From the Guidelines
Nighttime blood sugar drops are called nocturnal hypoglycemia, a condition that occurs when blood glucose levels fall below 70 mg/dL during sleep, and it's particularly common in people with diabetes who take insulin or certain diabetes medications 1. This condition is characterized by symptoms such as night sweats, nightmares, restless sleep, morning headaches, and waking up feeling tired or confused.
Causes and Prevention
Nocturnal hypoglycemia may be due to impaired counter-regulatory response to hypoglycemia during sleep, and it can be asymptomatic 1. To prevent nocturnal hypoglycemia, patients should check blood sugar levels before bed and aim for a reading above 100 mg/dL, have a small bedtime snack containing carbohydrates and protein if levels are below 100 mg/dL, and consider adjusting medication timing or dosage under medical supervision.
Medications and Risks
Common medications that can cause nocturnal hypoglycemia include insulin (particularly long-acting types like glargine or detemir), sulfonylureas (like glipizide or glyburide), and meglitinides. This condition is dangerous because many people sleep through the warning symptoms, potentially leading to severe hypoglycemia. The body typically responds to falling blood sugar by releasing hormones like glucagon and adrenaline, but this response can be blunted during sleep or in those with longstanding diabetes 1.
Monitoring and Treatment
Bedtime testing is especially important because nocturnal symptoms may go unnoticed, causing severe hypoglycemia 1. If a patient’s blood glucose level drops below 100 mg per dL, he or she should eat a small snack. Continuous glucose monitoring systems can detect the frequency and severity of unrecognized hypoglycemic episodes; these systems are effective but expensive 1.
Key Recommendations
- Check blood sugar levels before bed and aim for a reading above 100 mg/dL
- Have a small bedtime snack containing carbohydrates and protein if levels are below 100 mg/dL
- Consider adjusting medication timing or dosage under medical supervision
- Use continuous glucose monitoring systems to detect unrecognized hypoglycemic episodes, if available and recommended by a healthcare provider 1.
From the Research
Definition of Nocturnal Hypoglycemia
- Nocturnal hypoglycemia refers to the condition where blood sugar levels drop at night, typically during sleep 2, 3, 4, 5, 6.
- This condition is common in patients with type 1 diabetes and can be asymptomatic, making it difficult to detect without regular blood glucose monitoring 2.
Causes and Risk Factors
- Nocturnal hypoglycemia can be caused by various factors, including:
- Insulin therapy, particularly nocturnal hyperinsulinemia 2.
- Exercise intensity, especially medium to high-intensity exercise during the day 3.
- Bedtime blood glucose levels, with lower levels increasing the risk of nocturnal hypoglycemia 3.
- Antecedent daytime hypoglycemia, which can increase the risk of nocturnal hypoglycemia 3.
- Age, with younger individuals being more prone to nocturnal hypoglycemia 3.
- HbA1c levels, with lower levels increasing the risk of nocturnal hypoglycemia 3.
Prevention and Management
- Various strategies can be used to prevent or minimize the frequency of nocturnal hypoglycemia, including:
- Regular blood glucose monitoring, particularly at bedtime 2.
- Ingestion of appropriate bedtime snacks 2.
- Utilization of short- and long-acting insulin analogues 2.
- Continuous glucose monitoring (CGM) with alarms and trend arrows to detect and prevent nocturnal hypoglycemia 4, 6.
- Automatic glucose adjustment (AID) systems with CGM and insulin pumps to regulate nocturnal glucose levels 4.