What happens to your body when you are sleeping?

What happens to your body when you are sleeping?

Sleep is a vital aspect of our daily routine that helps our bodies and minds to recharge, refresh and rejuvenate. It is a state of rest characterized by a reduction in consciousness, muscle activity, and sensory perception. The science of sleep is a complex and fascinating field that explores how our bodies and minds respond to and recover from sleep.

In this blog, we will delve into the science of sleep and examine what happens to our bodies when we are sleeping.

Sleep Stages

Sleep is divided into two main categories: Rapid Eye Movement (REM) sleep and Non-Rapid Eye Movement (NREM) sleep. NREM sleep is further divided into four stages. The first three stages are referred to as N1, N2, and N3, while the fourth stage is referred to as REM sleep.

Each sleep stage has a different impact on our bodies and minds, and we cycle through all five stages several times throughout the night.

Stage N1: This is the stage where you first fall asleep and are in a state of light sleep. Your muscles start to relax, and your eyes move slowly. This stage lasts for only a few minutes.

Stage N2: This stage is characterized by deeper sleep, and your heart rate, temperature and breathing start to slow down. This stage lasts for about 25 minutes or more and plays a key role in memory consolidation.

Stage N3: This stage is the stage of deep sleep, where your muscles are completely relaxed, and you are in a state of restorative sleep. During this stage, the body engages in processes that promote tissue repair and growth, strengthen bones and muscles, and boost the immune system. This stage lasts for about 30 minutes and is the most difficult to awaken from. As you age, less time is spent in stage N3, and more time is spent in stage N2.

REM Sleep: This stage is the stage of vivid dreaming, and your eyes move rapidly. Your muscles are temporarily paralyzed to prevent you from acting out your dreams. During this stage, your heart rate and breathing become irregular, and your brain is more active than during other sleep stages. This stage lasts for up to an hour¹.

Importance of Sleep

Sleep plays a critical role in our physical and mental well-being. During sleep, several restorative processes occur that help to maintain our physical and mental well-being. Some of these processes include:

  • Consolidation of Memory: Sleep helps to consolidate memories and information that we have acquired during the day. This process helps to reinforce and improve our ability to recall information.
  • Repair and Growth of Tissues: During deep sleep (N3 stage), the brain releases growth hormone, which helps to repair and rejuvenate tissues and muscles.
  • Regulation of Hormones: Sleep helps to regulate hormones that control appetite, metabolism, mood, and stress levels.
  • Boosting the Immune System: During sleep, our immune system releases cytokines that help to fight off infections and diseases.
  • Clearing of Waste: Sleep helps to clear waste from the brain, reducing the risk of neurodegenerative diseases such as Alzheimer's and Parkinson's.
  • Stress Reduction: Sleep helps to reduce stress levels, lowering the risk of chronic stress-related conditions such as anxiety and depression.
  • Improved Mental Function: Sleep helps to improve attention, concentration, and memory, allowing us to perform better mentally during the day.

Overall, sleep provides a vital opportunity for our bodies and minds to recover, recharge, and rejuvenate, ensuring that we can function at our best. Regular, adequate sleep helps to regulate hormones, boost the immune system, enhance brain function, reduce stress, and improve mood. If you are having trouble sleeping, it is important to speak with a doctor and determine the underlying cause. By making sleep a priority and incorporating healthy sleep habits, you can reap the many benefits of a good night's sleep.

Top tips to get a good night’s sleep:

Here are some general tips for getting a good night’s sleep. What works for one person may not for another, so it is best to experiment with different habits to find what works best for you. If you have had ongoing sleep issues, or continue to struggle despite doing what you can, we would recommend speaking with a doctor.

  • Stick to a consistent sleep schedule: Go to bed and wake up at the same time every day, including on weekends. This helps regulate your body's internal clock and makes it easier to fall asleep and wake up.
  • Create a sleep-conducive environment: Make your bedroom cool, dark, and quiet. Use curtains, blinds, or an eye mask to block out light, and invest in a comfortable mattress and pillows.
  • Limit exposure to screens: The blue light emitted by electronic devices can suppress melatonin, making it harder to fall asleep. Avoid screens for at least an hour before bedtime.
  • Avoid caffeine and alcohol: Caffeine and alcohol can interfere with sleep quality and make it harder to fall asleep. Limit or avoid these substances in the hours before bedtime.
  • Exercise regularly: Regular exercise can improve sleep quality, but it is important to avoid vigorous exercise close to bedtime.
  • Relax before bed: Engage in relaxing activities before bed, such as reading a book, taking a warm bath, or practicing meditation or deep breathing.
  • Avoid napping: Avoid taking long naps during the day, as this can disrupt your sleep-wake cycle and make it harder to fall asleep at night.
  • Consider a white noise machine: If you are easily disturbed by outside noise, consider using a white noise machine to help block out distractions and promote sleep.
  • Supplements: There are many supplements that can be used to support sleeping difficulties, a few of which are listed below. Supplementation should be used in conjunction with these tips.
    • Melatonin or supplements that mimic melatonin’s effect in the brain. Melatonin is a hormone that helps regulate our sleep-wake cycle. It is commonly used to help with sleep onset difficulties and insomnia.
    • Crocus sativus (Saffron) is a herb that is used to improve sleep quality and promote restorative sleep.
    • Passiflora incarnata (Passionflower) is a herb that is commonly used to promote relaxation and reduce anxiety. It may help to improve sleep quality and support falling asleep.
    • Withania somnifera (Ashwaghanda) is a herb that gently supports the body to respond to stress. It is a well-tolerated and supports falling asleep and improves sleep quality.
    • Valerian officinalis (Valerian Root) is a herb that is used to promote relaxation and improve sleep quality. It may help to reduce stress and anxiety, allowing for a deeper, more restful sleep.
    • L-Theanine is an amino acid found in green tea that helps to promote relaxation and reduce stress levels. It may help to improve sleep quality and reduce sleep onset difficulties.
    • Magnesium is an important mineral that helps regulate sleep patterns and muscle function. It is commonly used to help with sleep onset difficulties, muscle cramps, and restless leg syndrome.
    • CBD or phytocannabinoids that mimic CBD’s effect in the brain can promote relaxation and sleep.

Suzy Walsh 

BBA (Hons)., BNat., mNMHNZ

Registered Naturopath & Medical Herbalist


¹ Patel, A.K., Reddy, V., Shumway K.R., et al. (2022) Physiology, Sleep Stages. [Updated 2022 Sep 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526132/