The secret of people who can function well on only a few hours of sleep

From a very young age we’re taught how important sleeping enough hours is for us to properly function during the day, with a general rule that eight hours per night is ideal. 

As we get older, our commitments multiply and the burden of life increases, and then we try to at least reach the minimum threshold of six hours of sleep a night.

There are many studies that show how sleeping less than a minimum of six hours might damage our health and quality of life in a variety of ways, from difficulty concentrating to affecting hunger cues and metabolic mechanisms to shortening life expectancy and increasing risk of serious medical conditions such as stroke and dementia. 

Yet, there are people who can function really well even with less than six hours of sleep, without suffering consequences such as fatigue, drowsiness and lack of concentration during the day. 

Who are they and what do they know that we don’t?

People with short sleep syndrome can sleep four-six hours a night and still function flawlessly. This isn’t a very common syndrome; it’s estimated that only 1% of the population have it, but some people who claim to belong to this group are probably very familiar to you: Former US President Barack Obama, the mythical lifestyle priest Martha Stewart and Jack Dorsey, the man who established Twitter.

Although a high percentage of people report that they routinely settle for a night sleep of less than six hours, only a few of them actually have short sleep syndrome, at least clinically. The reason is that not everyone who is used to sleeping less than six hours is really functioning at their best the next day.

Dr. Paula G. Williams, a professor of clinical psychology at the University of Utah, a prime researcher of this syndrome, says she has identified several other characteristics of people with the syndrome, which may help determine whether it’s really short sleep syndrome or just unsatisfactory sleeping habits.

As mentioned, the main symptom that characterizes the syndrome is people who regularly and consistently sleep less than six hours a night yet don’t suffer from any decrease in function during the day and feel completely fresh from their short nightly rest. 

In addition, according to Williams, "they are characterized by hypomania, impulsivity and a higher-than-average reward threshold. They also tend to take part in activities with a high stimulus level, which helps them overcome fatigue or drowsiness."

Dr. Williams explained that short sleep syndrome is very different from other sleep disorders such as insomnia. For example, people with insomnia will also suffer from high levels of anxiety: "People with insomnia often report fatigue, lack of freshness and lack of satisfaction from a short sleep cycle,” she said.

Short sleep has been their normal sleeping pattern for most of their lives, from childhood or adolescence and it characterizes their night's sleep even when they break routine (weekends or vacations, for example), when people generally sleep later.

They don’t need something, such as a white noise machine, to fall asleep. They naturally fall asleep at around the same time every night, sleep six hours or less, and get up at a set time every day, relaxed and refreshed.

People with short sleep syndrome usually tend to sleep for a fixed number of consecutive hours. This is in contrast to sufferers of other sleep disorders who often report waking up at intervals during the night, and so they feel fatigued even when they first get up in the morning.

The process of diagnosing the syndrome will begin with the family doctor, who will ask about sleeping habits and ease of falling asleep as well as additional lifestyle characteristics. Later, the patient may be required to record sleep activity over a two-week period, and be monitored in a special sleep lab that includes watching brain activity in sleep as well as recording other physical cues.

What causes short sleep syndrome?

Not much is known about the causes of short sleep syndrome, but researchers have found some fairly convincing evidence that some causes are genetic. 

Dr. Ying-Hui Fu, a professor of neurology at the University of California San Francisco, is probably the most senior researcher in the field of short sleep syndrome, and has been researching it for 25 years. After a long research period, she has identified what she calls "short sleep genes."

Fu and her team analyzed data from sleep studies and located people with patterns that may be appropriate for short sleep syndrome. 

In DNA tests performed on these people, they identified a number of suspicious genetic mutations and then copied them through genetic engineering to animal models, including laboratory mice and fruit flies. At least three genetic mutations are associated with short sleep syndrome, but don’t replicate, that is, each one individually can cause the syndrome to appear.

How is the syndrome treated?

According to the National Sleep Institute in the United States, short sleep syndrome doesn’t require any special treatment. This is because those who have  it usually don’t suffer from functional impairment due to their short sleep.