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Healthy Living for Women

Is Sleep Quality or Quantity More Important?

If you've ever wondered how to measure the effectiveness (or restfulness) of a good night's sleep, read this.

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Seven to eight hours of sleep per night: That’s the gold standard that’s been touted for years and years. But, as you’ve likely experienced, eight hours isn’t always feasible — or enough to make you feel like you’re well-rested. And there are plenty of people (you might be one of them!) who can sleep just four or five hours at night and wake up feeling perky and fully refreshed. So, does the quantity of your sleep matter? Or is it the quality that’s more important?

We might finally have an answer to this common question, thanks to new research. A team of researchers at the University of California — San Francisco has spent more than a decade studying sleep habits, patterns and genes in individuals. And their latest study suggests that we might want to rethink how we’ve been setting our nightly sleep goals.

There’s No One Right Way to Sleep

While we’ve always been told that seven to eight hours each night is the key to restful, healthy sleep, the truth is sleep isn’t always so straightforward. While these recommended benchmarks are ideal for some people, sleep is really more personalized — and the right approach differs from individual to individual.  

For example, some are able to enjoy deeply restorative and restful sleep even if they only get a total of four to six hours nightly. Others, however, need longer than the recommended eight hours to wake up feeling well-rested. And who hasn’t woken up from poor-quality sleep only to feel more exhausted?

In a new study, researchers share more than 10 years of data on how different sleep patterns affect different individuals. And their findings suggest that not only is eight hours of sleep not the best recommendation for everyone, but sleep needs also vary from person to person.

Over years, the researchers studied individuals who live with Familial Natural Short Sleep (FNSS), or the ability to fully function on four to six hours of sleep nightly as “efficient” sleepers. FNSS has been found to run in families, and there are five key genes that individuals with FNSS exhibit. In their latest study, they tested the hypothesis that these efficient sleepers may be better protected against neurodegenerative diseases — a contract to the common thought that a lack of sleep can accelerate these conditions.

The researchers used mouse models to test their hypothesis. They bred mice with both FNSS genes and genes that made them more likely to develop Alzheimer’s disease. Ultimately, even though these mice slept for shorter periods of time, their brains developed noticeably less hallmarks of Alzheimer’s. And even when researchers repeated the experiment with different FNSS genes and different dementia genes, they saw similar results.

This means that the same effect may take place in humans. Efficient sleepers — or those with FNSS genes — may actually be getting good-quality, restorative and even potentially protective sleep, even if they’re getting four to six hours of sleep per night.

The researchers suggest that in individuals with FNSS, the brain is actually able to accomplish its sleep tasks in less time. And, as a result, those genetic differences allow some people to sleep less than eight hours and still get a quality night of sleep.

The Quality of Your Sleep Is Key

While the study’s researchers are hopeful their data can be used to prevent diseases and disorders related to sleep, there’s another takeaway you can apply to your own sleep schedule. Eight hours of sleep doesn’t necessarily suggest that you’re getting enough sleep, or even the best possible sleep for your body. 

If you have those key FNSS genes, you might be perfectly fine — and healthy! — getting just four to six hours of shut-eye at night. However, if you aren’t exactly perky or feeling well-rested after just a few hours of sleep, then you likely aren’t an efficient sleeper. You may need a full eight hours, or perhaps more, to meet your body’s needs. 

Additionally, if you aren’t getting restful sleep at night, that’s where potential health concerns may crop up. Restorative sleep, which is an indicator of your sleep quality, is directly linked to your health. Lower-quality (or a lack of restorative) sleep can be associated with cognitive and physical problems, the APA notes, altering your metabolic health, cognitive function and even risk for neurodegenerative disorders. Poor sleep can also increase inflammation, putting you at an increased risk for inflammatory health conditions, too. 

So, make sure you’re getting restorative sleep that leaves you feeling well-rested come morning.

Need some help fine-tuning your sleep routine or getting the right amount? Keep reading: