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The Science of Sleep

Updated: Mar 27, 2020

By: Megan Tseng

It is a universally acknowledged truth that we all need a solid 8 hours of sleep.

So how much sleep did you get last night? 7 hours? Not enough. 7 and a half hours? Still not there yet. 7 hours, 59 minutes and 59 seconds? Not quite! 8 hours? Perfect! You’ve finally gotten enough sleep.

I’m sure this familiar dialogue is frustrating to a lot of us. Why do we need 8 hours of sleep if we only feel like we need 7? What if our bodies don’t require more than 7 hours? Scientifically speaking, what we’re referring to here are sleep homeostasis and the circadian clock.

The Sleep “Homeostat” and the Biological Clock

Sleep patterns are regulated by sleep homeostasis and the circadian clock.

Sleep homeostasis is a mechanism in your body that tells you that you need to sleep. It’s as simple as that. After you wake up in the morning, your body gradually accumulates exhaustion throughout the day, and when you go back to sleep at night, all this exhaustion fades away. So how do we manage to stay awake until bedtime? The credit would be due to the circadian rhythms, or in other words, the body’s internal biological clock. The circadian clock times our periods of being asleep and awake. It’s something that most of us don’t notice in daily life; after all, we’ve fallen into the routine of sleeping at night and waking up in the morning. However, if you’ve ever gone on an overseas trip to the other side of the globe, you probably remember the dreaded feeling of #jetlag: wanting to sleep at one in the afternoon, and being wide awake at two in the morning. That would be the result of your circadian clock being flipped upside down and trying to adjust to the 12-hour time difference.

Individual Genetics

Studies have proven that the “universally acknowledged truth” of needing an absolute 8 hours of sleep no longer stands true. Individual genetics, the varying DNA makeup of every person, may cause circadian rhythms to vary considerably between different people. Typically, the rate at which different processes happen within the circadian clock fits into a 24-hour cycle; so after a day, the clock is reset. As we know, genes regulate and facilitate all mechanisms in the body, including the circadian clock. Studies have shown that small changes in genes influencing the circadian clock can affect its rates of protein production, assembly, and degradation, thus affecting circadian rhythms. In other words, “gene differences” from one person to the next make everyone’s sleep patterns unique.

Examples of people with different sleep patterns are “morning larks” and “night owls.”

What does this mean for us? Well, you may be familiar with the phrases “morning lark” and “night owl.” If you’re a #morninglark, you tend to start your day pretty early. If you’re a #nightowl, you prefer staying up later at night. Again, studies show that the differences in these sleep patterns are due to individual genetics. “Morning larks” have circadian clocks that run faster than the typical 24 hours, telling them to wake up a whole lot earlier than everyone else. “Night owls” have circadian clocks that run a bit slower, letting them get a bit of extra nighttime productiveness in before telling them to go to sleep. Thanks to the genetic diversity in humans, your preferred sleep pattern is not entirely hereditary. Even if your parents are both “night owls,” you can still be a “morning lark” if you’ve got the right DNA.

What Now?

It’s exciting to see that these studies are actually changing the way the scientific community views sleep. The National Sleep Foundation now recommends new sleep times, defined in categories of “recommended,” “may be appropriate for some individuals,” and “not recommended.”

The new ranges are much broader and more inclusive of farther ends of the sleep pattern spectrum. The “appropriate” sleep time for teenagers, which, as we all know, was commonly thought to be a strict 8 hours, has now been amended to 7 to 11 hours.

Although this doesn’t mean it’s okay to pull an all-nighter playing video games while chugging caffeinated drinks, it does give us all some room to change our sleep schedules according to what we feel is best. Hopefully, research will further our understanding of the circadian clock, so that one day we can perhaps determine the exact amount of sleep each of us needs for the optimal snooze.

But in the meantime, #goodnight and sleep tight!

Works Cited

Being a morning or a night person is influenced by how fast or slow our internal clocks tick. Healthy Sleep, Harvard Medical School, 18 Dec. 2007,

Division of Sleep Medicine at Harvard Medical School. "Individual Variation and the Genetics of Sleep." Healthy Sleep, Harvard Medical School, 18 Dec. 2007,

Gustar, Andrew. Lie In. 16 Dec. 2015. Vice, 21 Jan. 2016,

"National Sleep Foundation Recommends New Sleep Times." National Sleep Foundation, 2 Feb. 2015,

"Sleep Drive & Your Body Clock." National Sleep Foundation,

Turk, Victoria. "Why Do Different People Need Different Amounts of Sleep?" Vice, 21 Jan. 2016,


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