Editing Openai/69728cc0-fcfc-8004-b2b5-d3c1774ab8cc (section)

=== Assistant: Yeah, that’s super annoying 😭 And it’s also pretty common for sleep to “snap” after 4 hours because that’s roughly one… ===
Yeah, that’s super annoying 😭 And it’s also pretty common for sleep to “snap” after ~4 hours because that’s roughly one big chunk of sleep cycles, so a bunch of things can tip you into waking right there.

A few likely culprits (and how to sanity-check them):

Stress / cortisol spike (even if you don’t feel “stressed”)
Your brain can be calm-ish, but your body is like “lol no”. Cortisol tends to rise in the early morning, and if it’s running high (anxiety, life stuff, job stuff, deadlines, conflict, even excitement), you can wake up wired after 3–5 hours.

Alcohol or nicotine
Alcohol helps you fall asleep but often fragments sleep later in the night and increases early waking. Nicotine can do similar. Even “not that much” can be enough for some people.

Caffeine timing
Caffeine has a long half-life (often ~5–6 hours, sometimes longer). Afternoon coffee/energy drinks, or even tea/soda, can cause that “wake after 4 hours” pattern.

Eating pattern / blood sugar wobble
Big late meal, lots of sugar, or going to bed hungry can both trigger a 3–4 hour wake-up. Your body does a little glucose-management drama and boom, awake.

Temperature or environment changes
You mentioned you get hot easily. Overheating is a classic “wake after a few hours” trigger, especially once you’re deeper into sleep and your body’s trying to cool itself. Also: dry air, noise, light creeping in, or a partner/flatmate noise.

Sleep schedule drift
If you’ve been going to bed later, sleeping in, napping, or your bedtime is inconsistent, your circadian rhythm can basically go “cool, we’re doing a split sleep now”. Historically humans often slept in two chunks (“first sleep” and “second sleep”), so it’s not your body being broken, it’s your body being… annoyingly ancient.

Sleep apnoea / breathing issues (worth thinking about)
If you snore, wake up gasping, have morning headaches, dry mouth, or feel wrecked despite time in bed, apnoea jumps up the list. It can cause repeated awakenings and lighter sleep. Not a diagnosis, just a “flag to consider”.

Medication / supplements / withdrawal
Starting/stopping certain meds (including some anxiety/depression meds), decongestants, or even stopping something like cannabis can mess with sleep architecture for a bit.

===== What you can do tonight (simple, low-effort) =====
* If you wake up: don’t stay in bed fuming. Get up, dim light, do something boring (paper book, calm podcast), then back to bed when sleepy. This stops your brain from learning “bed = frustration arena”.
* Cool the sleep setup: lighter duvet, fan, cooler room, moisture-wicking clothes, cold water nearby.
* Cut caffeine earlier (try none after ~12–2 pm for a few days).
* Avoid alcohol close to bed (ideally skip for a few nights and see if it fixes it).
* Tiny snack if you suspect hunger/blood sugar (something boring like yoghurt, peanut butter toast, or a banana).

===== When it’s worth getting checked =====

If this keeps happening most nights for 2+ weeks, or you’ve got signs like snoring/gasping, chest pounding, severe anxiety on waking, or daytime sleepiness that’s sketchy (like nodding off), it’s worth a GP chat.

One quick thing that would narrow it down a lot: when you wake after 4 hours, what’s it like?
Are you wide awake and alert, or sleepy but can’t get back down? And do you wake hot, sweaty, anxious, needing to pee, or with your heart racing?