From the Guidelines
Nocturnal hypoglycemia is a condition where blood sugar levels drop too low during sleep in people with diabetes, and it is crucial to prevent and manage it to avoid severe consequences, as evident from the study published in 2025 1. When sugar goes down at night with diabetes, it is called nocturnal hypoglycemia, a condition that can be asymptomatic and may be due to impaired counter-regulatory response to hypoglycemia during sleep, with a reported incidence of 14 – 47% 1.
Causes and Symptoms
Some common causes of nocturnal hypoglycemia include:
- Taking too much insulin or diabetes medication before bed
- Insufficient evening food intake
- Alcohol consumption
- Increased physical activity during the day Symptoms may include:
- Night sweats
- Nightmares
- Morning headaches
- Restless sleep
- Waking up with a rapid heartbeat
Prevention and Treatment
To prevent nocturnal hypoglycemia, patients should:
- Check blood sugar before bed and aim for levels above 100 mg/dL
- Have a small bedtime snack containing carbohydrates and protein if blood sugar is below 120 mg/dL
- Avoid alcohol close to bedtime
- Consider using continuous glucose monitors with alarms Treatment involves consuming 15 grams of fast-acting carbohydrates like glucose tablets or juice, waiting 15 minutes, and rechecking blood sugar 1.
Insulin Therapy Adjustments
For those on insulin therapy, discussing dosage adjustments with healthcare providers is essential, as they may recommend reducing evening insulin doses or changing the timing of long-acting insulin administration to better match individual needs and activity patterns, and using longer-acting basal analogs (U-300 glargine or degludec) can convey a lower nocturnal hypoglycemia risk than U-100 glargine 1.
Key Recommendations
The most critical step in managing nocturnal hypoglycemia is to work with a healthcare provider to adjust insulin doses and timing, and to use technology such as continuous glucose monitors to detect and prevent low blood sugar levels, as recommended in the 2025 standards of care in diabetes 1.
From the Research
Definition and Overview of Nocturnal Hypoglycemia
- Nocturnal hypoglycemia refers to low blood sugar levels that occur at night, typically during sleep, in individuals with diabetes 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, 4.
Causes and Risk Factors
- Nocturnal hypoglycemia can be caused by various factors, including inappropriate basal insulin therapy, intensive insulin regimens, and the use of certain insulin analogues 2, 3, 6.
- External factors such as exercise, alcohol consumption, and hormonal influences can also contribute to the development of nocturnal hypoglycemia 5.
Effects and Consequences
- Nocturnal hypoglycemia can have severe consequences, including convulsions, coma, and even sudden death, known as the "dead-in-bed syndrome" 2.
- Recurrent exposure to nocturnal hypoglycemia can impair cognitive function and lead to the development of acquired hypoglycemia syndromes, such as impaired awareness of hypoglycemia 2.
- Nocturnal hypoglycemia can also have negative psychological and social effects on individuals with diabetes, affecting their overall well-being and quality of life 5.
Detection and Prevention
- Continuous glucose monitoring (CGM) has been shown to be effective in detecting and preventing nocturnal hypoglycemia, particularly when used in combination with insulin pumps and automatic glucose adjustment systems 4, 5.
- Regular blood glucose monitoring, bedtime snacks, and the use of short- and long-acting insulin analogues can also help minimize the risk of nocturnal hypoglycemia 2, 3.