How Sleep Affects the Immune System

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Immune health, sleep and the gut are all connected and there are well-established links between the immune system and the gut microbiome in humans. Sleep is a physiological state that is intrinsically linked to the immune system.

When you understand how they all work together you will have an appreciation and respect for your body and how you can look after your own health with so much more power and awareness.

How sleep supports the immune system

  • During sleep, the brain moves through a five-stage cycle, which is important for the body and mind to recover and recharge.
  • Sleep also helps to build T cells which are white blood killer cells (part of the immune system). These T cells attack and destroy viruses.
  • The immune system’s response time is also improved by getting a good night’s sleep.
  • When you’re suffering from a cold, one of the first things your doctor or your mother would tell you is to get plenty of sleep.
  • There’s plenty of research that backs it up. Sleep is probably thing that you can do to deal with, or prevent, colds.

Gut Health & Sleep

Probably the most effective way to resolve your sleep issues and immune health is to improve the health of your gut health. Many people overlook what could be one of the most fundamental causes of poor sleep and that’s poor gut health. And Poor gut health could comprise of parasites in the gut or an overgrowth of bad bacteria and this can cause problems in the gut itself with digestive problems like IBS. Sleep difficulties are common in people with irritable bowel syndrome (IBS). Poor gut health also causes problems systemically outside the gut in the form of brain fog, fatigue and the inability to sleep properly. This relationship between the gut and sleep has been shown in a lot of studies. Some of the studies show people with IBS also have insomnia and as IBS improves so does their insomnia.

Gut Health & Stress

Probably one of the most significant problem that affects the gut is stress. A lot of people are dealing with stress right now and this is probably one of the biggest risk factors to catching any cold or flu or viruses that are going around, because stress directly affects our sleep and our immune system.

Gut Health & The Microbiome

And here’s the thing…70-80% of your immune system is in the gut. Your body is full of trillions of bacteria, viruses and fungi. They are collectively known as the microbiome which is mostly made up of bacteria. Microbes outnumber our human cells ten to one.

The microbiome helps with producing your hormones, brain function, controlling appetite, digestion and your mood. So they help digest our food, protect against bad bacteria that cause disease, they produce vitamins. It also has an impact on the immune system by controlling how your body responds to infection. Friendly bacteria actually “inform” your immune system of what’s happening in your body, to help fight off viruses, infections, support detoxification and basically, keep the peace. Like a referee…

The microbiome also produces and releases many of these neurotransmitters that are associated with sleep; dopamine, serotonin and GABA and these are made in the brain too. 90% of serotonin is made in the gut and serotonin is a precursor to Melatonin. And Melatonin is also produced up to 400x more in the gut than in the brain. Many studies show that Melatonin may help friendly bacteria to synchronise to their circadian clocks. You may have heard me speak about circadian clocks or cycles before, and every cell in the body has one and is primarily influenced by light and dark, day and night and the timing of the food we eat.

Sleep and The Immune System

Microbiome and Sleep

So, what is the relationship between sleep and the microbiome? It turns out that the microbiome affects sleep and sleep-related physiological functions in several ways—disrupting circadian rhythms, altering the body’s sleep-wake cycle, and affecting hormones that regulate sleep and wakefulness. So, for example, scientists have discovered, when our circadian rhythm is disrupted like when we are jet lagged, or doing shift work, this also disrupts the microbiome. On the flip side, our sleep, may also affect the health and diversity of the human microbiome. So sleep and the microbiome have a bidirectional relationship. They very much depend on each other.

So how can we improve our gut health, our microbiome and sleep?

Cleaning up the gut

You can improve your gut health by eliminating toxicity. This helps to improve mitochondrial function which gives our cells energy to function and communicate efficiently. This also in turn helps with better sleep because pathogens and toxins interfere with neurotransmitters involved in sleep.

Simple interventions like taking probiotics and prebiotics can help your gut and help you to sleep better.

Exercising and Movement

Exercise and movement increases blood flow, reduces stress and inflammation, and can strengthen antibodies, part of your immune system. Exercising, moving, getting the blood and lymph flowing all help improve your sleep, keep your immune system strong and overall health.

Dealing With Fear

Fear based narratives are based on greed, control, manipulation, taking away our rights and our power. The narratives are telling us about what is going to happen in the future but that has no bearing on whether it does happen. It has a high probability of playing out if you are playing the game. The narratives are going to get louder. Fear is an illusion and that is what we are dissolving. We are not victims. That narrative wants us to feel fear, stress, worry, concern, panic etc. When you continue to feel it, you are playing that narrative out and you are suppressing your immune system. The psychological impact of the pandemic, can cause anxiety and depression. You may be putting yourself at undue risk, because any fear based emotions like anxiety suppresses the immune system and increases our risk for infection.


Lack of sleep can negatively affect your immune health and increase your risk of diseases and infection. Having a strong immune system is critical to your overall health. Improving your sleep starts with good habits, routine and a good environment, especially your bedroom. This is also known as good sleep hygiene. Keep consistent sleep schedules and don’t bring your phone to bed with you at night.

If you enjoyed this article and want to know more, I have a special short course ‘Boost Immunity with Better Sleep‘ 7 Day Sleep Video Series, currently at 50% off for a limited time.

Remember, sleep is your greatest asset. Make it a priority!