{"id":374142,"date":"2026-03-31T04:49:08","date_gmt":"2026-03-31T04:49:08","guid":{"rendered":"https:\/\/www.newsbeep.com\/ie\/374142\/"},"modified":"2026-03-31T04:49:08","modified_gmt":"2026-03-31T04:49:08","slug":"do-we-really-need-eight-hours-sleep-a-night-and-what-happens-if-not-the-irish-times","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ie\/374142\/","title":{"rendered":"Do we really need eight hours sleep a night \u2013 and what happens if not? \u2013 The Irish Times"},"content":{"rendered":"

\u201cOnce, after I did a presentation, someone came up to me and said, \u2018I don\u2019t get eight hours of sleep<\/a> a night. Am I going to die?\u2019\u201d says Prof Russell Foster, head of the Sleep and Circadian Neuroscience Institute at the University of Oxford<\/a>. \u201cAnd I said, \u2018Well, yes, you\u2019re going to die. But, you know, we all die eventually\u2019.\u201d<\/p>\n

This exchange is, hopefully, comforting, but it also shouldn\u2019t be too surprising. Over the past decade or so, we\u2019ve been repeatedly told that sleep is everything from a legal performance-enhancer to an actual superpower \u2013 and, conversely, that if we don\u2019t get enough shuteye we\u2019re risking an early start to our eternal slumber. But how bad is a lack of sleep, really? And if we seem to be coping fine on six hours a night, is there a chance we\u2019re still setting ourselves up for problems further down the line?<\/p>\n

To start with the bad news: yes, being chronically sleep deprived is pretty bad for us. One sobering and relatively recent discovery is the glymphatic system, a waste-clearance mechanism that flushes \u201cmisfolded\u201d proteins like beta-amyloids (found in the brains of people with Alzheimer\u2019s disease) from the brain during rest. Foster points to data showing that poor sleep during the middle years is a risk factor for dementia in later years, because the brain loses its ability to effectively clear these toxins. <\/p>\n

\u201cThere\u2019s increasing evidence surrounding a lack of sleep\u2019s association with cognitive decline later in life,\u201d says Prof Guy Leschziner, a consultant neurologist who specialises in sleep disorders. \u201cBut it\u2019s also associated with increased risk of cardiovascular disease and stroke. We also know that it impacts a range of other physiological processes, like your immune system, your respiratory system and so on. It even influences how your brain processes pain signals, and makes you more vulnerable to them. <\/p>\n

\u201cEvery single system is influenced by sleep in some way,\u201d he says.<\/p>\n

The good news? Just because you aren\u2019t getting the commonly recommended seven to eight hours doesn\u2019t necessarily mean you\u2019re at risk. Those numbers are typically based on studies from the UK Biobank, a long-term biomedical database that follows the lives of half a million volunteers to investigate how genetics, lifestyle and environment intersect to cause disease \u2013 but that doesn\u2019t mean they\u2019re perfect. \u201cI\u2019m a huge fan of the Biobank, but sometimes it\u2019s difficult to unpick sleep from other causes \u2013 like the fatigue caused by other illnesses,\u201d says Foster. \u201cWith something like sleep, you can\u2019t just slap an average on it and say that\u2019s what everyone should get.\u201d<\/p>\n

So how do you know if you\u2019re getting enough sleep for your health? Perhaps surprisingly, the best marker is whether you feel OK on the amount you get. \u201cThere are some people who need shorter sleep than others in order to maintain the same level of cognitive, psychological and physiological health, and then there are others who are genetically long sleepers who need much more,\u201d says Leschziner. \u201cIf someone\u2019s only sleeping for six hours a night but they\u2019re not tired, they don\u2019t have any cognitive symptoms, and, when given the opportunity to sleep more, they don\u2019t, then that\u2019s a good indicator that you have an underlying genetic short sleep time.\u201d<\/p>\n

The tired brain has a tendency to remember negative experiences, but forget positive ones<\/p>\n

\u2014 \u00a0Prof Russell Foster<\/p>\n

A bad indicator is that you\u2019re irritable, feeling flat, or overreliant on caffeine, says Foster. \u201cThere\u2019s some really beautiful data on the fact that the tired brain has a tendency to remember negative experiences, but forget positive ones,\u201d he says. \u201cSo if you find that you\u2019re depressed and you\u2019re taking a sort of a negative view of the world, that might be an indication you\u2019re not getting one of the most important things for your health. It\u2019s also important to listen to friends, family and colleagues about the way you\u2019re behaving \u2013 and of course, if you\u2019re tired and irritable, you\u2019re going to be less inclined to do that. If you\u2019re drinking excess caffeine to fuel the day, that\u2019s really important \u2013 especially if you\u2019re delaying sleep onset by drinking it into the afternoon and then using alcohol as a sedative, because sedation isn\u2019t as restorative as real sleep.\u201d<\/p>\n

This might be a good time to clarify that insomnia, or being unable to sleep despite wanting to, is a different physiological condition from chronic sleep deprivation, or what happens when you\u2019re burning the candle at both ends.<\/p>\n

\u201cThe easiest way to see the difference is that if you take somebody who is sleep deprived and you give them a bed during the day, they will fall asleep, whereas people with insomnia won\u2019t,\u201d says Leschziner. \u201cWe also know that insomnia and being sleep deprived can have very different impacts on general health. Chronic sleep deprivation is not very good for a range of aspects of your health, whereas for most people with insomnia, a lot of the long-term health effects we associate it with are not necessarily applicable.\u201d<\/p>\n

