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Here's Why You Need Quality Sleep

For starters, a lack of it could be killing us.

Most of us spend about a third of our lives sleeping. We wonder if we could do with less; after all, modern life already gets in the way. The Russian author Vladimir Nabokov called sleep a "moronic fraternity" and a "nightly betrayal of reason, humanity, genius". He was also an insomniac and suffered from various ailments – an unfavourable outcome of inadequate sleep, perhaps?

“When we are sleeping, our bodies are working very hard to perform all kinds of maintenance tasks for us so that we can stay healthy and live a long life,” explains Dr Ying-Hui Fu, Professor of Neurology at University of California, San Francisco. “If you don’t get good sleep, the consequences are predictable.”


The neuroscientist, who says we cannot live without sleep nor live well without quality sleep, tells us why it is fundamental to human life.

Your brain is still awake whilst you snooze

The question of what constitutes sleep is so complicated that scientists are still trying to define the reasons. Why we require such long hours of slumber, for instance, remains a mystery.

But what research has shown: the mind and body does not shut down when we're sleeping, and sleep has critical functions we need for optimal health, including facilitating cellular recovery and cognitive function, and removing toxins that accumulate during wakefulness. Past studies have shown that levels of amyloid beta, a protein linked to Alzheimer’s disease, drop during sleep and rise once we wake.

The penalties of insufficient rest

It goes beyond nodding off during the day. Sleep affects almost every type of tissue and system in the body so it shouldn't come as any surprise that the price of inadequate sleep may be poor health.

Research after research has revealed that a lack of sleep depresses various functions; amongst them reducing our cognitive and memory powers, to a similar degree as alcohol intoxication. It can cause weight gain, as a result of altered levels of appetite-regulating hormones.

The human body also relies on sleep to help with our immune system. Sleep deprivation weakens it and increases our susceptibility to infection. It’s linked to inflammation, which may explain why people who are chronically sleep deprived have a higher risk of diabetes, cardiovascular disorders, cancer and Alzheimer's disease.


How much sleep does one really need?

The general consensus amongst experts is that adults need 7-9 hours of sleep. But it's not a one-size-fits-all.


Our sleep schedule changes with age. Teenagers and people in their early 20s for instance, tend to be night owls; this is largely caused by hormones. Your genes play a part too. They influence our circadian rhythms and timing of sleep, and are also involved in sleep disorders. If you're wondering why all that chamomile tea isn't working, well, that's one possible reason.


“Under the assumption that you have no other health issues, if and when you get enough sleep, you should feel great. You should not need much caffeine or other stimulants to help you stay awake.”

"Only you can figure how much sleep you need," Dr Fu says, adding that you can find out by

following your body's schedule carefully. The best time to do this is when you’re on holiday, and can go to bed and wake up whenever your body wants to.


There’s a catch: if you’ve got significant sleep debt and already have related health issues, this won’t work. Instead, consult a sleep clinician.

Some people thrive on less sleep (it’s likely you’re not one of them)

There are larks and owls, and there are "natural short sleepers". They routinely get 4-6 hours of sleep but wake up feeling refreshed. These individuals are not insomniacs, who tend to be tired all the time. Once again, it's down to DNA – more specifically, a genetic mutation. Dr Fu, who led the teams that identified this short sleep gene, describes this group as "optimistic and very active."

"They're usually excellent multitaskers, and have no jet-leg problems when they travel," she says. "A lot of them but not all don’t feel pain easily, have unusually good memory and seem to have long health spans."


Unfortunately, you can’t train yourself to become one. The mutation is exceedingly rare, occurring in fewer than one in 4 million people.

Dr Fu’s tips for sound slumber

Yes, you know it it involves LED-emitting devices i.e. your mobile phone.

  1. Make sure to be in a comfortable, quiet and dark place.

  2. Use ear-plugs or eye-covers to help, if necessary. She uses both of them.

  3. No caffeine hours before bed.

  4. Avoid stimulating activities before you hit the sack.



This article was supplemented with content from Dr Fu's book, Sleep To Thrive: The Everyday Secret to Successful Aging.


Ying-Hui Fu, Ph.D. is a Professor of Neurology at University of California San Francisco and a pioneer in the study of sleep and genetics. She led the research teams that discovered short-sleep genes, and has published more than 100 high impact scientific papers over more than three decades of research. Learn more about her work at scienceofsleep.org