We’ve all heard that it’s important to get 7 to 9 hours of sleep each night. This recommendation is repeated so often that it has become gospel. Low intake increases the likelihood of poor health conditions in the short and long term, including memory loss, metabolic problems, depression, dementia, heart disease, and weakened immune systems.
But in recent years, scientists have discovered a rare breed that consistently rarely closes its eyes and doesn’t suffer from wear and tear.
People who are born short sleepers are genetically hardwired to need only 4 to 6 hours of sleep a night. These outliers suggest that quality, not quantity, is important. If scientists can figure out how these people behave differently, they hope they may gain insight into the nature of sleep itself.
About supporting science journalism
If you enjoyed this article, please consider supporting our award-winning journalism. Currently subscribing. By subscribing, you help ensure future generations of influential stories about the discoveries and ideas that shape the world today.
“The bottom line is that we don’t understand what sleep is, much less what it’s for, given that the average person spends a third of their life sleeping. That’s pretty incredible,” says Louis Ptaek, a neurologist at the University of California, San Francisco.
Scientists once thought that sleep was just a period of rest, like turning off your computer in preparation for the next day’s work. Thomas Edison claimed to never sleep more than four hours a night, calling sleep a waste of time and a “relic of the cave days.” His invention of the incandescent light bulb helped others sleep less. Today, historically more American adults are getting less than 5 hours of sleep.
However, modern sleep research shows that sleep is an active and complex process, one that we don’t necessarily want to shorten. Scientists believe that while we sleep, our bodies and brains replenish energy stores, eliminate waste and toxins, prune synapses, and consolidate memories. As a result, chronic sleep deprivation can have serious health implications.
Most of what we know about sleep and sleep deprivation comes from a model proposed in the 1970s by a Hungarian-Swiss researcher named Alexander Borbély. His two-process model of sleep explains how separate systems, circadian rhythm and sleep homeostasis, interact to control the time and length of sleep. The circadian clock determines the 24-hour cycle of sleep and wakefulness based on external cues such as light and darkness. Sleep homeostasis, on the other hand, is driven by internal pressure that increases while awake and decreases during sleep, ebbing and flowing like hunger.
There are variations to these patterns. “We’ve known for a while that there are morning owls and night owls, but most people fall somewhere in between. We’ve long known that there are short sleepers and long sleepers, but Most people are somewhere in between,” says Ptaek.. “They were active, but the reason they weren’t recognized is because these people generally don’t go to the doctor.”
That all changed when Ptaek and his colleague Ying Hui Fu, a human geneticist and neuroscientist at the University of California, San Francisco, were introduced to a woman who felt that early to bed and early to rise was a curse. The woman woke up naturally in the early morning when it was “cold, dark, and lonely.” Her granddaughters have inherited the same sleep habits as her. Researchers pinpointed the genetic mutation in this rare type of morning lark, and after publishing their results, thousands of super early risers emerged.
But Fu recalls being intrigued by one family that didn’t fit that pattern. Although these families woke up early, they did not go to bed early and felt refreshed after only about 6 hours of sleep. They were the first people to be identified with familial natural short sleep duration, a condition that runs in families like other genetic traits. Fu and Ptaek explain the cause of their short sleep. December 2nd.
“Whatever your body needs when it comes to sleep, it can get it done in a short amount of time.” —Yin Hui Fu, human geneticist and neuroscientist
Researchers continued to manipulate genes. December 2nd Mutations into mice show that this animal requires less sleep than its littermates. They discovered that one of the functions of this gene is to help control the levels of a hormone in the brain called orexin, which promotes wakefulness. Interestingly, orexin deficiency is the main cause of narcolepsy, a sleep disorder characterized by episodes of excessive daytime sleepiness. However, orexin production appears to be increased in people who sleep less.
Over time, the research team identified seven genes associated with naturally short sleep. In one family with three generations of short sleepers, researchers found that ADRB1It is highly active in the dorsal pons, an area of the brainstem involved in regulating sleep. When scientists used a technique that stimulated areas of the mice’s brains to wake them from sleep, the mice ADRB1 The mutation woke up more easily and stayed awake longer.
Researchers identified another gene mutation in a father-son pair of short sleepers. NPSR1involved in regulating the sleep/wake cycle.. When they created mice with the same mutation, behavioral tests showed that they slept for less time and lacked the memory impairments typically associated with short nighttime sleep.
