We somehow seem to be at war with sleep. And we have been, for a long time.
Remember how, as a kid, going to bed felt almost like punishment? But we’re now more mature as grown-up adults – right? Nowadays we do things like get to work early and read articles with titles like ‘Successful People Do These 17 Things Before 5.’
According to Maslow's hierarchy, sleep is considered to be a basic human need and is therefore on par with eating, drinking and sex. So why do we feel the need to mess around with it so much? And what does our body, as the only one who really matters here, have to say about it?
To put a stop to all this worrying and save us – as well as you – from sleepless nights, we’ve taken a closer look at what the science has to say on the subject so that we can give you an arsenal of facts for your own personal truce.
The benchmarks: How much sleep does an adult need?
How much sleep you need depends first on your age. Newborns, for example, sleep up to twice as long as adults.
The US National Sleep Foundation, one of the top authorities on sleep, provides the following recommendations on sleep length:
- Newborn: 14 to 17 hours
- Babies: 12 to 15 hours
- Infants: 11 to 14 hours
- Pre-school children: 10 to 13 hours
- School-age children: 9 to 11 hours
- Teen: 8 to 10 hours
- Young and middle-aged adults: 7 to 9 hours
- Elderly people: 7 to 8 hours
One thing seems fairly certain: The amount of sleep we need decreases as we age.
At the same time, this information is only broadly applicable. So if you don’t see yourself reflected in these numbers, don’t worry about it. After all, these are average values, and even the researchers see certain deviations to be entirely normal.
Is too much sleep unhealthy?
Can you get too much of a good thing? When it comes to sleep, there's a lot to suggest that this is indeed the case, at least according to a large-scale Spanish study. In fact, if you sleep 9 hours or longer on a regular basis, you could be at increased risk of developing dementia later, the researchers said.
In addition, studies (here and here) show subjects who sleep longer than usual have increased CRP levels, which indicates inflammation in the body.
Getting too much sleep can also have a paradoxical side effect: Instead of jumping out of bed rested and fit, you may feel lethargic and tired after 10 or 11 hours of sleep. Your sleep quality might also not be as good as it would be with 8 hours of sleep.
So it’s best not to overdo it with your nighttime rest. And let's face it – in the end, life is just far too exciting to spend so much time asleep.
But does this mean you need to go to the other extreme and turn your night into day?
How little sleep is too little?
We all need a certain amount of sleep, that much is clear. The right amount of sleep makes you not only more alert and healthy, but it can also make you feel better.
However, if you get well below the recommended limit of 7 hours of nighttime rest, you are either cheating yourself out of valuable sleep or suffering from a rare mutation: Researchers have found mutations in the pithily titled protein hDEC2-P385R in people who need very little sleep. This, in turn, affects DNA transcription.
If you have this gene mutation, you’ve probably noticed it in your parents or grandparents, as it is inherited. The study, examining a family in which the mutation was present, found that those who were short sleepers got by on 6.25 hours of sleep in the long run, while the rest of the family spent around 8 hours in bed.
Too much or too little sleep? Why neither is a good idea
As for the effects of your sleep length, some studies show a U-shaped curve in their findings.
All that means is that too little sleep is associated with a longer list of negative effects while a healthy dose of sleep shrinks the list, and once you start sleeping too much over a longer period of time, the list starts growing again.
A study of over 5,000 participants found that both types of sleep can affect your mental performance. And another study suggests that too little sleep – as well as too much – may be linked to chronic depression and anxiety disorders.
Our bodies are not immune to the impact of sleep behaviour that deviates from the norm. Take, for example, the results of a Canadian study that monitored nearly 280 short and long sleepers over a six-year period. Compared to ‘normal’ sleepers, participants in both groups had more than a 20 percent higher risk of developing obesity.
Sleep deprivation can be a good thing
Pulling an all-nighter once in awhile isn’t necessarily a bad thing. In fact, science has long proved what you probably can appreciate from your experience with the occasional dance-through-the-night party: A night without sleep can lead to a short-term improvement in symptoms of depression.
