Avoiding Low Overnight Blood Sugars

What do you fear most about your diabetes? What literally keeps me up at night is the possibility of having a low blood sugar while asleep.  One night in high school, after an intense week of football, I woke up to a low blood sugar.  It was a long, hard fought week; I was resting after a close game against our rival program.  I was exhausted.  I must have been low for a while because upon awakening , I was very shaky.  I began to treat it as usual with  glass of orange juice, wait 15 minutes, and assess.  My blood sugar began to rise, but I was still shaky.    In the blink of an eye, I was in a hypoglycemic seizure.  Luckily my parents were awake and present to treat me with injectable glucagon, eventually raising my blood sugar level and ending my seizure.

What had happened that night? My blood sugar had clearly begun to rise, responding to my orange juice intervention, but then it quickly dropped again.

Today’s science lesson:  Your muscle cells store its own glucose for fuel. When you work out for an extended period of time without supplying them with constant fuel, the glucose stores are depleted.  Exercising on a consistent basis, your liver’s glucose reserves begin to run low as well.  After a long hard week of football, my reserves were depleted.  No matter the activity: hiking, swimming, football, etc,  between 2-48 hours after a workout, your muscles will try to replenish its glycogen stores, soaking up all the glucose they need from your circulating  blood . 

That’s crazy! How are you supposed to anticipate that?!

In an individual that produces their own insulin, their pancreas will temporarily shut down insulin production, allowing the liver to release it’s glycogen stores and keep your blood glucose levels at a level in which your brain can happily function at (no seizures).  A person with insulin dependent diabetes does not have the luxury of knowing when the replenishment will occur.

Another factor to consider depends on your normal activity level.  If you recently became more active, you are more prone to having such events even after only one day of physical activity.

What can you do as an athlete with diabetes to avoid this?
The unfortunate  truth is that there is no way to know when your muscles are going to decide to replenish its glycogen stores.   You can, however, develop a safety strategy. I have implemented the 20/20 rule:  20 grams of carbohydrate for every 20 minutes of exercise.  This will keep the glycogen in our muscle cells, a decrease the risk of the replenishing event that can get you in trouble as a person with type 1 diabetes.  A recovery meal consisting of the correct ratio of carbohydrates, protein and fat within 20 minutes of ending your exercise will help raise your glycogen levels in your muscle cells.  I also encourage you to check your sugar levels often when starting a new fitness regiment. This will help you learn how your body reacts to fitness, heightening your potential of performance.


No matter how careful we are the body can sometimes be unpredictable.  There are more lessons to present on avoiding such a situation and the safety steps you should always have in place for yourself/your child/spouse/roommate.

Please share stories of diabetes issues you have had and if you have found solutions in comments!