A good night's sleep is important for your physical and mental health. High-quality sleep means more than just spending eight hours in bed. You should be able to fall asleep easily and wake up feeling refreshed.
As you sleep, you'll progress through the sleep cycle without waking up completely. Unfortunately, this isn't always as easy as it sounds. Stress hormones like cortisol are a big contributor to poor sleep. In this article, we'll explore how the stress hormones and sleep cycle affect each other.
What Are Stress Hormones?
What do driving to work, running a marathon, or drinking a big cup of coffee have in common? All of these actions trigger the release of cortisol, known as “the stress hormone.” Cortisol plays a role in regulating everything from sleep to metabolism.
The HPA axis includes your hypothalamus and pituitary gland in your brain and the adrenal glands near your kidneys. When you feel physical or emotional stress, the hypothalamic pituitary adrenal (HPA) axis jumps into action. The hypothalamus and pituitary gland send a signal to your adrenal gland to release cortisol.
How Cortisol Affects Your Sleep
As your cortisol levels increase in response to stress, you may feel physical symptoms like an increased heart rate or rapid breathing. You may also feel more alert. This gives the body the energy it needs to cope with a threat. While this is useful when encountering a bear in the woods, high-stress hormones negatively affect your ability to sleep. That is because the release of cortisol immediately causes several physiological changes that are not conducive to sleep. These include:
- Rapid breathing
- Increase in blood sugar
- Increase in heart rate
Stress Hormones and Your Circadian Rhythm
The balance between stress hormones and your sleep-wake cycle or circadian rhythm is delicate. Your body needs cortisol as part of your sleep-wake cycle. Cortisol levels will increase and decrease throughout the day to ensure that you are ready to sleep at bedtime and ready to wake up in the morning. During the second half of the night, your body releases more cortisol to prepare you to wake up. Your cortisol levels reach their peak in the morning. As the day progresses, your cortisol levels decline. They reach their lowest point by midnight.
As cortisol declines in the evening, the pineal gland in your brain produces melatonin. During the night, your melatonin levels will be at their highest. When your cortisol levels are high during the day, your melatonin levels will be low.
What Factors Affect Stress Hormones and the Sleep Wake Cycle?
If you lie in bed at night unable to fall asleep, the cause might be elevated cortisol levels. Cortisol keeps you alert and ready to respond to danger. If the cortisol levels don't decline in the evening, you may remain in this heightened state. You may have difficulty falling asleep. When you do sleep, you may experience more disruptions. Some people wake up more frequently or feel like they didn't sleep at all.
- Stressful life events (SLEs) - These have have been consistently linked with increased cortisol levels. When the cause of your stress is temporary, like a wedding or exam, your sleep cycle may return to normal after the event is over.
- Exercise - Intense exercise increases levels of cortisol in your bloodstream. But, this increase is only temporary. You should still exercise as it’s extremely beneficial overall. The key though is to time intense work outs more than three hours before bed. That way it doesn’t affect your sleep. Also, make sure you take plenty of time after working out to recover and wind down.
- Chronic stress - Severe stress from chronic illness, ongoing relationship issues or unemployment, can last longer and have long-term physical effects. Research shows that people living below the poverty line or dealing with chronic work overload get less sleep. Some people may become stuck in a cycle where high cortisol levels trigger more sleep problems. These sleep problems continue to trigger more cortisol production.
The Relationship Between High Cortisol and Sleep Disorders
Most people will have trouble falling asleep occasionally. If you have trouble falling or staying asleep over a longer period, you may have insomnia. Insomnia is a serious disorder that can lead to obesity and depression. Research shows a correlation between elevated cortisol levels and insomnia. Some studies show that high cortisol levels in the morning can cause insomnia. Other studies show that high cortisol levels in the evening can lead to insomnia.
Research shows that high cortisol levels are also related to conditions like obstructive sleep apnea (OSA). If you have obstructive sleep apnea, your airway becomes partially or completely blocked while you sleep. You may stop breathing multiple times during the night. One of the most common warning signs of OSA is snoring. You also may wake up frequently during the night or wake up feeling tired. OSA raises your risk for diabetes and cardiovascular disease.
How to Fight Back Against High Cortisol Levels
If you want to get better quality sleep, you can start by lowering your cortisol levels. Here are some ways to do that:
- Reduce or eliminate foods that can trigger cortisol production - Although that cup of coffee may help you wake up in the morning, the caffeine also can raise your cortisol levels. Research shows that eating sugary foods can also increase your cortisol levels.
- Consider supplements like ashwagandha - Some OTC supplements may be able to help reduce your cortisol levels. Ashwagandha is an herbal supplement that acts on the HPA axis to reduce cortisol levels.
- Try relaxation training - In addition to dietary changes and supplements, meditation, mindfulness, and breathing exercises can help you relax in the evening. Adding breathing exercises to your bedtime routine may help you fall asleep.
If you're experiencing stress in your life that is keeping you up at night, one culprit could be high cortisol. You don't have to suffer through sleepless nights or restless sleep. Understanding the link between stress hormones and your sleep cycle can help you find solutions to this common problem.
