Nightime blood sugars

Dear Forum,

I was just diagnosed in early April and have been managing blood sugars between 70-170 most of the time. My average is 109 on my monitor. I take about 10 units of insulin per day, exercise 5x a week and eat low carb (around 15g-20g carbs/meal) almost every day. Otherwise, I would most likely have to take mealtime insulin since I’ve seen my sugar go up drastically with high carb/sugar foods.

I sometimes exercise 2-3 hours before going to bed and I’m worried about slipping too low overnight. My trend so far is a drop of between 5 to 40 ul over night. My question is, how low is generally too low when going to sleep and how long should I wait after exercising before going to bed?

Thanks in advance and be well!


Hi Sara!

You are up late!

You must still be on your honeymoon phase of being diabetic. 10 units a day? no bolus for meals? 2-3 hours of exercise at night? WOW.

Eat well, take shots.

Exercising at night is not “good” as it keeeps you awake; beter to exercise in the morning.

To answer your question, you will need to know how your body responds to you methods, but I am sure over time this will change.



Exercise is one of the toughest variables. Different types of exercise affect blood sugar differently. You’ll notice changes doing the same workout on different days.

You don’t need to stay up a certain amount of time. Some people deal with evening exercise by eating a snack with 15g carb and a protein before bed. Since your body is making insulin and you’re eating low carb, I’d probably not go to bed with a blood sugar below 120 until you learn exactly how the exercise and insulin are affecting you overnight. That would give you a little cushion if it drops in the middle of the night. You might set your alarm for about 2am for a couple nights just to test your blood sugar to see what the level is. Then see what you are in the morning.

The low carb thing is cool and you have good company with Dr. Richard Berstein who wrote “Diabetes Solution” and other diabetes books. He’s had type 1 for 60+ years with no complications and advocates low carb eating to keep low blood sugars and avoid hypoglycemia since the less insulin you take the fewer dosing errors you make. He also believes that someone like you who is newly diagnosed and still has strong insulin productions may be able to keep much of their islet cells intact by eating low carb.

To learn more about exercise get Sheri Colberg’s “The Diabetic Athlete.” She’s a type 1 diabetic who’s an exercise physiologist. What I like about the book is she recommends how to adjust insulin and snack to accommodate specific types of exercise. It’s great.