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  • Sleep

    Importance of Sleep to Your Immune System

    Toni Gam - Swisse Author
    Written by Toni Gam | Swisse Nutritionist
    sleep and immune system health

    Rest is a vital part of our immune system, but unfortunately, it’s often overlooked. Many of us opt for spending late nights working or binge-watching TV instead of sleeping. While it’s tempting to catch up on Disney classics before bed, Sleeping Beauty may have had the answer we’ve been looking for all along. Quality sleep positively impacts our overall health and wellbeing. If you’re wanting my late-night TV recommendation for good health, I’d recommend the back of your eyelids.

    Sleep disorders are a common problem in Australia, with over 1.2 million Australians estimated to experience sleeping problems.1 Sleep is an essential element of living and keeps us happy, healthy and sniffle-free.

    What happens when we sleep?

    Sleep is essential for our bodies, as it enables us to filter and process what we’ve done throughout the day. Sleep impacts our alertness, tiredness and cognitive function.2

    The sleep/wake cycle, known as our circadian rhythm, is part of our nervous system and is controlled by the hypothalamus. When it’s dark at night, our eyes send a signal to the hypothalamus to say that it’s time to feel tired. Our brain then sends messages to release melatonin, which increases tiredness. When we sleep, the body repairs and restores our muscles and organs and enables our immune system and metabolism to reach a balance, known as homeostasis.

    The need for sleep

    There’s a communication network between the immune system and our nervous system. Neurons and immune cells share intercellular signals, such as hormones, cytokines, neurotransmitters and modulators.2 Our immune system is regulated by our nervous system directly via hormones and indirectly through blood flow, blood pressure and lymphatic flow.3 Conversely, our immune cells traffic to all the cells in the body and come into close contact with nerve endings.

    When we’re asleep, the body enhances the consolidation of both our neurobehavioral and immunological memories.2 These memories form the basis of the body’s memory, creating its’ ability to adapt to future stressors.2 Without sleep, the body is deprived of this memory formation, and may not be able to adapt as adequately with reoccurring stressors.

    What happens when we’re asleep?

    At the beginning of the sleep cycle, the body releases pro-inflammatory cytokines. Essentially, the body is responding to ‘danger signals’ that have occurred throughout the day, including physical activity and cell injury.3 In turn, these pro-inflammatory cytokines support out immune responses. If we’re sleep-deprived, the body still exerts an inflammatory response, leaving us feeling weak and fatigued. These pro-inflammatory mediators rise when we don’t get enough sleep, increasing our overall bodily inflammation.3

    While we’re asleep, the body also releases immunoregulatory cytokines, such as interleukin (IL)-1, impacting our immune system.

    When we don’t get enough sleep

    Loss of sleep can infer a negative impact on our immune system and suppress our immune response. While excessive sleep won’t stop you from getting a cold, sleep deprivation makes us more susceptible.3 Sleep deprivation decreases our production of lymphocytes and natural killer cells, which plays an important role in our immune system.3

    Sleep deprivation can increase our stress hormone cortisol, suppressing immune system function and reducing our ability to fight inflammation.2

    When we fall sick

    When we do get a cold, our demand for sleep increases.4 It’s so important to listen to this signal and allow your body to sleep to recover as quickly as possible from illness.

    We encourage you to prioritise your sleep. We recommend that you create a beautiful night time routine to help you drift off peacefully and support your immune system.


    1Hechtman, Leah 2012, Clinical Naturopathic Medicine, Elselvier, Sydney.

    2 Besedovsky, Luciana, et al., 2011, ‘Sleep and immune function’, European Journal of Psychology, vol. 463 no. 1 pp. 121-137

    3 Asif, Nayyab, et al., 2017, ‘Human immune system during sleep, American Journal of Clinical and Experimental Immunology, vol. 6 no. 6 pp. 92-96

    4 Benington JH, et al., 1995, ‘Restoration of brain energy metabolism as the function of sleep’, Process in Neurobiology, vol. 45 no. 4 pp. 347-360