Understanding Overnight Numbers

The overnight stretch is the longest period nobody is watching, and it is where a lot of Type 1 confusion comes from.

Low blood sugar during the night often does not wake you. Instead it shows up indirectly: nightmares, waking sweating, or feeling confused and unwell in the morning. If those are happening, the night is worth investigating rather than accepting.

A high morning reading is the more common puzzle, and it has more than one possible cause. Your background insulin may simply be too low to cover the night. Or your body may be producing glucose in the early hours as part of its normal waking-up process. Or — and this is the one people miss — you may have gone low overnight and your body pushed glucose back up in response, leaving you high by morning.

These need opposite responses. Increasing your night insulin will help the first and make the third considerably worse.

So do not adjust a bedtime dose based on morning readings alone. Check at bedtime, and if possible once during the night for a few nights, or use a sensor for a couple of weeks. Take the pattern to your doctor rather than guessing at it.