Ever notice your body seems to do certain
things around the same time each day? You wake up around the same time, feel peckish
around the same time, and are tired and ready for sleep around the same time. You might think it’s habit, but it’s actually
thanks to biological processes that keep your body in lock step as the day progresses. That daily clock is called a circadian rhythm,
and most living organisms have one. From fruit flies to daffodils to microscopic
organisms, if it lives under the sun chances are there’s something that keeps it in tune
with the sun’s 24-hour pattern. In humans, there are proteins in nearly every
tissue and organ that help maintain proper timing, but they don’t function independently. Inside your brain is something like a master
clock that all other biological clocks sync up to. This master clock is called the suprachiasmatic
nucleus, and it’s made up of around just 20,000 neurons arranged in two tiny wing-like
structures nestled inside your hypothalamus. The hypothalamus plays a big role in releasing
hormones and controlling appetite, among other things, so the suprachiasmatic nucleus’
place here makes sense if it’s going to be in charge of keeping your body clock synchronized. But it’s not run by gears or bits in a computer,
it’s run by biological processes. In the suprachiasmatic nucleus there are proteins
produced on a negative feedback loop. The proteins (called PERIOD and cryptochrome)
switch off their own production when they build up, and cells resume production once
the proteins degrade. These protein cycles peak about every 24 hours,
though it’s not exact. A 1974 study left 15 people without clocks
or daylight for up to 13 days. The researchers found the humans tended to
live on a day of between 25 and 27 hours. Since these proteins are so important to staying
in sync, genetic mutations that change their structure can throw a person’s internal
clock out of whack. People with familial advanced sleep phase
syndrome produce and unstable PERIOD 2 protein, which speeds up their circadian rhythm. As a result they’re up at 3am and in bed
by 7pm. No partying for them. You may have noticed though that when you
travel or set your clock forward for daylight savings, your body eventually adjusts. That’s because light has a big influence
on your suprachiasmatic nucleus too. The light your eyes take in turns certain
genes in the cells on or off, coding the proteins that keep time. This is why light is the biggest external
factor in keeping a steady rhythm, and why you don’t seem to get tired when you stay
up late looking at a phone screen. But light isn’t the ONLY factor, your body
clock is influenced by things like eating cues and social cues as well. An unstable or abused circadian rhythm can
have medical implications. Lack of sleep and disrupted circadian rhythms
have been linked to obesity, depression, and other chronic illnesses. So if it’s late at night and you’re watching
this, do yourself a favor, put the phone down and get some rest. Or turn on night mode and watch just one more
episode. Like staying up all night watching al science
videos? You should definitely subscribe and check
out my video on how blue light from this very screen is messing with your body clock RIGHT
NOW. Also Fun fact: The term circadian comes from
the latin words circa, meaning around, and diem, meaning day. It’s your rhythm around the day. Neat right? Thanks for watching.

10 thoughts on “How Your Body’s Internal Clock Might Be Messing With Your Sleep”

  1. There was this monk who live 1 hundred of years. He says he sleep too early and wake up early. Nowadays we people are busy working and going home late.

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