The Impact of Stress on Sleep
In response to acute stress, our body produces adrenaline, to help us with the fight or flight response. When our body perceives there is an immediate threat to our lives, this activates our Sympathetic Nervous System (SNS) to increase our heart rate, respiratory rate, stop non-essential functions such as digestion and produce stress hormones. During acute stress you may experience issues falling asleep and entering the restorative sleep stage as your body believes your life is in danger so prevents you from entering a deep sleep in case you need to fight or flee during the night.
Once the threat has diminished the Parasympathetic Nervous System (PNS) is activated to lower our heart rate, respiratory rate and stop the production of stress hormones. Evolutionarily this response was useful as we had to fight for survival if, for example, a bear was going to attack us. However now our stressors tend to be due to relationships, financial stresses, or work-related stress. Things we are unable to run from, which can cause long term stress and SNS dominance.
Long term stress increases our cortisol production. Cortisol is normally at its highest peak in the morning to help us wake up, get out of bed, and have enough energy for the day. Levels of cortisol steadily decrease during the day, reaching its lowest point at around 10pm. This is so we are relaxed and able to fall asleep. When cortisol levels are low, the PNS is activated during sleep and we enter the restorative period of sleep. Cortisol levels start to slowly rise again at around 2am. If you are experiencing long-term stress you may wake up at around 2am/3am as cortisol levels are already high.
To help reduce stress, you need to allow your body to feel safe. Here are some tips to help reduce stress and improve sleep:
- Stick to a good sleep routine but try to go to bed earlier rather than later. If we are constantly stressed the PNS system may only be dominant during times we are asleep. As PNS is only dominant until around 2am, going to bed around 10pm will provide you enough time to rest and restore. Check out our Circadian Rhythm blog to help figure out your optimal time to go to sleep.
- In times of acute stress, exercise is important, so we move our bodies as if we are acting upon the fight or flight response. However, in terms of long-term stress more restorative exercise, such as yoga, may be helpful as this activates our PNS. High-intensity exercise activates our SNS as it increases our heart rate and respiratory rate, so try to incorporate restorative exercises into your routine as well. Remember exercise outside in the morning is better as it increases melatonin production for release later in the day to help you fall asleep.
- Try deep belly breathing when you are feeling stressed to helps you to feel relaxed. When we are stressed, we tend to breathe short quick breaths from our chest instead of long deep breaths from our stomach.
- Allocate time during the day to write down your worries and your to-do list as this will prevent you from worrying about them as you try to fall asleep.
- Try to reduce caffeine intake. When we do not enter the restorative stage of sleep, we can wake up feeling unrefreshed and groggy, this can cause us to make a cup of coffee to increase our energy. However, caffeine also increases cortisol so try to reduce the amount of caffeine you consume, at least try to stop caffeine intake after lunchtime as this can increase difficulty in falling asleep. If you improve your sleep practices you are likely to feel refreshed in the morning, making it easier to reduce your caffeine intake.
- Avoiding screens and working in the 2 hours before bed allows us to wind down and help us to switch from SNS to PNS. If we engage in work or see something on social media that causes our stress levels to rise, then this may cause us difficulty falling asleep.