How does sleep affect the immune system?

Sleep and your immune system

When it comes to looking after your immune system, most of us know how important things like diet are, but did you know that sleep can have a huge effect too?

This is something that has been researched for many years, and scientists are still trying to figure out the exact relationship between sleep and the immune system. However, what they do agree on is that a lack of sleep can severely impair your immunity and make you more vulnerable to infections like colds and flu.

How does sleep deprivation affect the immune system?

This is quite a complicated subject and there are lots of theories about the role of sleep and the circadian rhythm in our immune function. Basically, what the research shows is that getting enough sleep is vital for the immune system and without enough sleep you are more vulnerable to infections like colds, flu and coughs.

So let's take a look at a few studies which show how exactly sleep might support the immune system.

Firstly, many studies suggest that sleep actually helps our bodies to create the immune cells we need to fight off pathogens. For example, one study found that serum interleukin-7 (IL-7) concentration increased significantly during sleep¹. IL-7 helps to create immune cells such as T cells and B cells, so this is really useful!

Another study found that sleep helps to shift the balance of IL-10 and IL-12 (both involved in the regulation of the immune system and development of immune cells) to ‘globally increase the efficacy of adaptive immune responses’.²

However, it is also thought that sleep affects different parts of the immune system in different ways. For example, one study found that during sleep, immune cells such as monocytes, NK cells and lymphocytes were reduced, but during the day following good sleep, levels were significantly higher than in those who had not slept the night before.³  

In addition, one study involving mice found that sleep deprivation actually reversed the effects of influenza immunisation, ‘such that sleep deprived animals behaved as though they had never been immunized’⁴. Animal studies don't always mirror exactly human experiences and responses, but they do give us a good idea. In this case, this animal study provides yet more evidence that sleep is vital when it comes to good immune health – and that if you're getting the flu jab this year you might want to get a good night's sleep afterwards!

How much sleep do I need?

Different people will require different levels of sleep depending on the unique make-up of each of our bodies. However, as a general rule of thumb, we suggest that adults get at least 8 hours a night, while teenagers require between 8 and 10, and children need at least 10, if not more!

If you're already sick, don't be afraid to take some time off work to make sure you can get the sleep you need. Even while you're not sleeping, try to take things easy and take a nap if you need to. Your body needs this rest time to repair itself!

How to sleep better for the immune system

• Avoid using tablets or phones in bed, as the blue light will stimulate the brain and keep you awake for longer
• If you’re having trouble getting to sleep earlier, try slowly dimming the lights in the hour leading up to bed time to simulate the setting sun. This will trigger the release of melatonin, our sleep hormone
• Try Dormeasan to support a natural sleep cycle. It can help you drift off when you go to bed, or help you to fall asleep again if you wake up in the middle of the night.
• Broken sleep is poor quality sleep and will not help the immune system. If you wake up during the night, pay attention to what time you wake up, as this could indicate problems with certain organs. For example, waking at 3am is often a result of a stressed liver
• Avoid caffeine in the afternoon and evening. This can stay in the bloodstream for hours, so even that 3pm pick me up could still be causing trouble by 10pm when you're trying to wind down
• Check your mattress. You might be surprised how much better you sleep just from changing your mattress! A comfier bed will help you sleep faster, but it will also help to sustain a long and deep sleep
• If a blocked nose is keeping you awake, try to prop your head a little higher and use a nasal spray to loosen congestion. 
• If you do happen to catch a cold or flu, then our Echinaforce range can be a great way to ease your symptoms to get a better night's sleep.

^{1) Brain, Behaviour and Immunity, 'Sleep enhances serum interleukin-7 concentrations in humans', Nov 2007}

^{2) Archives of Internal Medicine, 'Shift of monocyte function toward cellular immunity during sleep'. Sept 2006}

^{3) Journal of Immunology, 'Effects of sleep and circadian rhythm on human circulating immune cells', May 1997}

^{4) Regional Immunology, 'Suppression of immunity to influenza virus infection in the respiratory tract following sleep disturbance', Sept 1989}