Aerobic exercise uses glucose as fuel, which reduces blood sugar during and after activity. Resistance training improves insulin sensitivity, meaning cells respond better to insulin over days and weeks. The blood sugar-lowering effect of exercise continues for up to 24 hours after a session.
People on insulin or sulphonylureas need to monitor blood glucose before and after exercise when starting a new programme because hypoglycaemia risk increases. Carry fast-acting glucose if you exercise outdoors or alone.