The effect that sleep – or the lack thereof – can have on our immune system is something that we probably don't think about enough, especially considering all the pandemic-related reasons we have to stress ourselves out.

As part of Today with Claire Byrne’s ongoing series on boosting the immune system, Professor Clíona O’Farrelly, Chair of Comparative Immunology at Trinity College, spoke to Claire about the effect poor sleep can have on our ability to fight diseases and even on how we look. 

Prof O’Farrelly told Claire that we feel better and we look better after a good night’s sleep: 

"We now know that immune activity in the brain is really important during sleep for clearing up the bits and pieces of proteins that are hanging around that need to be cleared. And that’s probably the same for all our tissues in our liver, in our skin, that our immune system is working away." 

The question we want answered though, is put to Prof O’Farrelly by Claire – does a lack of good sleep increase our chances of getting sick? The short answer is yes. Yes, it does: 

"There’s increased incidence of auto-immune disease, of infection and worsening of cancer, when we can’t sleep properly." 

Something that a pandemic-weary population probably doesn’t want to hear is that, Prof O’Farrelly says, alcohol is actually counter-productive for sleep, even though we might think of it as making us feel sleepy, because the quality of the sleep we get when we’ve had a few is poorer than if we’d kept the cork in the bottle.

Then Prof O’Farrelly explains why we sometimes wake up feeling hot after we’ve been drinking: 

"We’re hot because our poor livers are struggling away to deal with the alcohol." 

It’s at this point that Claire has to press the pause button on proceedings – just to process the notion of our poor old livers getting all hot and bothered trying to deal with the poison we’ve imbibed. And it is an arresting image when you think about it – no, your duvet isn’t too heavy, you’ve just had one to many and your liver is working overtime to deal with the consequences.

As Claire says, "quite frightening, isn’t it?" And because of all the work the liver’s putting in to rid the body of alcohol, the immune system can’t do its job properly. 

Another aspect of sleep and its effects on the immune system relates to when we go to sleep. This is where our circadian rhythm comes into play and Prof O’Farrelly says that going to bed very late can affect our melatonin levels. What does that mean? Well, it’s not good, as melatonin is important for controlling the body’s hormones and also has an immune effect.

So, the take-away is, go to bed earlier, folks: 

"The longer before midnight that you go to sleep, the better chance you’ll have of going to sleep and the better chance you’ll have of a good quality sleep." 

Cut down screen time, get some exercise and go to bed earlier. Sounds like common sense. 

To hear the full conversation between Claire and Professor Clíona O’Farrelly – including Prof O’Farrelly’s must-hear recitation of the immune system-focused poem, Glymphatically Yours – go here