Ōtautahi - Some people are gifted with genes that pack the benefits of sleep into an efficient time window, keeping them peppy on only four or six hours of sleep a night, according to UC San Francisco research.

Their scientists says these elite sleepers show psychological resilience and resistance to neuro-degenerative conditions that may point the way to fending off neurological disease.

There's a dogma in the field that everyone needs eight hours of sleep, but the study confirms the amount of sleep people need differs based on genetics.

Think of it as analogous to height; there's no perfect amount of height, each person is different. We've shown that the case is similar for sleep.

For over a decade,  the San Francisco researchers been studying people  with the ability to function fully on, and have a preference for, four to six hours of sleep a night.

They've shown that it runs in families and, so far have identified five genes across the genome that play a role in enabling this efficient sleep. There are still many more genes to find, the researchers say.

The brain accomplishes its sleep tasks in a shorter time and less time spent sleeping efficiently may not equate to a lack of sleep.

The researchers say similar investigations would show the efficient-sleep genes conferring comparable protections and improving peoples' sleep could delay progression of disease across a whole spectrum of conditions.

Sleep problems are common in all diseases of the brain. This makes sense because sleep is a complex activity. Many parts of your brain have to work together for people to fall asleep and to wake up. When these parts of the brain are damaged, it makes it harder to sleep or get quality sleep.

Understanding the biological underpinnings of sleep regulation could identify drugs that will help ward off problems with sleep disorders. In addition, improving sleep in healthy people may sustain wellbeing and improve the quality of time we each have, the researchers say.

But pursuing the many genes involved is a long game that they liken to putting together a thousand-piece jigsaw puzzle.