A Good Night's Sleep Is More Important for Your Health Than You Thought

How many hours do you sleep at night? Most of us would answer this question with two somewhat frustrating words: "Not enough." Indeed, the demanding pace of life pushes many of us to sleep less than we truly need. But is it really that bad? How much does lack of sleep affect us?

A lot, it seems. Recently, Professor Matt Walker, a neuroscientist and psychologist from the University of California, Berkeley, gave a comprehensive TED talk where he detailed not just the benefits of sleep, but also the damage caused by lack of it.

According to him, human cognitive development appears like a bell curve. Early in life, we have only basic abilities, which develop rapidly in the first few years. Later, the development slows, and eventually, abilities begin to decline. In old age, brain cell renewal occurs at a slower rate than the breakdown of dead brain cells, leading to cognitive decline. While it cannot be completely prevented, it can be slowed and made less aggressive in various ways.

One of the most effective ways, according to Professor Walker, is to maintain healthy sleep patterns. He states that even a minor reduction in sleep can cause not only health issues but cognitive damage as well. Researchers found significant negative effects on participants who slept 5 hours a night compared to those who slept 7 hours. Just a two-hour difference, but drastic effects. The greatest impact of sleep deprivation is on the brain—specifically on memory and other cognitive functions. Professor Walker explained that beyond the known need for sleep after learning to consolidate knowledge in brain cells, it is now known that sleep is also required before learning, so the brain is prepared to absorb new information.

This was proven in an experiment comparing two groups of people—one group slept 8 hours a night, and the other didn’t sleep at all. A learning test conducted afterward, with MRI scans of their brain activity, revealed a 40% drop in the achievements of the group that didn’t sleep! So if you’re a student considering skipping sleep for intensive study the night before an exam—think again.

Night Brain Waves

According to Professor Walker, during stages of deep sleep, there are especially powerful brain waves, which he dubs "sleep spindles." These waves help transfer short-term memories into long-term storage, integrating them into a person’s knowledge base. Memories that don’t undergo this transfer are set to be erased from the short-term memory to make room for new information. Walker’s studies suggest that sleep problems and decreased sleep quality are clear indicators of aging and may significantly contribute to the development of dementia and Alzheimer’s.

Despite other factors causing neurological diseases in older age, most of these factors are fixed and cannot be changed. Sleep, however, can be adjusted. Primarily by ensuring sufficient sleep from a young age and, additionally, through technological developments that are in progress to electrically stimulate brain waves to improve sleep quality in older age.

Between Daylight Saving Time and Car Accidents

In his lecture, Professor Walker explains that the lack of sleep is far more significant than most people believe, stating that even a single hour of sleep reduction causes notable damage. This is surprisingly proven by daylight saving time. According to Walker, each year when the clocks spring forward and an hour of sleep is lost, there’s a marked increase in car accidents, heart attacks, and more.

Indeed, another system significantly affected by our hours of sleep is the immune system. Walker notes that sleeping only four hours a night, for example, can completely collapse the immune system cells whose role is to detect, attack, and destroy foreign agents in the body. The link between sleep problems and the immune system’s functional quality led the World Health Organization to state that shift work is a probable carcinogen because it disrupts the sleep-wake cycle. Yes, it's that significant.

So how many hours should you sleep at night? Professor Walker’s answer is clear: 8 hours. In an experiment he described, a group of people was tested under two sleep conditions: sleeping 6 hours a night for a week and 8 hours a night for a week. The results showed distortion in 711 genes following the week of 6-hour nights. The distortion affected genes related to the immune system, clarifying a significant link between insufficient sleep and the development of chronic inflammation, cardiovascular issues, the formation of body tumors, and more.

How to Sleep Well

In conclusion, Professor Walker detailed the ideal conditions for effective sleep. First, as mentioned, sleep for eight hours a night—no less, but also no more. Second, ensure good quality sleep. Walker offered two tips to help improve sleep quality. The first tip is to maintain a consistent sleep and wake-up time every day—even on weekends. This regularity helps establish sleep and enhances its quality. The second tip is to cool the room. According to Walker, the body needs to lower its temperature by 1-1.5 degrees Celsius to fall asleep and stay asleep, hence why falling asleep in a cool room is easier than in a warm room. The ideal sleep temperature, he says, is 18 degrees Celsius.

And what if you get into bed but keep tossing and turning and can’t fall asleep? Professor Walker unequivocally recommends getting out of bed in such a case, leaving the bedroom, and engaging in some activity until you're tired enough to sleep. The reason is that the brain needs to link the bedroom with actual sleep. Remaining in bed when unable to sleep teaches the brain to associate the bedroom with wakefulness, exacerbating difficulties falling asleep in the future.

So go ahead, get some sleep. Goodnight.