The real deal on how much sleep we need: Why what we think we need is different from what we really need

It’s no secret that we all have our special preferences – just stand in line at the coffee shop and you’ll hear countless drink orders, from soy milk to vanilla flavoring or extra ice and cinnamon sprinkles. Knowing what we like and don’t like is part of what makes us human.

That doesn’t always make us right, though. Sometimes we don’t know ourselves as well as we’d like to think! Take sleep, for instance. Many of us think we have a handle on how much sleep we need. But scientific studies show otherwise. Over the long term, sleep deprivation and chronic lack of sleep actually make it harder for us to accurately gauge whether we are getting the appropriate amount of sleep.


The science behind sleep quantity

 When people experience chronic sleep deprivation, a slew of negative repercussions swing into effect. Studies have shown increased chances of obesity, diabetes, depression, and some cancers. Not to mention all the safety consequences of being sleepy behind the wheel.

University of Pennsylvania researchers have discovered that the notion of reducing sleep without triggering negative consequences is just a myth. They tested sleepers experiencing only 4 or 6 hours of sleep each night over the course of 14 consecutive nights and compared them to sleepers getting the recommended 8 hours a night.

They showed that this partial sleep deprivation caused each trial participant to experience lower cognitive function, and be less behaviorally alert. These impairments continued to increase nearly linearly during the whole two weeks of partial sleep deprivation. The degree of impairment after two weeks was almost equivalent to experiencing “two nights of total sleep deprivation.” Amazingly, while the participant’s actual performance showed dramatic deterioration, they reported feeling only “slightly sleepy!”


Why do we get it so wrong?

Well, this research suggests that the more sleep deprived we are, the less we’re actually able to determine how impaired we really are. When we are sleep deprived we simply lack insight.

Think about the dance floor at a wedding. After the champagne toast, the dance floor is filled with people who’ve somehow decided that their dance moves represent peak smoothness. What happened? Well, the alcohol weakened their ability to accurately assess their true performance. It’s fun in the short term, sure! But with sleep, when we’re not getting enough, we become that bleary-eyed CEO clutching a triple espresso shot insisting that we can function just fine on four hours of sleep. And, as you can see, studies show that over the years, we pay the cost with our health.

It’s the unfortunate truth: When you’re sleep deprived, you’re less able to self-assess. Know thyself? Not when you’re sleepy.


 How much sleep do you need?

Research has shown that the average value for human sleep need is about 8.2 hours. Now, back in the 1960s, it was common for people to be getting 8 hours of sleep each night. By 2002, though, many people had succumbed to lower levels of sleep, achieving only 7 hours of sleep each night. By 2016, lack of sleep has become the unfortunate norm, with 40% of people sleeping 7 or fewer hours and 30% of people sleeping 6 or fewer hours each night. The CDC calls sleep deprivation a “public health epidemic.”

And, it turns out that the cost of sleep deprivation is cumulative. Missing out on a few hours of sleep here and there adds up, until your body is running a significant deficit. After lack of sleep, your physical health and mental alertness take a hit – resulting in weaker performance all around. When you’re sleep deprived, it shows.


Benefits of adequate sleep

 Let’s step away from the dance floor and set down the max-caff espresso for one moment. What happens when you begin to get enough sleep? The good news is that your body is an expert at repairing itself.

When you begin to pay off that sleep debt, ending the cycle of sleep deprivation, your body begins to reset in healthy ways. As you accumulate nights of adequate sleep, your sensitive internal rhythms and processes return to healthier cycles, working at optimum levels. Scientific research shows that your immune system gets stronger, and your body’s natural hunger and appetite hormone fluctuations re-sync.

You’ll feel more energetic and mentally calm, able to make better decisions – opting for an evening walk rather than happy hour, for example ­– so that one good decision leads to another good decision.

In time, as your body returns to its preferred level of rested, energized, and healthy cycles, you’ll notice that you’re better able to gauge your genuine need for sleep. It feels good to say good-bye to sleep deprivation.

Moral of the story? While we might feel that we can adjust to the lack of sleep we get, the reality is that it has an accumulating effect on our well-being – a negative effect. There’s no cutting corners when it comes to sleep!