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How Cortisol is Messing with Your Sleep

You may have heard of the stress hormone cortisol.  This hormone driving the fight-or-flight response may be helpful for dodging scooters on the sidewalk, for example, but it’s not as useful when you’re trying to fall asleep — or feel ready for sleep.  

Cortisol, which plays a variety of roles in the body to mobilize energy and promote alertness, may be affecting your sleep patterns. Cortisol levels are lowest at night and when we are sleeping. That said, sleep deprivation is known to elevate cortisol levels.

If you’re wondering how to decrease your cortisol levels naturally to get better sleep then read on. Let’s take a look at how cortisol works, its effects in the body, and the relationship between cortisol levels and sleep.

What is cortisol?

Cortisol functions as a chemical alert system for your body, mobilizing energy resources to help you overcome perceived  threats. It’s produced by your body’s adrenal glands, which are situated atop the kidneys, and the stress hormone travels through the body via your bloodstream.

The stress hormone exerts effects on your brain (controlling mood, motivation, and fear), as well as on your metabolism (boosting energy to handle stressors). It also reduces inflammation and controls circadian rhythm processes such as the sleep-wake cycle, among other functions.  Cortisol’s role in the fight-or-flight response helps ensure that you are alert and that your body has energy to deal with stressors.[1]

When chronic stress increases your body’s cortisol release over an extended period of months or years, this stress hormone can start to cause serious problems.  Chronic exposure to elevated cortisol can cause a host of problems. These problems include both sleep problems and weight gain, which we will talk about below.  

Other serious effects of chronic exposure to elevated cortisol include anxiety, depression, problems with your digestive system, headaches, memory and concentration problems, and even heart disease.[2]

Cortisol levels and sleep

The natural levels of cortisol in the body are lowest at night, around midnight.  A couple of hours after you fall asleep, cortisol levels begin to rise and increase through early morning to promote an awakening response. Your body’s cortisol level peaks around 9am, and the levels decline as the day progresses.[3

The amount of cortisol in your bloodstream is typically at its lowest levels while you sleep.  Levels decrease from the time you fall asleep to about midnight, when cortisol levels are at their lowest.  

Some sleep disorders may also serve to boost cortisol levels at night, interfering with both sleep and one’s physiology.  For example, there is a link between sleep apnea and cortisol. People with sleep disorders such as sleep apnea may experience elevated cortisol levels at night, which can cause metabolic and cardiovascular stress.[4]

Chronically high cortisol levels can lead to weight gain, high blood pressure, and can have cascading effects that decrease sleep time and sleep quality. Ultimately, this can put sleep-deprived people at risk for diseases such as heart disease and diabetes.[5]

Sleep and cortisol levels under stress

True to its name as a stress hormone, cortisol levels become elevated in times of stress.  When you are stressed out, the heightened cortisol serves to increase brain activity during sleep, which reduces the amount of time you spend in slow-wave sleep, causing lighter sleep, and waking up frequently throughout the night.[3]

Cortisol and sleep deprivation

Now that you’ve read about the link between sleep and cortisol and how cortisol can cause sleep disturbances during stressful times, let’s take a look at the connection between lack of sleep and cortisol.  

Sleep loss serves to elevate cortisol levels, which has implications for not only the body’s ability to leverage stress responses under sleep deprivation, but also could lead to metabolic and cognitive consequences resulting from elevated cortisol.[6]

Cortisol and weight gain

In addition to the link between cortisol and sleep, there is a link between cortisol levels and weight gain. Many people stress-eat as a coping mechanism in tense times, which can cause weight gain. Chronic stress is known to boost hunger and therefore cause weight gain in the longer term as well.[7]

The relationship between cortisol and sleep and weight gain is most evident in times of sleep deprivation. Lack of sleep contributes to elevated cortisol levels, which causes the body to develop insulin resistance, an inability of the body to release insulin in response to heightened glucose levels.  

