Why sleep should be part of your coronavirus defence plan

As we take every measure possible to protect ourselves from COVID-19, a decent night’s rest could be among the best ways to boost our immune system.

Our bodies are very busy while we’re resting – consolidating memories, repairing muscles, regulating hormones, and working to keep our immune system in top shape.

“When we sleep the body doesn’t have to use its energy to keep us up and running so it goes and does other vital functions,” says sleep expert Dr Carmel Harrington.

“One of those vital functions is keeping our immune system primed.”

How sleep helps our immune system and kills off baddies

Part of our immune defence system is formed of natural killer cells, a type of lymphocyte (white blood cell).

“Natural killer cells fire up when we sleep,” says Dr Harrington.

“What these cells do is go along and kill off viruses and bacteria and mutated cells, they recognise foreign bodies in the body and blow them up.

“If we’re not getting enough sleep our natural killer cell activity can drop by up to 50 per cent.”

Dr Harrington says natural killer cells also prime and activate our adaptive immune system.

“The adaptive immune system is like our memory immune system, and it produces antibodies to the infection,” Dr Harrington says.

“These antibodies – the T cells and B cells – mop up and get rid of the infection.”

The bottom line, says Dr Harrington, is good sleep is vital for fighting current infections and building up a robust response to future infections.

Sleep quality matters too

The sleep cycle comprises non-REM, which includes light and deep sleep, and REM or rapid eye movement.

“It’s completely normal to spend most of our time, up to 60 per cent, in light sleep, then around 20 per cent will be in REM and similarly deep sleep,” Dr Harrington says.

“Deep sleep is something we get a lot of when we’re young, and less as we age.”

While all stages are important, deep sleep has a particularly influential role in maintaining a healthy immune system.

“Deep sleep is when a lot of immune sensors are created and released,” says renowned science presenter and author Dr Michael Mosley.

sleep and coronavirus

How deep sleep may help defend against coronavirus

Part of the body’s self-rejuvenation while sleeping includes washing away waste and toxic proteins, and research shows this happens best during deep sleep.

“Interestingly, we know from COVID-19 the people who’re dying in large numbers are people over the age of 65, and that is because their immune system is not as strong,” says Dr Mosley.

“That could be linked to the fact they’re not getting as much deep sleep.”

Dr Harrington says we can increase deep sleep by exercising more.

“Studies have shown those who exercise get the best amount of deep sleep,” she says.

How much sleep do I need to boost immunity?

Our sleep needs change at different stages of life.

Newborns sleep up to 17 hours a day, while adults generally need seven to nine hours – slightly less for those over 65.

Getting extra sleep won’t stop you from getting sick, but not getting enough can impair its ability to function effectively.

“It’s very stressful to the body not to sleep enough,” says Dr Harrington.

“Your body allows you to do it because it pumps adrenalin and cortisol through your body.

“This firing up of what we call the sympathetic nerves activity is counterproductive with the immune system.”


Quick tips for a better night’s sleep

Create a cosy sleep environment

Televisions, iPads, phones and laptops have all crept into our bedrooms, creating a distraction from sleep.

Dr Mosley says clear all electronics and other unnecessary distractions from your bedroom and use it as a place for sleep and sex, and nothing else.

Establish a sleep routine

Try to go to bed at the same time each night and wake at the same time each morning.

This will support your body’s internal clock so you’ll feel ready for sleep.


“Time and time again studies have shown those people who exercise regularly get better sleep,” says Dr Harrington.

Allow enough time for rest

Dr Harrington says many people simply do not give themselves enough time in bed.

She recommends working out what time you need to wake up and ensuring you’re in bed at least eight hours ahead of that.

Eat well

Dr Mosley recommends a quality, fibre-rich diet.

“There have been studies showing if you eat more fibre, you get more deep sleep,” Dr Mosley says.

He also says highly processed foods can be detrimental to sleep.

Avoid coffee and alcohol

Dr Harrington says these are sleep stealers and should be avoided before bed.

Written by Claire Burke.