Type 1 Diabetes is affected by most things we do in life. Blood sugars can fluctuate due to a lot of things, and exercise is one that has a high effect on the fluctuations.
It is commonly known that blood sugars fall from exercising, but that is not exactly true. Different types of exercise will have a different effect on blood sugars.
The only type of exercise that lowers blood sugars directly is cardiovascular exercise. This is due to low stress hormone response and the breakdown of glucose via the aerobic energy system.
Resistance exercise actually rises blood sugars during training, and they start falling straight after, or a few hours after. This also holds true for most high intensity exercise. This is due to a high stress hormone release and the anaerobic energy system being used rather than the aerobic. The stress response will cause the live to release extra stored glucose, resulting in an overall blood sugar rise.
Some individuals may require extra bolus insulin to manage their resistance or high intensity exercise. This requires experimentation, and the amounts, timing and management will be personal to every individual.
These 2 videos are all about how to manage your blood sugars with exercise and avoid massive fluctuations.