Insulin resistance, therefore, reflects the body’s failure to properly control blood glucose. It is a key component of both prediabetes and type 2 diabetes.[8] Just one night of sleep deprivation can create conditions of insulin resistance equal to six months on a high-fat diet![9]  Luckily, in the short term, insulin resistance created by sleep loss can be reversed by catching up on sleep.

You may be wondering about how to lower cortisol levels and lose weight.  Sleep seems to be a major player in reducing stress and, by association, cortisol.  You can read more about the link between cortisol and weight loss, and how sleep can help you reach your weight loss goals, here.

Should I test my cortisol levels?

You may be tempted to pay for a cortisol test.  Cortisol testing has now become a commercial enterprise, with companies offering mail-in testing based on salivary cortisol as well as urine and blood.

You should speak to a doctor about obtaining cortisol testing to ensure that it is the proper choice for you. Many cortisol test companies work together with doctors’ offices to ensure that medical professionals can review and interpret your test results.

How can I lower my cortisol levels naturally?

In general, it is a good idea to reduce stress in your life as much as possible to avoid the negative impact of chronic exposure to cortisol. There are many ways to naturally lower cortisol. A few ways to reduce your cortisol levels include:

Engage in mild to moderate exercise. 

Cortisol levels increase after a heavy workouts as your body seeks to repair its muscles.[5]  To ensure that your cortisol levels stay low, engage in mild to moderate exercise several times a week rather than engaging in very strenuous workouts.  

Working out less strenuously will also lower your risk for injury in addition to reducing the natural cortisol response following your workout.

Consider taking adaptogens to promote a healthy stress response.  

Adaptogens such as Polygala can help the body cope with stressors by reducing cortisol levels, lower blood sugar, improve brain function, and combat depression and anxiety.[10]  

Sleep seven to nine hours each night.  

Your body’s cortisol levels naturally dip between 12 am and 9 am which helps to promote sleep and decrease alertness, which is one of the many functions of the stress hormone. Sleep deprivation can boost cortisol at night which can make it even more difficult to fall asleep. If you are having problems sleeping, consult with a sleep specialist who can help find the right solution for your sleep problems.

Use meditation or yoga to control stress.  

Seek to control life’s stresses through healthy coping mechanisms such as meditation or yoga.  Stress reduction also attenuates production of cortisol and can also help you sleep better. You may wish to take a yoga class at a studio, or use Remrise’s sleep meditations to transition your mind from alert mode into a sleep-ready state in the evening.

To reduce cortisol levels, you can consider sleep to be your best tool to reduce the harmful effects of too much of this stress hormone. Sleep is the secret ingredient to cortisol regulation, and can help repair the body’s cells and tissues which may be damaged by the effects of stress.


Cortisol: A major stress hormone which regulates a variety of processes including metabolism, energy mobilization, alertness, and other important physiological processes to facilitate the body’s “fight-or-flight” response.

Insulin resistance: An inability of the body to properly regulate blood glucose levels using insulin.


  1. “What is cortisol?” WebMD.  Available at
  2. “Chronic stress puts your health at risk.” Mayo Clinic.  Available at
  3. Hudson, Tori.  February 6, 2017.  “Cortisol and sleep: The HPA axis activity connection.”  Integrative Therapeutics. Available at
  4. “More Evidence: Untreated Sleep Apnea Shown to Raise Metabolic and Cardiovascular Stress.”  Johns Hopkins Medicine. Available at
  5. Thorpe, M. April 17, 2017.  “11 Natural Ways to Lower Your Cortisol Levels.” Healthline.  Available at
  6. Leproult R et al.  1997. “Sleep loss results in an elevation of cortisol levels the next evening.”  Sleep. Available at
  7. Breeze, J. “Can stress cause weight gain?” WebMD.  Available at
  8. “Insulin Resistance.”  National Institute of Diabetes and Digestive and Kidney Diseases.  Available at
  9. “Insulin sensitivity: One night of poor sleep could equal six months on a high-fat diet, study in dogs suggests.”  Science Daily. Available at
  10. Spritzler F. June 11, 2018.  “12 Proven Health Benefits of Ashwagandha.”  Healthline. Available at

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