The research team also discovered two different mutations in a gene called . GRM1two unrelated families with shortened sleep cycles. Again, mice incorporating these mutations slept less and had no apparent health effects.
Similar to mice, people who are naturally short sleepers don’t seem to suffer from the negative effects of sleep deprivation. If anything, they’re doing very well. Research has shown that such people are ambitious, energetic, and optimistic, and have significant resilience to stress and a high pain threshold. They may live even longer.
Based on the findings on short sleepers, some researchers believe it may be time to update the old two-process model of sleep. This is how Ptahek developed the idea of third influence. The updated model may be deployed as follows: In the morning, your circadian clock tells you it’s time to start your day, and your sleep homeostasis tells you you’ve had enough sleep to get out of bed. And the third element, the behavioral drive, forces us to go out and do work, find mates, gather food, and so on. At night, this process reverses and calms your body for sleep.
Perhaps short sleepers are motivated enough to overcome the innate processes that keep others in bed.. But somehow short sleepers’ brains are wired to sleep so efficiently that they may be able to do more with less time.
efficient sleep
“There’s nothing magical about seven to eight hours,” says Phyllis Gee, director of the Center for Circadian Sleep Medicine at Northwestern University near Chicago. Gee can imagine countless ways to make short sleeper brains more efficient. Do they have more slow-wave sleep, the most restorative sleep stage? They produce more cerebrospinal fluid, the fluid that fills the brain and spinal cord, and are able to remove more waste products. Is it because our metabolic rates are different that we fall asleep faster?
“It’s all about efficiency, sleep efficiency, that’s how I feel,” Fu says. “Whatever your body needs when it comes to sleep, it can get it done in a short amount of time.”
A recent study by Fu and Ptáček found that people who naturally sleep less may be more effective at clearing harmful brain aggregates that contribute to neurodegenerative diseases such as Alzheimer’s disease. It is suggested. Researchers crossed mice with a gene for short sleep times with mice that carry a gene that predisposes them to Alzheimer’s disease. Mice with Alzheimer’s disease accumulated abnormal proteins (amyloid plaques and tau tangles) that are hallmarks of dementia in humans. However, the brains of the hybrid mice rarely developed such tangles or plaques, as if the sleep mutation protected the animals.
Fu believes similar studies in models of heart disease, diabetes, or other diseases associated with sleep deprivation would yield similar results.
Deeper secrets of sleep
It is not yet clear how the short sleeper genes identified so far protect people from the negative effects of sleep deprivation, or how mutations in these genes increase sleep efficiency. To find the answer, Fu and Ptáček brought short sleepers to a joint laboratory and began measuring their brain waves while they slept. Their sleep research was derailed by the pandemic, but they’re eager to get it back on track.
Researchers are also interested in understanding other sleep abnormalities. Sleep duration, like most behaviors, follows a bell curve. Short sleepers sit on one end of the curve, long sleepers on the other side. Dr. Hu has discovered one genetic variant associated with long sleep times, but it is difficult to study because long sleepers’ schedules do not match society’s norms and demands. People who sleep long hours are often forced to wake up early to go to school or work, which can lead to sleep deprivation, which can lead to depression and other illnesses.
However, although sleep has great power, It can be formed not only by genetic factors, but also by the environment. Knowing that better sleep is possible and understanding its fundamentals can point the way to interventions to optimize sleep, allowing more people to live longer, healthier lives. It will look like this.
For example, Gee’s lab has devised the use of acoustic stimulation to promote slow waves of deep sleep that enhance memory processing, and this may be one of the secrets to short sleepers’ success. There is. One study played pink noise (a sound similar to rain or the ocean, softer and more natural than white noise) while study participants slept. The next day, participants remembered even more in a test in which they had to learn and recall word pairs. “You can improve your memory, but it doesn’t make you sleep longer or necessarily less,” Gee says. “I think there is still a lot to learn.”
For now, researchers recommend recognizing that sleep times vary from person to person and focusing on getting the amount of sleep you need. Ptaek still cringes when he hears someone preach that everyone should get eight hours of sleep every night. “That’s like saying everyone in the country has to be 5 feet 10 inches,” he says. “Genetics doesn’t work that way.”
This article was first published Magazines you should knowan independent journalism initiative from Annual Reviews. Sign up for our newsletter.
