We all know the importance of a good night’s sleep for mental health and energy, but there’s so much more that goes on at night than simply resting. Sleep provides a break for the body to repair and clear cellular debris that can slow the immune system down, keeping your immune system resilient and responsive.
Let’s look at how sleep and immunity are connected, and how you can support both with simple, sustainable habits.
What Happens to the Immune System During Sleep?
Sleep isn’t just a time to rest, it’s a time to repair, remove and restore.
Sleep – especially deep, slow-wave sleep – is a key time for immune regulation, repair, and memory. During this phase, the body shifts into a state of restoration, which allows your immune cells to operate more effectively.
Here’s what the immune system is doing during sleep:
- Cytokine production increases: These signalling proteins help coordinate the immune response, directing white blood cells where they’re needed and supporting inflammation control.1
- Immune system memory is strengthened: While you sleep, your body helps to train immune cells to better recognise and respond to pathogens.1
- Tissue repair and detoxification increase: Damaged cells are cleared out and antioxidant activity increases – helping the body recover from daily stress and toxin exposure.2
- T cells become more active: T cells are a type of white blood cell that recognise and target viruses and infected cells. Research suggests they become more efficient during sleep.3
The Body Clock, Sleep and Immunity
The circadian rhythm is the body’s internal 24-hour clock. It helps to regulate the sleep-wake cycle, hormone production, digestion and immune activity. Everything from energy levels to immune defences runs more smoothly when this rhythm is steady.
One of the key players in this cycle is melatonin, a hormone naturally produced by the brain in response to darkness. Melatonin not only signals that it is time to sleep, but also acts as a powerful antioxidant and immune modulator – even reducing inflammation.4
When this rhythm is disrupted by irregular bedtimes, blue light exposure at night, or ongoing stress, melatonin production is hindered. To maintain immune resilience, it’s key to keep the circadian rhythm in check.
The Stress-Sleep-Immunity Triangle
The connection between stress and poor immunity is well known and supported by mounting evidence, but it’s also common sense. Rest is one of the most important components of recovering from illness, so it makes sense that sleep is also key in supporting the immune system. Stress raises levels of the hormone cortisol, disrupting sleep and interfering with immune function. Poor sleep, in turn, raises stress levels, and the cycle continues.
Breaking the stress-illness loop starts with small, consistent steps to support deeper rest and reduce everyday tension.
Simple Ways to Sleep Better and Support Your Immune System
You don’t have to completely overhaul your life to improve your sleep and immunity. Just a few small changes can make a big difference:
- Keep a regular sleep routine, even on weekends
- Limit screen time before bed to support healthy melatonin production
- Avoid heavy meals or alcohol too close to bedtime
- Create a calming wind-down ritual, such as a warm bath or shower, herbal bedtime tea, light reading, gentle yoga, or a sleep meditation
- Aim for 7–9 hours of quality sleep most nights
- Avoid stressful forms of media – including social media – for at least an hour before bedtime
- Manage daily stress with movement, mindfulness, or breathing techniques
Nutrients That Nourish Sleep and Immunity
Alongside healthy habits, the right supplements can gently support your body’s natural sleep-immune connection.
Key ingredients to support sleep and immunity:
- Magnesium – helps relax muscles and calm the nervous system for deeper sleep
- Vitamin C – supports immune cell function and antioxidant protection
- Zinc – crucial for immune defence and cell repair
- Vitamin D – important for immune regulation, especially in the darker months
- Herbal medicines like passionflower and lemon balm – naturally calming, anti-anxiety, and sleep-promoting
Supporting your immune system doesn’t have to be complicated. Prioritising sleep is one of the most powerful, natural ways to strengthen your body’s defences, regulate inflammation, and help you feel more like yourself every day.
It’s not just about sleeping more, it’s about sleeping better. And when you do, your whole system benefits.
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This article was written by Sophia Power, a Clinical Nutritionist.
References:
- Besedovsky, L., et al. (2011). Sleep and immune function. Pflugers Arch, 463(1):121-137. https://pmc.ncbi.nlm.nih.gov/articles/PMC3256323/
- Williams, J.A., et al. (2021). Sleep and cellular stress. Curr Opin Physiol, 15:104-110. https://pmc.ncbi.nlm.nih.gov/articles/PMC7008961/
- Dimitrov, S., et al. (2004). Sleep associated regulation of T helper 1/T helper 2 cytokine balance in humans. Brain Behav Immun, 18(4):341-8. https://pubmed.ncbi.nlm.nih.gov/15157951/
- Cho, J.H., et al. (2021). Anti-inflammatory effects of melatonin: a systematic review and meta-analysis of clinical trials. Brain, Behaviour, and Immunity, 93: 245-253. https://www.sciencedirect.com/science/article/abs/pii/S0889159121000386