TAKE A SHOWER AT NIGHT TO SUPPORT YOUR IMMUNE SYSTEM

THE past two years spent battling a pandemic have brought into sharp relief the importance of our health and the vital role of our immune systems.

Science has brought us, for a while, effective vaccines for Covid-19. But there is still much to be learned about how we can protect ourselves from this virus and many others.

It’s early days, but there are at least two studies showing that sleep and circadian rhythm disruption in night-shift workers increase the chances of infection and hospitalisation with Covid.

This chimes with other studies showing that disruption to our body clocks impairs our immune systems — and that our individual responses to all sorts of infection change over the day. So, too, do our responses to vaccination and medication.

MORE AT RISK OF COLDS AT NIGHT

WE NOW know that every aspect of the immune response is regulated by the circadian system.

Scientists have discovered that our immunity is generally turned up in the daytime, when we’re active and are more likely to encounter disease, while at night it is turned down, when the chances of encountering new pathogens is much reduced.

Our first line of defence is our skin, an incredibly effective barrier preventing diseasecausing microbes such as viruses, bacteria and other pathogens entering the body.

However, at night — when, if working correctly, our body clocks have every system primed for sleep — our skin becomes more porous, and so more vulnerable to attack.

More water is lost from it and old, dead skin — the topmost layer of defence — is shed, with the highest rate of shedding occurring around midnight.

The loss of water means our skin is that bit drier, which is why anyone suffering with itchiness or conditions such as eczema and psoriasis will suffer more as the evening wears on. (More on this tomorrow in the Mail on Sunday.)

The increased permeability means we are more at risk of bacteria and viruses invading.

Meanwhile, our white blood cells, which attack invaders, are less driven to attack at night — guided by a circadian clock, they’re more active during the day, when we’re usually awake and logically more ‘at

risk’ of encountering infection or injury.

And talking of injury, if you cut or burn your skin, studies suggest it will heal more than twice as fast if the injury was inflicted during the day than at night.

This all makes sense, as it’s much more likely that we will damage our skin while we’re awake and our bodies’ repair systems are primed for action during the daytime.

So how can you reduce these risks? The most obvious way is to work with our circadian rhythms and spend our nights asleep.

Of course, that’s not realistic for everyone — front-line workers in particular. So they should wear protective clothing at work, and all of us should shower at night and vigorously wash our hands and face before bed each night to remove pathogens.

Many of us shower in the morning, but good hygiene in the evening is potentially of much more value to our immunity!

HAVE A FLU JAB IN THE MORNING

GIVEN that our defensive mechanisms rev up in the morning, it would seem logical to give vaccines then.

Indeed, early evidence certainly suggests this is a good idea.

In one study, elderly individuals were vaccinated against a strain of the flu virus either in the morning (9am to 11am) or in the afternoon (3pm to 5pm).

Those vaccinated in the morning had an antibody response three times higher than those vaccinated in the afternoon, when the immune system is beginning to wind down for the night.

AND GET A GOOD NIGHT’S SLEEP

MAKING sure you get a good night’s rest in the days following your jab could also boost its effectiveness.

One study found that people allowed to sleep for only four hours a night after the flu jab had less than half the level of protective antibodies a few days later than those who had slept well.

Similar results have been shown for hepatitis B and hepatitis A vaccination.