard you exercise, what your glucose level was before the workout, what your insulin level was before the workout, your degree of insulin resistance, how well your body is hydrated or dehydrated and your metabolism.
When Glucose Increases
When you exercise, your body responds to the activity by releasing hormones that cause your body to increase blood glucose levels. This occurs through a process called gluconeogenesis or glycogenesis that happens in the liver. Glucose that has been previously converted and stored in the liver as glycogen is converted back to glucose and sent to the muscles. In the muscles, the glucose is broken down to yield ATP, which is the fuel source for muscles.
When Glucose Decreases
You body will continue to increase your blood glucose levels as its primary fuel source during your workout. However, once your body uses up its glucose, your blood glucose levels will drop. Instead, your body begins to draw on stored fat to fuel the workout.
To get the maximum effect on your blood glucose levels, you should be doing aerobic exercise. Running, jogging, stair steppers, swimming and other aerobic exercises increase your blood flow and the oxygenation of your tissues. These exercises demand more energy and that energy comes from your blood glucose. Following your workout, your blood glucose level remains low as the body rebuilds its glucose reserves in the liver.
Exercise with Diabetics
Though exercise is a great tool for diabetics, diabetics need to be careful about exercising. If you are involved in a long, hard exercise session (like a sports game), you may want to have a snack in the middle of your exercise session to keep your blood glucose levels from getting too low. Some regularly active diabetics have even been able to lower their insulin doses because exercise help them manage their glucose levels, according to Johns Hopkins Medicine. Diabetics should time their workouts within three hours of meals to help prevent your blood glucose levels from going too low. Also avoid exercising before bed so you don't experiencing problems from low blood sugar while you are sleeping.