It is 11 p.m. You’re in bed. But your mind is still elsewhere.
That email you still need to answer. That conversation from this afternoon. That to-do list for tomorrow. It just keeps going.
You think you just have a busy mind, but at that moment something is happening in your body that goes far beyond thoughts alone.
You produce cortisol, and that is the last thing your body needs when it wants to recover.
What cortisol is
Cortisol is your stress hormone. It isn’t bad; you need it. Every morning, cortisol helps you wake up, feel sharp, and have the energy to take on the day.
But cortisol belongs to the day. Not to the night.
In the evening and at night, cortisol should be low. As low as possible. Because only when cortisol drops can your body switch to recovery. Repair muscles. Renew cells. Get the immune system to work.
Cortisol and recovery do not go together. It’s one or the other.
What stress does before sleep, in practical terms
If you’re stressed before bed, your cortisol level stays high. Your nervous system remains in a light state of alertness. Your body thinks something still needs to happen.
That has direct consequences. You sleep less deeply. Your REM sleep gets shorter. You wake up more often without noticing, and your growth hormone, the hormone that repairs your muscles and keeps your resistance strong, doesn’t get the space to do its job.
Your body can’t be on the brake and the gas at the same time. Stress is gas. Sleep is brake. As long as cortisol is high, the gas wins.
Why you feel this the next morning
You wake up and you’re already tired. Not because you slept too little, but because your sleep didn’t do what it was supposed to do.
Your head feels foggy. Your body feels heavy. You grab your phone and hope coffee will fix it.
That’s no coincidence. That’s what happens when cortisol has stayed too high all night.
What you can do
The solution isn’t sleeping more. It’s going into the evening differently.
Your body needs a transition period between the busyness of the day and the rest of the night. At least an hour. Preferably longer.
No more work after a certain time. No checking your email one last time. No finishing that one task just a bit longer. Your brain interprets that as: the day isn’t over yet. Cortisol stays high.
Write down your thoughts. Worrying before bed keeps cortisol active. A simple to-do list for tomorrow, on paper, gives your brain the signal that it can let go. You don’t need to remember it anymore.
Dim your lights. Bright light keeps cortisol high. Warm, soft light helps your body make the transition to night.
Breathe slowly. Long, calm exhales activate your parasympathetic nervous system, the part of your nervous system that lowers cortisol and starts recovery. Breathe in for four counts, breathe out for six. Five minutes. That’s all you need.
The habit for this week
Pick a time. Let’s say 9 p.m. From that moment on, no more work. No email, no to-do lists, no conversations about tomorrow.
Not because you’re lazy, but because your body needs that time to let cortisol drop before you go to bed.
Seven days. See what changes.
1% Better Every Night.
Guy Veeke
PS. A calm nervous system before sleep helps. But if you then still breathe through your mouth, your body stays unconsciously active all night. Nasal breathing lowers your heart rate, calms your nervous system, and helps your body truly let go. Mouth tape makes that easier.
