A lack of sleep leaves us stressed, tired and likely to overeat – but it also leaves us open to infection.
Sleep could prove to be a lifesaver when it comes to Covid-19 – both in staving it off and minimising symptoms when it hits.
We all know that not getting enough sleep leaves us stressed, tired and likely to overeat, but it also leaves us open to infection.
While it’s too early for any studies to have been done on the effects of sleep on this particular coronavirus (Covid-19), in 2015 researchers in the US deliberately infected 164 volunteers with the rhinovirus (common cold).
They found that the people who slept less than six hours a night were four times more likely to develop cold symptoms than the ones who slept for seven hours or more.
This is because you’re resting when you’re asleep. Through all the phases of sleep your body is building energy, fixing and repairing, but the immune system is particularly boosted during “slow wave sleep”, the first third of the night when we sleep deeply.
“During sleep our immune systems produces and distributes cytokines [a type of protein], and in particular T cells [a type of white blood cell which is crucially important to the immune system]. T cells identify and attach themselves to any infected cells in the body and destroy them – and the infection, too,” says sleep expert Jason Ellis, director of the Northumbria Centre for Sleep Research.
“If you sleep well, you’re not only producing more cytokines but also the T cells become even stickier and more effective at fighting infection.”
A lack of sleep, especially when induced by stress and anxiety, causes a “double whammy” because it creates the “flight or fight” response which activates an inappropriate response from the immune system.
“If you activate it, and it has nothing to do, it creates havoc by producing an inflammation response,” says Prof Ellis.
Depriving yourself of enough deep sleep by overworking does the same thing – so doctors and nurses working double or triple shifts right now are so much more vulnerable, and not just because through exposure to the coronavirus.
“Because it’s their ethical duty and what they choose to do, they’re putting themselves in harm’s way. And if you haven’t slept well before you get a virus, you’re already back-peddling,” says Prof Ellis.
When you have a virus, your body’s immune response will make you sleepy and tired while it does everything it can to fight infection and promote recovery. If you refuse to give in to the urge to rest and nap, it could prolong the illness, not least because your body needs to break out in a fever in order to fight the virus. And fevers most often occur during sleep.
But quite how fever helps in the fight is still relatively unclear, says Prof Mike White who drove a joint study between the University of Warwick and the University of Manchester that proved higher body temperatures drive the body’s immune system to fight infection.
“Fevers are not just a by-product of the illness or a sign that your immune system is doing its job,” says Prof White.
One thing is clear, though; sleep is essential for fever because in the relaxed state, body temperature tends to dip which allows fever to break out.
“During the day the body produces a lot of hormones to keep us walking, talking and reacting, including cortisol and adrenaline,” says Prof Ellis. “At night, you need melatonin to sleep while the production of cortisol and adrenaline reduces so, unencumbered by adrenaline, the fever breaks.”
If you’re just lying in bed and not sleeping, Ellis advises getting up (if you can) and being as active as you can which will help you to sleep when you need – in the form of naps, though try to keep it before 4pm so you can sleep at night.
So while anxiety levels are high and we’re all “sick and tired” of hearing about the importance of sleep, getting enough of it might never have been so important.