Why does my fasting blood sugar increase one to two hours after awakening? When I get up at 5:30 a.m., my blood sugar is 100 to 110 mg/dl [5.6 to 6.1 mmol/L]. If I don’t eat and recheck my blood sugar at 7:30 a.m., it will jump up to 150 to 200 mg/dl [8.3 to 11.1 mmol/L]. Why?

Blood sugars do not necessarily remain stable if you do not eat anything. They are affected by exercise, stress, illness, among others. If you are exercising in the early morning, before eating breakfast, this mild to moderate rise might be the result of the “stress of exercise.” In other words, when you exercise, your pulse goes up, your blood pressure goes up, and some of the hormones that antagonize insulin go up. This is not to say the effect is detrimental, because when you stop, the glucose levels go down. Also, at night, your body begins to produce hormones that antagonize insulin’s effects. Blood sugars may rise due to insulin resistance in the early morning.

JTL