Sleep is such a natural part of life you may have never wondered why you need it! Researchers, scientists and doctors have been studying why humans sleep for decades and while there are many theories, there’s no single answer as to why we do it. We’re beginning to know more about what’s happening in the body during sleep, and it’s well known and accepted as being critical to health and well-being.
There are dozens of theories about why humans sleep and while experts may not agree on one in particular, many agree it’s likely a combination of a few theories. One of the most widely accepted theories is the rejuvenation theory; while you are sleeping your body repairs and rebuilds the immune system. Additionally, muscle growth, tissue repair, protein synthesis and growth hormone release happen mainly during sleep. This is why it is so critical to sleep through the night—especially if you are in pain or under stress.
Another sleep theory that has gained traction, including support from Russell Foster, a professor of circadian neuroscience at Oxford University, is the memory theory. In a presentation Foster gave at a TED Talk, he says that during sleep “brain processing and memory consolidation” is occurring. As proof, he cites a study where individuals were taught a task and those who were sleep deprived were unable to remember or preform said task. It’s also been proven humans have the ability to more easily solve a complicated problem after a full night’s rest—it’s likely because the neuro-connections and synapses in the brain are strengthened during sleep.
What’s Happening While We Catch ZZZ’s
Ever thought about what’s happening to particular parts of your body while you’re asleep? Let’s look at some lesser known facts about the body during sleep:
Heart and Blood – As you rest in the non-REM stages of sleep, your heart rate and blood pressure drop by about 10 percent . But when you enter REM sleep, your heart begins to work a bit more and your heart rate and blood pressure can increase a bit. Researchers and doctors aren’t sure what causes this change, but there are theories related to changes in nervous system activity or dreams.
Body Temperature – Interestingly, while you are in the last stage of sleep, REM, your body temperature will fall to its lowest point of the night. This is when you may grab for the blanket or curl up in the fetal position to help conserve body heat.
Digestive System – We’ve all been told not to eat before bed and there’s a reason why! Your body doesn’t release the enzymes and stomach acids necessary to process food into energy. This leaves your digestive system sluggish and can cause you to feel bloated when you wake in the morning.
Hormone System – When you’re awake, your body is working to burn oxygen and food for energy, a process called the catabolic rate. While you’re asleep, your hormone system changes to an anabolic phase and uses energy for improvement and growth.
Mouth – We’ve all woken up completely parched—but if your mouth is dried out, it’s not just because you haven’t had water all night. Your salivary glands actually decrease activity during the night and produce less saliva.
Skin – Ever heard someone say, “I need my beauty rest”? Turns out they do! During sleep, skin cells increase production and these new cells replace older cells, renewing and rejuvenating your face and body.
On top of these interesting physical changes occurring, there’s evidence that getting the proper amount of sleep on a regular basis can increase your ability to think positively and improve your self-esteem. Sleep tight!