Waking up wired at 3am, or groggy no matter how much you sleep?
Your cortisol, sometimes known as the body’s stress hormone, could be behind it. And it’s not just about having too much.
To mark Stress Awareness Month (April), sleep expert Martin Seeley, CEO of MattressNextDay, has shared the ways in which too little or too much cortisol can silently sabotage your sleep in very different ways. He’s then provided tips for overcoming each of the outcomes, too.
What is cortisol, and why does it matter for sleep?
Cortisol is your body’s main stress hormone, released by the adrenal glands. It follows a natural 24-hour cycle, designed to wake you up in the morning and wind you down at night.
“It’s a common misconception that cortisol is always ‘bad’,” says Martin. “We need cortisol — but in the right amounts, at the right times. It’s meant to help you feel alert early in the day, and gradually drop so you can relax and fall asleep at night.”
Unfortunately, stress, burnout, poor sleep hygiene or blood sugar issues can throw this delicate balance off. That’s when problems begin.
“When cortisol is too high, it keeps you wired when your body should be resting. But too little cortisol can leave you flatlined and exhausted, even if you’re in bed for nine hours,” Martin explains.
Cortisol check-in: Do you have an imbalance?
Here’s how to spot whether your sleep issues could be down to high cortisol (“Wired & Tired”) or low cortisol (“Flatlined & Foggy”):
High Cortisol (“Wired & Tired”)
- You feel alert but exhausted at night, like your brain won’t switch off
- You wake up suddenly between 2–4am and struggle to get back to sleep
- You grind your teeth, clench your jaw or wake up tense
- You rely on coffee or energy drinks to power through
- You feel stressed even when there’s nothing urgent going on
- You find it hard to relax, even when your body is physically tired
“This is typical of a cortisol spike at the wrong time of night,” says Martin. “People think it’s anxiety or insomnia, but it’s often hormonal.”
Low Cortisol (“Flatlined & Foggy”)
- You wake up feeling exhausted, even after 8+ hours of sleep
- You feel dizzy when standing up too quickly
- You crash in the afternoon and rely on naps or sugar to stay awake
- You wake with vivid dreams and feel groggy or out of it
- You feel emotionally flat or lack motivation in the evening
- You feel like you’re always running on empty
“Low cortisol can look a lot like burnout,” says Martin. “It’s more common in people who’ve been under chronic stress, especially if they’ve ignored the signs for too long.”
How to rebalance your cortisol for better sleep
Martin shares his tailored advice depending on whether your cortisol is too high or too low.
If Your Cortisol Is Too High (“Wired & Tired”)
“Your aim is to calm your nervous system and reduce stimulation — especially in the hours before bed,” says Martin.
- Ditch intense evening workouts – “HIIT and spin classes after 7pm can ramp up cortisol when your body should be winding down,” Martin says. Opt for stretching, yin yoga or walking instead.
- Avoid doomscrolling – The blue light and emotional stimulation from social media can raise cortisol and make your brain feel ‘on’. Switch to a book, podcast or even audio journaling before bed.
- Keep evenings calm and dim – “Your environment sends cues to your brain,” Martin explains. Use warm lighting, lower your volume levels, and avoid heated arguments or work-related chats.
- Take a warm bath with Epsom salts – “Magnesium helps muscles relax and supports melatonin production,” says Martin. Aim for 20 minutes with dim lighting.
- Try 4-7-8 breathing – “It’s a powerful, free tool to activate your parasympathetic nervous system, otherwise known as the body’s ‘rest’ mode,” says Martin.
- Support your blood sugar – Eat a small snack like a banana with almond butter or Greek yoghurt to prevent dips that can cause a 2am cortisol surge.
If Your Cortisol Is Too Low (“Flatlined & Foggy”)
“The goal is to gently wake your system up and reinforce a healthy, energising rhythm, without overloading your body,” says Martin.
- Get 5–10 minutes of morning sunlight within 30 minutes of waking – “Natural light is the single best way to signal to your body that it’s time to be alert,” says Martin.
- Eat a protein-rich breakfast within an hour – “Skipping breakfast or starting your day with sugar alone can make cortisol drop even lower,” Martin warns.
- Move gently but regularly – Even if it’s just light walking or standing up for 5 minutes each hour, it helps regulate energy and mood.
- Try energising scents in the morning – “Peppermint or citrus oils can provide a natural lift,” says Martin. Use a diffuser or roll-on while getting ready.
- Use a ‘daylight’ alarm clock – “If you wake feeling like a zombie, a sunrise alarm can help gently nudge cortisol levels back into a healthy rhythm,” Martin explains.
- Focus on regular eating – Martin says to avoid long gaps between meals and pair carbs with protein and fat to support blood sugar, which in turn supports cortisol.
A final word
Martin adds: “It’s important to say that cortisol imbalance isn’t always caused by stress alone. If you’ve been struggling for weeks or months with poor sleep and low energy, it’s worth speaking to your GP to rule out other issues like thyroid problems, anxiety or nutritional deficiencies.”
