Night-Time Lows
Reviewed by CDE Mehandi Sharma · Updated
Overnight is the most dangerous stretch for low blood sugar, for one simple reason: you may sleep straight through it.
Because the usual warning signs arrive while you are unconscious, a night-time low often shows up only indirectly. The recognised signs are nightmares, waking sweating or with damp bedclothes, and feeling confused or unwell in the morning. A morning headache is common.
If any of those are happening more than occasionally, the night needs investigating rather than tolerating.
What to do about it. Check before bed every night rather than relying on your last reading from the evening — a bedtime number at the low end of your range is a reason to eat something, even feeling fine. Check during the night for a few nights if you suspect a pattern, or use a sensor with alarms, which is one of the strongest arguments for continuous monitoring in Type 1.
Pay particular attention after evening exercise or alcohol, both of which push the risk into the small hours.
And do not respond to a high morning reading by increasing your night insulin without checking overnight first — you may be seeing a rebound from a low you slept through, in which case more insulin makes it worse.