How Does Cortisol Affect Sleep?

Long Story Short

• Cortisol, commonly known as the “stress hormone,” is a chemical made in the brain that plays a role in our stress response, metabolism, and immune system.
• Cortisol levels in the body peak when you wake up in the morning and decrease to their lowest point in the evening, playing a key role in the body’s sleep-wake cycle.
• The morning increase in cortisol levels, known as the cortisol awakening response, may contribute to feelings of anxiety in the morning after you wake up.
• When cortisol levels are higher than normal, either chronically or specifically at night, you may experience difficulty falling asleep, trouble staying asleep, light sleep, and waking up early.
• Most people can manage their cortisol levels through good self-care, including getting quality sleep, regular exercise, limiting stress, and fostering healthy social relationships.

Cortisol is an important hormone that has various functions in the body, including how you respond to stress, plus immune system and metabolism regulation. (1) This chemical affects sleep by working with your internal clock (peaking in the morning and dipping at bedtime) and keeping your sleep-wake cycle on track. (2) Below, we’ll tell you all about cortisol and sleep, plus what you can do to lower your levels for better rest.

Note: The content on Sleepopolis is meant to be informative in nature, but it shouldn’t be taken as medical advice, and it shouldn’t take the place of medical advice and supervision from a trained professional. If you feel you may be suffering from any sleep disorder or medical condition, please see your healthcare provider immediately.

What Is Cortisol? 

Cortisol is often called a “stress hormone” because of its role in your body’s stress response, but it also helps other areas function, like your immune system, metabolism, and blood sugar levels. (1) It’s produced by your adrenal glands -– two small organs that each sit on top of a kidney.

The cortisol released from these glands attaches to receptors throughout your body and can affect all kinds of systems, including your nerves, heart, lungs, bones, skin, and reproductive organs — that’s how it can also help your body lower inflammation and control blood pressure. (3) As such an important hormone, cortisol needs to follow certain rules on its release timing and amount.

“Balanced cortisol levels are important — if the levels get too high or too low, it can lead to health issues,” says Raj Dasgupta, Sleepopolis’ chief medical advisor. And one of those health issues is getting enough good quality sleep.

Cortisol, Sleep, and the Circadian Rhythm 

Throughout the day and night, three important organs (the hypothalamus, pituitary gland, and adrenal gland) communicate to decide how much cortisol to release and when. This trio is called the hypothalamus-pituitary-adrenal (HPA) axis. (1) The HPA axis has a big say in your stress management and creates a loop of messages to constantly gauge your stress and fine-tune the chemicals they release in response.

Here’s the kicker: the HPA axis follows a circadian rhythm (the internal clock that helps you know when it’s time to sleep or wake up). So, although stress and other factors can prompt cortisol release, your cortisol levels also rise and fall on a schedule: high in the morning and low at night. (1) (3) And when your cortisol levels stay too high, your sleep-wake cycle can easily get confused. (4)

Cortisol also works closely with melatonin, a hormone that fluctuates throughout the course of the day and helps you feel sleepy before bed. (5) Melatonin affects your internal clock, and, like cortisol itself, your circadian rhythm plays a huge role in several areas, like behavioral patterns (mood), sleep-wake cycles, and metabolism. Both cortisol and melatonin also help your brain regulate its 24-hour circadian cycle. (6)

If you see a lot of overlap here, you’re reading the room right. All these hormones and processes work together in an intricate dance that affects your sleep.

Normal Cortisol Levels and Their Impact on Sleep

For optimal sleep health, your cortisol levels should peak in the morning, and dip in the late afternoon. For example, from around 6 a.m. to 8 a.m., normal cortisol levels stay between 10 and 20 micrograms per deciliter (mcg/dL). Around 4 p.m., they should be lower: between 3 and 10 mcg/dL. (3)

But how do you know your numbers? “Your cortisol levels can be assessed through blood, saliva, or urine tests if deemed necessary by your physician or endocrinologist,” Dasgupta tells Sleepopolis. Once you know your levels, you can develop a plan with your healthcare provider to nudge them back into balance if needed. 

If you don’t, too-low or too-high cortisol levels can make it harder to fall asleep, stay asleep, and wake up feeling rested. (5)

How High Cortisol Levels Disrupt Sleep 

If your cortisol levels stay high when you’re lying in bed at night, you may find it hard to nod off. High cortisol levels can also affect your circadian rhythm as a whole, adding to sleep troubles. (2) (4) 

“Signs of chronically elevated cortisol level can include…poor quality and quantity of sleep,” Dasgupta tells Sleepopolis. Left too long, high cortisol can contribute to insomnia and even cause morning anxiety. (3) (7) 

Cortisol and Insomnia

Stress — a well-known sleep disruptor — can boost cortisol, and chronically high cortisol can even lead to chronic insomnia, which means you have trouble sleeping at least three nights per week for over three months. (3) (4) Elevated cortisol levels can also wake you up before you want to, leading to less overall sleep. (8)

What’s more, when you miss out on enough sleep, that itself can increase your late afternoon cortisol, further throwing your circadian rhythm out of whack. (2) Fun, right? (Stick with us — we have some solutions coming up!)

