Sleep and stress: the impact of cortisol on your sleep quality

What is cortisol and how does it affect your body?

Cortisol is often referred to as the stress hormone—our body’s natural alarm system that influences fears, motivations, and mood. It functions through a complex system in the body known as the hypothalamic-pituitary-adrenal axis (HPA axis). This system involves three organs that work together to maintain a healthy stress response. The first two are located in the brain and regulate production, while the adrenal glands are responsible for secretion. Cortisol can affect:  

• Inflammatory responses;  
• Blood pressure regulation;  
• The sleep-wake cycle;  
• Energy levels;  
• Blood sugar levels.  

The relationship between cortisol and sleep

How does cortisol impact sleep? Both cortisol and sleep follow a circadian rhythm, governed by various processes. Cortisol levels are at their lowest around midnight and peak at approximately 9 a.m. Research indicates that when the HPA axis is disrupted, the sleep cycle can also be affected, potentially leading to:  

• Fragmented sleep;  
• Insomnia;  
• Shorter sleep duration.  

Sleep problems can further disrupt the HPA axis, creating a vicious cycle. Sleep deprivation may also result in higher cortisol production during the day. 

Risks of high cortisol levels

A temporary increase in cortisol levels is not harmful and serves a purpose in the body, helping to prepare for fight, flight, or freeze responses. However, consistently high levels can lead to sleep problems and contribute to the development of:  

• Weight gain;  
• Inflammation and chronic diseases;  
• Memory issues;  
• Anxiety and depression;  
• Headaches;  
• Cardiovascular diseases;  
• Difficulties with emotional regulation.  

A diet high in processed sugars, fats, and salt—and low in fruits and vegetables—is associated with poor stress regulation, which can affect cortisol levels. Additionally, chronic stress, trauma, and sleep issues can result in persistently high cortisol levels.  

Tips to naturally lower cortisol levels

There are several straightforward strategies to help reduce cortisol levels. Here are some tips:  

• Regular exercise: Moderate physical activity can alleviate stress, reduce the risk of chronic diseases, and promote overall health.
• Relaxation techniques: Practices such as meditation or breathing exercises can activate the parasympathetic nervous system, which is responsible for rest-and-digest responses.  
• Mindfulness: This can help you identify and manage stressful situations and thoughts.  
• Follow a balanced diet: Eating plenty of fruits, vegetables, unsaturated fats, and whole grains can help maintain balanced cortisol levels. Research suggests that prolonged sugar consumption has the opposite effect.  

Certain supplements, such as fish oil, may also have a positive effect on cortisol levels, though further research is needed to fully understand the relationship between supplements and cortisol.  

Nutrition for better sleep

Elevated cortisol levels can negatively impact sleep duration and quality. A healthy diet can support better sleep and more stable cortisol levels. Here are some dietary tips to promote good sleep:  

• Fruits and vegetables;  
• Whole grains;  
• Fatty fish;  
• Water;  
• Legumes and lentils;  
• Dairy products.  

Caffeine and alcohol, on the other hand, can disrupt sleep. It is advisable to minimise their consumption. The most effective dietary choices vary from person to person and depend on any underlying medical conditions.  

Practical tips for better sleep

Small adjustments to your bedtime routine can significantly improve your sleep quality. Here are some practical tips:  

1. Maintain a consistent sleep schedule by going to bed and waking up at the same time every day. This strengthens your biological clock, making it easier to fall asleep and wake up.  
2. Establish a relaxing bedtime routine: take a warm bath, practise yoga, meditate, or read a book.
3. Turn off devices with blue light, such as phones, tablets, or TVs, at least an hour before bedtime.
4. Create an optimal sleep environment. A comfortable mattress, pillow, and blanket, along with blackout curtains and the right bedroom temperature, can help you fall and stay asleep.
5. Reserve the bedroom exclusively for sleeping, not for working, making calls, or watching TV. This helps your body associate the bedroom with sleep, making it easier to doze off.
6. Avoid naps longer than 20 minutes or late in the afternoon.
7. Refrain from eating large meals before bedtime.
8. Spend time in natural daylight during the day and reduce or dim light exposure in the evening.  

These tips can help improve sleep duration and quality, though the effectiveness may depend on any underlying medical causes of poor sleep.  

Conclusion

Cortisol and sleep are closely interconnected. The advice provided in this article can help positively influence both. However, it is important to rule out any potential medical causes for your symptoms before considering medication or supplements. Struggling with sleep? The collaborating doctors at Dokteronline can assess your situation and determine the most suitable treatment—whether with or without medication, depending on your circumstances.