1. It clears our brain of waste

When we sleep, the brain’s glymphatic system (its own version of the lymphatic system) helps to flush out the waste that builds up in the brain.

This primarily happens during deep sleep, when interstitial fluid (the fluid that fills the spaces between the body’s cells) combines with cerebral spinal fluid and washes over the brain, collecting waste product and flushing it into the wider lymphatic system in the neck.

This process is particularly important because it helps to clear proteins like amyloid-β, which is linked to Alzheimer’s disease.

2. It supports the immune system

Consistent good sleep strengthens the body’s ability to fight off infections and heal wounds, while also keeping the immune system under control to prevent an auto-immune response.

Research suggests that sleep not only increases the activity of certain parts of the immune system – for example, the production of cytokines that control inflammation in the body – but also helps to improve immune memory so your immune system remembers pathogens it has encountered before and can launch a quicker attack next time it comes across them.

3. It helps to keep our heart healthy

Studies have linked good sleep to a reduced risk of heart disease, which experts believe could be down to a range of factors, including sleep’s impact on blood pressure and heart rate.

According to the British Heart Foundation, studies have shown that disturbed sleep is associated with higher levels of a protein called CRP, a sign of inflammation. Because inflammation can lead to heart and circulatory disease, getting good sleep is beneficial.

4. It promotes good bone health

Our bones aren’t fixed objects – they’re constantly being broken down and rebuilt from the inside. And sleep – particularly our circadian rhythm – plays a crucial role in this process.

By going to sleep at the same time every night and consistently getting a good amount of sleep, we can help our body to achieve a balance between bone resorption (when bone tissue is broken down) and bone formation (when new bone tissue is formed).

It’s for this reason that research has linked lifestyles that lead to a disrupted circadian rhythm – such as shift work and sleep deprivation – to poorer bone health.

Sign up to our Stylist Daily newsletter: the latest news and must-read features so you don't miss out on the conversation.

Get unlimited digital access from £3.49/month