[\u00a0How much sleep do we need?Opens in new window<\/a>\u00a0]<\/p>\n

One reason for this is that when researchers track the sleep of people with insomnia, their sleep typically isn\u2019t as short as they think \u2013 this is because of a phenomenon called sleep state misperception, where people perceive themselves to have been awake when they\u2019ve actually been asleep. \u201cFor the majority of individuals who complain of insomnia, their total sleep time, when we measure it based on their brainwaves, is not that much shorter than the average person,\u201d says Leschziner. \u201cAnd so while these individuals feel sleep deprived, in most cases they\u2019re not at that much risk of some of the harms that are associated with sleep deprivation.\u201d<\/p>\n

This brings us to the shorter term. Here, the news is slightly better \u2013 though you should still aim to get to bed early rather than burn the midnight oil. \u201cThe current thinking is that memory consolidation seems to happen during slow-wave, or NREM sleep, which dominates the early part of the night \u2013 REM sleep is much more about emotional processing,\u201d says Foster. <\/p>\n

It\u2019s also a good idea to focus on sleep if you\u2019re working on a difficult problem: in a landmark study published in the journal Nature, volunteers working on a complex mathematical task were able to solve it about 60 per cent of the time after a good night\u2019s sleep \u2013 compared with groups that remained awake during the day or were sleep deprived at night, who saw a 20 per cent success rate. \u201cThose results tell you that sleep is enormously important for coming up with novel solutions to difficult problems,\u201d says Foster. \u201cIt\u2019s really not an indulgence.\u201d<\/p>\n

\u201cTo have a single bad night\u2019s sleep is something that we\u2019ve evolved to do every so often, and the brain has an enormous capacity to compensate for it,\u201d says Leschziner. \u201cNow, obviously, our vigilance declines, and it is a physiologically stressful experience. You might be stressed and more irritable, but in the greater scheme of things, it\u2019s not going to make a huge amount of difference to our health.\u201d<\/p>\n

\"OneOne clear takeaway is to try not to overstress about a single night\u2019s bad sleep. Photograph: Roos Koole\/ Getty Images <\/p>\n

Can you catch up over the weekend? \u201cIf you\u2019re oversleeping when you don\u2019t set an alarm, that\u2019s a key sign that you need more sleep, and catch-up sleep is certainly helpful \u2013 there\u2019s no question about that,\u201d says Foster. \u201cBut it has the downside that if you sleep through the morning light, you\u2019ve lost a key signal that is stabilising your internal clock, which means you\u2019re likely to drift into later sleep patterns.\u201d<\/p>\n

Apart from making it more difficult to get up on Monday morning, this tends to destabilise your circadian rhythms. In the short term, it doesn\u2019t really matter what time you get up \u2013 but if you do it repeatedly over a long period of time it can come with health consequences. In shift workers, the problem gets worse \u2013 if sleep gets destabilised then activating the body\u2019s stress response can be the best way to stay awake, but that can come at the expense of the body\u2019s other systems. \u201cIt\u2019s a bit like the gears of an engine,\u201d says Foster. \u201cFirst gear can be fantastic \u2013 it gives you that acceleration you need \u2013 but if you keep your engine there you\u2019ll ruin it. In the same way, constantly elevating the stress response means you\u2019re going to have a suppressed immune system.\u201d<\/p>\n

Sleep is enormously important for coming up with novel solutions to difficult problems<\/p>\n

\u2014 \u00a0Prof Russell Foster<\/p>\n

One clear takeaway is to try not to overstress about a single night\u2019s bad sleep: even if it leads to a couple more nights of tossing and turning, it\u2019s unlikely to do you much lasting damage. But what about when we\u2019re being deprived of sleep for the slightly longer term \u2013 like in the months after we welcome a baby into the house?<\/p>\n

\u201cThis is a question I\u2019m often asked,\u201d says Leschziner. \u201cAnd the honest answer is we don\u2019t know, but what we do know is that parenthood is associated with longevity and with better cognitive health later on in life \u2013 so it seems that if there is a neurological harm attributable to the sleep deprivation of parenthood, then it\u2019s typically offset by other benefits that parenthood provides. One of the theories as to why that might be the case is because having children enriches our cognitive world and increases our cognitive reserve: and so parenthood might actually be protective of brain health.\u201d<\/p>\n

Really, the best advice is to prioritise sleep: recognise that it\u2019s important, make sure you\u2019re setting enough time aside to get as much as you need to feel well rested, and make the most adjustments you can to your current sleep environment. \u201cIf I only did one thing, it would be invest in proper blackout curtains,\u201d says Leschziner. \u201cAnd if you live in a noisy environment, then consider comfortable earplugs that are designed for sleeping in.\u201d<\/p>\n

Finally, there\u2019s at least one good reason to stay up late, even if you shouldn\u2019t make a habit of it. \u201cWhat some people find is that they can access their executive mode network \u2013 which is the set of brain regions that keep us laser-focused \u2013 by working late at night, and just ploughing through a project,\u201d says Foster. \u201cSo the occasional all-nighter, if you\u2019re doing something that\u2019s highly task-oriented, can be helpful. But don\u2019t do it if you\u2019ve got a difficult social interaction to deal with or you\u2019re driving the next day.\u201d – The Guardian<\/p>\n","protected":false},"excerpt":{"rendered":"\u201cOnce, after I did a presentation, someone came up to me and said, \u2018I don\u2019t get eight hours…\n","protected":false},"author":2,"featured_media":374143,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[103,12875,61,60,2686,27599],"class_list":{"0":"post-374142","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-health","8":"tag-health","9":"tag-health-wellness","10":"tag-ie","11":"tag-ireland","12":"tag-sleep","13":"tag-university-of-oxford"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/374142","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=374142"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/374142\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/374143"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=374142"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=374142"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=374142"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}