When you think about what your body does while you are sleeping, you might understandably believe that most of your systems shut down while you are off in the land of nod.
Even the expression “out like a light” implies that your entire body is in full resting mode and is switched to the “off” position during sleep.
Actually, this is not quite the case. As it turns out, there are a number of body parts that never truly shut down, even when you are happily in dream land.
To learn more about what part of the body never rests, please consider the following:
Your brain Never Stops – Especially During Sleep
Your brain is the life center of your entire body. If it were to completely shut down during sleep—much like you might turn off your personal computer from time to time—your whole body would cease working.
As WebMD notes (1), while your body rests during sleep, your brain remains as active as ever, recharging itself and controlling a number of bodily functions while you snooze.
Actually, to get a bit more technical, your brain does rest during the night, only not the whole thing at once.
After all, your brain is still making sure that you breathe while you are asleep and that other organs are doing their thing, so at least part of it has to remain vigilant during slumber.
Basically, your brain creates two types of sleep: rapid eye movement (REM), which is when you dream, and slow-wave sleep (SWS) which is when you sleep really deeply. Most of your 40 winks will be spent in SWS mode. In fact, your sleep will begin in the parts of your brain that handle the SWS work.
After you are in SWS for awhile, you go into REM mode. Which at this point is when your brain announces “it’s time to dream!” and you go into a sleep paralysis mode. Essentially, this prevents you from acting out your sometimes wacky dreams while you are sleeping.
Curious about how your sleep affects your brain waves and cycles? Read What Part of the Brain Controls Sleep?
Other Parts of the Body that Never Rest
While your brain is the major computer that controls your entire body and never is fully at rest, there are a variety of organs that don’t sleep either.
For example, think about your heart—this amazing muscle works unceasingly, 24/7/365, pumping blood throughout your body and making sure your muscles get enough oxygen.
You might be in the middle of a hilarious dream about eating a big bowl of chips and salsa with the Queen of England, but you heart is still working as hard as ever.
Your lungs also do their thing, regardless of whether you are in SWS or REM sleeping mode. They continue to work and remove carbon dioxide from your blood and make sure it contains enough oxygen.
Another organ that works the night shift as you sleep are your kidneys—their ability to filter your blood and eliminate any toxins from your body does not stop simply because you are snug in your bed.
Again, while your brain is controlling the work of these organs, it is important to realize that a number of your body parts keep on working non-stop, regardless of whether you are asleep or awake.
Aren’t our bodies neat!? Need some more sleep talk? Check out our blog about how sleep helps you stay younger.