A good night’s sleep can stop a person from getting ill, Luke O’Neill has said. 

The Trinity Professor said getting a good night’s sleep is “extremely important” and is about far more than just feeling fresh and well rested the next morning. 

That being said, the amount of hours asleep that people need varies from person to person. 

“The average, of course, is seven to eight,” Professor O’Neill told The Pat Kenny Show. 

“As you probably know, most people need eight hours. 

“If you get less sleep, the next day, you’re groggy, your memory isn’t as strong. 

“So, your cognitive powers are lessened.”

A man sleeping in a bed. Picture by: Alamy.com.

As well as a reduced ability to function mentally, Professor O’Neill said a tired person is more at risk of becoming ill. 

“There’s no doubt though, that one function of sleep is to help your immune system,” he said. 

“If you get a bad night’s sleep, the next day, your immune system is less active - that means less antibodies. 

“So, the overall immune system ramps down after a bad night’s sleep. 

“That may be the day you’re sitting beside someone on the Luas or whatever, they cough over you and you’re infected.”

A man sleeping on a couch. Picture by: John Goodlife / Stockimo / Alamy Stock Photo

Professor O’Neill said the reason why living creatures need sleep was a “mystery” for a long-time. 

Roughly a decade ago, scientists concluded that the brain needs sleep in order to “kind of wash itself”.  

“You slosh out all the toxins that build up during the day,” he said. 

“During the day, your brain is buzzing and it’s like a car engine, the exhaust fumes are building up. 

“At night, when you sleep, a thing called the glymphatic opens up and sloshes out all these things that build up. 

“In other words, you’re cleaning your brain.” 

Alzheimer's

More seriously, not getting enough sleep means you heighten your risk of developing Alzheimer's later in life. 

“If you don’t get enough sleep then, the prediction is that some of these things become damaging,” Professor O’Neill said. 

“One of the big things is the risk of Alzheimer’s - and poor Maggie Thatcher [who famously only slept four hours a night], I think she ended up with Alzheimer's.

“So, they reckon that might be part of it; insufficient sleep is a risk factor for that - probably because you’re not cleaning your brain.” 

The HSE has a comprehensive list of activities that will reduce the risk of a person developing Alzheimer's.

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Main image: Luke O'Neill in the Newstalk studio.