Cortisol doesn’t necessarily have to spike before bed to disrupt your sleep — chronic high cortisol can mess with deep sleep and wake you up frequently through the night. (9) But pre-bed cortisol spikes definitely don’t help either. If you go to bed stressed with adrenaline and cortisol pumping through your veins, you’re more likely to stay on high alert and have trouble sleeping. (3)

Cortisol and Morning Anxiety

For those with chronic stress, cortisol levels are higher in the first hour after they wake up, which can prompt morning anxiety. (7) This cortisol spike, often called the “cortisol awakening response,” happens independently of other spikes and doesn’t seem to affect the circadian rhythm. (2) 

Below, we’ll let you know what you can do to prevent this spike, lessen your morning anxiety, and get better sleep overall.

Factors That Influence Cortisol Levels 

All kinds of factors can influence your cortisol levels and impact if you experience spikes or high cortisol throughout the day. The most well-known trigger for higher cortisol levels is stress, but it’s certainly not the only trigger. “Stress triggers the release of cortisol, but other factors like your circadian rhythm, sleep quality and quantity, exercise, and overall health also affect its production,” Dasgupta tells Sleepopolis. 

Environmental factors that can boost your cortisol include things like skimping on daily exercise, feeling stressed often, neglecting hobbies and things that make you happy, and living with tense, unhealthy relationships. (3)

Nutrition and light exposure can also play a role in cortisol levels. For example, diets high in inflammatory foods may lead to a damaging boost in cortisol production over time. (10) But bright morning light can boost cortisol at the right time (when you wake up), helping you perk up for the day. (11)

Other times, the problem comes from within, and cortisol levels can get unbalanced because of illness or a chronic disease. For example, long-term low cortisol can originate from conditions like Addison’s disease, kidney infection, or problems with your pituitary gland, which makes several important hormones. (3)

On the flip side, high cortisol levels can arise from tumors of the pituitary gland, lung, and adrenal gland, and they can also be a side effect of large doses of steroid medications like prednisone, prednisolone, or dexamethasone. (3) But if you deal with high cortisol, you may be able to decrease those levels naturally, leading to better health and happier sleep.

How to Lower Cortisol Levels Naturally 

Stress happens, and you can’t always avoid a cortisol spike. But you can adopt a lifestyle of stress-fighting habits that help you keep a lid on your cortisol and maintain the right balance. “To address elevated cortisol levels, you can start journaling your stressors and stress management techniques (exercise, relaxation exercises, adequate sleep, dietary changes) and bring them to your doctor’s appointment,” Dasgupta tells Sleepopolis.

For overall balanced cortisol levels, you can incorporate these stress-busting techniques: (3) (8) (12) 

• Exercise most days — any little bit helps, but the more you can do, the better you’ll feel. (13)
• Use deep breathing exercises to calm down your stress response.
• Make time for your hobbies, which can boost feelings of well-being.
• Focus on healthy relationships and set boundaries in difficult ones.
• Lessen your intake of unhealthy products like caffeine, alcohol, cigarettes, mood-altering substances, and junk food.
• Try mindfulness techniques like meditation, guided imagery, and visualization.
• Do yoga exercises and stretches to connect your mind and body and melt away stress.

If these tips don’t seem to help enough, you can talk to a counselor about therapy, which helps many people change negative thought patterns and experience less stress. (3)

How to Prevent Cortisol Spikes at Night

If your cortisol tends to jump right as you hit the sheets, you can try a few things to prevent this. Incorporating all the tips above helps stop the spike, too, but you can also use good sleep hygiene to prevent a cortisol boost before bed. These habits include: (8) (14)

• Keep a regular sleep routine and schedule (even on the weekends).
• Stay hydrated throughout the day.
• Avoid intense exercise in the hours before bedtime.
• Make your sleep space cool, dark, quiet, and comfortable.
• Stick with light snacks before bed (as opposed to heavy meals).
• Try to steer clear of screens close to bedtime.

When you couple these sleep tips with the de-stressing techniques above, you may just set yourself up for more balanced cortisol levels and better sleep. If you feel nothing is helping, always feel free to loop in your provider. If you have anxiety surrounding sleep, they can connect you with a mental health professional to help you manage your symptoms.

FAQs

The Last Word From Sleepopolis

Cortisol, the “stress hormone,” regulates not just your stress response, but many other areas of your body and health, like your immune system and metabolism. High cortisol at the wrong time can disrupt your sleep, but you can protect your rest by adopting healthy habits like regular exercise, a nutritious diet, mindfulness techniques, and good sleep hygiene. If you think you may have a cortisol imbalance and feel unsure how to handle it, let your healthcare provider know and they can help you make a plan.

Sources

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7. Tips for Coping with Morning Anxiety | Wake Forest University. Accessed November 4, 2024. https://counseling.online.wfu.edu/blog/morning-anxiety-tips/
8. sleep and cortisol in PTSD – PTSD UK. Accessed November 4, 2024. https://www.ptsduk.org/sleep-and-cortisol-in-ptsd/
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12. Stress relievers: Tips to tame stress – Mayo Clinic. Accessed November 4, 2024. https://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress-relievers/art-20047257
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