I've been having trouble sleeping — for as long as forever. Sometimes it's just a feeling. Other times, it's a fact (I know because my watch tells me). But then my watch may be part of the problem. It's constantly reminding me to get to bed on time and accosting me with poor sleep scores. It drives my anxiety through the roof, my heart races and I feel like I can't sleep. But then I still feel fine the next day. Weird.
"When you're sleep deprived, you have poor judgment," said Catia Reis, a sleep researcher at the University of Lisbon, when we spoke.
That might explain my predicament. Because even when I feel fine during the week, I oversleep at the weekend — which is a sure sign of sleep debt, she said.
Reis has studied a variety of sleep-related conditions, including the effects of jet lag and sleep deprivation among athletes.
One investigation compared levels of sleepiness among patients with sleep apnea — a condition where you stop breathing intermittently through the night — and shift workers, who work against their natural, circadian rhythm. That's our inner clock that tells us when we're wakeful or sleepy.
She compared the results from both subjective assessments made by participants and objective, clinical tests, and found a "mismatch" in people's ability to assess their own levels of sleepiness the more they were exposed to that very thing: sleepiness.
Basically, the brain stops working. And that should be concerning, given that the brain plays a central role in sleep.
Sleep or die
When we sleep, the body performs several restorative functions: It removes toxins we have ingested through food or the atmosphere, generates new energy and is essential for our learning and memory.
"Sleep involves many parts of the brain," said Ying-Hui Fu, a sleep researcher at the University of California San Franscisco. "Almost every disease of the brain, including neurological and psychiatric, [can be linked to] sleep problems."
On average, people need about 7.5-8.5 hours' sleep per night.
But every so often we hear about people in demanding jobs, usually politicians, boasting — or claiming credibility — by saying they rarely sleep more than a few hours; like they're ALWAYS WORKING FOR THE PEOPLE.
Most recently, it was Japan's Prime Minister Sanae Takaichi who reminded us she's slept between zero and three hours per night while in office.
As a former heavy metal drummer, you might expect a certain level of stamina from the Japanese PM. But while voluntary, habitual (or trained) sleep deprivation — if that's what it is in Takaichi's case — may be an impressive sleep-work-no-life-balance ethic, it's not a good, long-term strategy.
In the best-case scenario, a long-term "sleep debt" can cause your body to accumulate toxins, risking heart or brain disease. In the worst-case scenario, it can be fatal.
"There are only two things more important than sleep for our total health," Fu told DW. "One is air. If we don't have air, we die in a few minutes. The other is water. If we don't have water, we die in a few days. If you don't eat, you can live a couple of months. But if you don't sleep, you can probably only live for a couple of weeks."
And that goes for all animals — "if we don't sleep, we die," she said.
The exception: natural short sleepers
Natural short sleepers are the exception to the rule. They can sleep fewer than six hours per night and not only feel fine, but also actually are fine — healthy, happy and energetic. They appear to have genetic variations that allow them to thrive. Fu cited an 80-year-old Natural Short Sleeper who competed in triathlons.
Fu and her lab found the first of these variations in the gene DEC2 and published their findings in 2009. Ten years later, they published a paper suggesting that the gene ADRB1 was also linked to Natural Short Sleeper Syndrome. Findings into the genes NPSR1, GRM1, SIK3 followed, and there are others in the pipeline.
We're calling them gene "variations" rather than "mutations" because mutations are often associated with negative health effects. But it appears that Natural Short Sleep does not risk the health issues that habitual short sleepers or sleep deprived people face.
The genes show a range of functions that sleep effects:
- DEC2: helps regulate sleep/wake duration
- ADRB1: mediates cardiac and neuronal signaling
- NPSR1: helps modulate arousal and anxiety
- GRM1: involved in brain function; may be linked to depression
- SIK3: plays a role in cell cycle-, metabolic and inflammatory- regulation
Each has taken years of painstaking basic — foundational — research to find and test.
"Every one of us has between 500 to 1,000 unique mutations in our genome. To know which one is causal is very difficult," said Fu.
The impact of better sleep on humanity
The number of known Natural Short Sleepers is small, but Fu says Short Sleeper Syndrome is likely to be more common than research currently suggests.
Most of Fu's findings are limited families that share a gene variation. That's been for a practical, methodological reason: If three members of a family have the same variation and they all appear to be healthy on only four to six hours' sleep, then that gene variation may well be responsible, especially if it's in a gene that is known to be important for healthy sleep function. But it's early days.
"We just know that they perform better and they're healthier. And the most logical explanation for me is that their sleep function is better," said Fu.
Reis is also cautious about the state of research in this area, saying there are still too few studies into Natural Short Sleepers.
"When objectively test [Habitual Short Sleepers] and we expand their sleep, we know they improve," said Reis. "But the problem is we don't have enough longitudinal studies with [Natural Short Sleepers]."
Fu would agree. But she said it was a struggle to get the research financed.
"My goal is to help everybody get good sleep. Because if we can help everybody get good sleep, all diseases will drop," said Fu. "The entire spectrum of disease incidence would drop. Can you imagine the impact on humanity?"
Edited by: Carla Bleiker