Can't Sleep Through the Night? 7 Hidden Causes (And the Fix for Each)

Falling asleep is easy. Staying asleep is the problem. You're out cold by 11pm, and then like clockwork — 2:17am, 3:04am, 4:11am — your eyes pop open and you're awake for an hour staring at the ceiling.

This isn't insomnia, and it isn't "just getting older." It's almost always one of seven specific things. Here they are, with the fix for each.

1. Low electrolytes

The single most common cause for low-carb, keto and carnivore eaters. When sodium, potassium and magnesium are low, your nervous system can't dampen the small adrenaline pulses that happen overnight. Every one of them wakes you up.

The fix: 2,000–5,000 mg of sodium across the day, lite salt on one meal for potassium, and 300–400 mg of magnesium glycinate 30 minutes before bed. Most people see results by night two.

2. Late alcohol

One drink with dinner is fine for many people. But anything within four hours of bed reliably crushes deep sleep and triggers a 3am cortisol spike. Alcohol blocks REM, and as it wears off your body rebounds with adrenaline.

The fix: finish your last drink at least four hours before bed. If that's not possible, cut the volume in half and drink a full glass of salty water before you sleep.

3. Caffeine you forgot about

Caffeine has a half-life of about six hours. A 3pm coffee is still meaningfully active in your system at 9pm. For slow metabolizers (about a third of people) it's still active at midnight.

The fix: last caffeine of any kind — coffee, tea, dark chocolate, pre-workout — by noon for a week. See if it changes anything.

4. A bedroom that's too warm

Your core temperature has to drop about 1°F for deep sleep. If your room is above 68°F, your body fights against it all night and you cycle through light sleep instead.

The fix: 65–68°F. A fan, an open window, or a cooler mattress topper — whichever gets you there.

5. A blood sugar dip

If you eat dinner at 6pm and you're a fast metabolizer, your blood sugar can dip around 2–3am. Your body releases adrenaline to bring it back up, and that's what wakes you.

The fix: a small protein-and-fat snack within two hours of bed. A spoon of almond butter, a hard-boiled egg, a piece of cheese. Nothing carb-heavy.

6. Late screens

Blue-light filters help a little, but the bigger issue with phones at night is that they're emotionally stimulating. Doomscrolling, news, social media — those activate the same alert system as a real threat would.

The fix: phone out of the bedroom, or at minimum no scrolling apps for the 60 minutes before bed. A paper book or a podcast is fine.

7. Unprocessed worry

If you don't give your brain time to process the day, it'll do it at 3am whether you want it to or not. This is especially true for people running their own business or managing complicated lives.

The fix: ten minutes of "brain dump" journaling before bed. Everything on your mind, tomorrow's list, what's bothering you. Doesn't have to be tidy. Just out of your head and onto paper.

How to actually fix it

Work through these in order. Most low-carb eaters find the electrolyte fix alone solves it by night three. If it doesn't, you're probably hitting one of items 2–7 on top of it. Knock them out one a week and within a month sleeping through the night becomes the default again.

The bottom line

"Can't sleep through the night" is almost never a sleep problem. It's a physical signal — usually minerals, sometimes blood sugar, occasionally worry — with a specific, fixable cause. Identify which one is yours, fix it, and most nights look very different very quickly.