Why do I wake up at 3 a.m. every night?

Common causes include alcohol (which fragments the second half of the night), blood sugar swings, sleep apnoea, stress-related cortisol rise, needing to urinate, and a too-early bedtime relative to sleep need. Persistent early-morning waking is also a classic depression symptom.

Brief awakenings between sleep cycles are normal; the issue is noticing them and then staying awake. Clock-watching reinforces the pattern by adding anxiety.

Alcohol is a common culprit — it shortens sleep onset but fragments the second half of the night as it is metabolised.