That fact that sleep deprivation could prove helpful in depression was documented as early as 1818 by Johann Christian August Heinroth in his book titled ‘Textbook of Disturbances of Mental Life or Disturbances of the Soul and their Treatment’. Though it sounds like a book authored by a professor at Hogwarts, Heinroth was in fact the first-ever professor of psychiatry as a psychotherapist.
Today, the concept of therapeutic sleep deprivation, referred to as ‘Wake Therapy’, is backed up by recent studies that suggest an improvement in depression symptoms in about 40 to 60 percent of cases .
The mechanisms at work here are, however, still unclear. For some, the boost lasts only until the next sleep cycle while, for others, it remains palpable for a few weeks. Drug treatment often accompanies this kind of therapy.
How long can we go without sleep?
In 1964, 17-year-old high school student Randy Gardner set out to answer this question. To be clear: This is not something we recommend you try out yourself. Managing to stay awake for a whopping 11 days and 25 minutes, he ended up hallucinating and found his physical and mental performance to be severely impaired.
In 2007, a Brit added another 2 hours to his personal experiment with the same issue. By then, however, due to safety issues, the category had long been removed from the Guinness Book of World Records, so Gardner continues to hold the unchallenged record.
You’d think that Gardner would have slept for an entire week after the whole ordeal. But he actually only slept for one long night, for 15 hours. After that, his sleep length returned to its 7 to 8 hour span. To this day, this example serves as evidence for the fact that we are limited in catching up on our night's rest.
The good news is, however, that sleep deprivation is usually not fatal. Though this is not the case with ‘lethal familial insomnia’ – an extremely rare neurodegenerative disorder. This inherited genetic defect occurs primarily in middle-aged to older adults and leads to death within years, sometimes months.
Can you catch up on lost sleep?
Perhaps you recall Momo and the Men in Grey, who robbed people of time with their time bank. Though this makes for a good tale, when it comes to our sleep, there’s a similar story at work. In fact, you probably have some experience with sleep banking.
The idea here is, just as with money, we vary from day to day a bit on how sensible we are with our time. It's only when we let things get out of hand that we go into the red. And just like the red numbers recorded on our bank account, our bodies register a sleep debt.
So when you don't get enough sleep over an extended period of time and feel an ever-increasing need to make up for that time, you are ‘going into sleep debt.’ You've essentially overdrawn your time account – taken time where there was none, when you should have been asleep.
So what’s the good news? You can’t really make up for your sleep debt. Because your body is much more compliant than your schedule, you don't have to sleep for the exact amount of hours (or even longer) that you've lost.
And even if you wanted to, you probably couldn't. Even Gardner didn’t sleep 11 days after his experiment, he slept ‘only’ a paltry 15 hours. If you've been neglecting your sleep, you don't necessarily have to set aside an entire weekend for sleep alone.
And what’s the bad news? You can’t really make up for your sleep debt. Deficits accumulated over a long period of time can have a negative impact on your health, and there’s not much you can do about it after the fact.
Much like your diet, though, there's not much point in engaging in ex post worrying. If you ate fast food all day yesterday, you can't ‘make up for it’ today. You can, however, be mindful of the fact – and do better from now on, starting today.
Sleep your way to the top!
So what’s ‘right’ for you now? With an exception here and there, you should settle in somewhere between 7 and 9 hours. To get a more precise idea of your optimal sleep length, check out our article on the sleep calculator.
By the way, if you’re a notorious sleep debtor, you’re not alone.
In a 2001 interview, Bill Clinton once said: “Every major mistake I've made in my life, I've made because I was too tired.”
Arianna Huffington at the Huffington Post admitted to having taken things a bit too far when she collapsed at her desk from exhaustion and a lack of sleep, only to wake up in a pool of blood with a broken cheekbone.
Declaring war on our culture of sleep predation, she speaks frequently on advising others how to ‘sleep their way to the top’.
She also wrote the following quote, which we would like to share with you:
‘I've made the worst decisions in life when I haven't had enough sleep. When you’re tired, you end up hiring the wrong people and marrying the wrong person.’
Now if that’s not sound advice for a lifetime, I don’t know what is! Here’s to a good night!