The science behind sleep

by Lisa on November 9, 2009

Well, it seems Monday has come once again a lot faster than I predicted. This last weekend was busy with a friend in town and another friend’s birthday. It seems another “Sunday” is always needed after the original Sunday. Luckily, I went to bed at 9pm last night. Going to bed early is one of my favorite Sunday night activities. Sleep is so important for having mental clarity on Monday morning and starting your week off right – so what exactly is it and why do we need so much of it?

Sleep would seem like an anti-evolutionary trait since we spend so much time doing it, and it leaves us vulnerable for predator attacks. Yet, if a person were to go longer than 2 weeks without sleep, he/she would die. We all know that lacking just one day of sleep leaves us groggy and disoriented. Make it three, and delirium is sure to set in.

Although we are not exactly sure why sleep is so important, we do know that during this time our thoughts re-organize, our muscles and organs restore themselves, and we build memories.

There are also 5 different stages of sleep. See below. (*taken from Discovery Health)

  • Sleep Stage 1
    In this brief stage, which may last only a few minutes, the body drifts to sleep. Brain waves are mostly high amplitude, slow waves and occasional alpha waves (like those found when awake).
    Percent of total sleep time for young adults: 5 percent.
  • Sleep Stage 2
    Heartbeat and breathing slow and the sleep is deeper than in Stage 1. Slow-wave sleep continues with peaks of brain waves (known as sleep spindles) occurring.
    Percent of total sleep time for young adults: 44 to 55 percent.
  • Sleep Stages 3 and 4
    These are the stages of deepest sleep, when brain waves are slowest. During these stages breathing and heartbeat slow further and muscles relax. Dreams are more common than in the earlier stages and sleepwalking and talking may occur during Stages 3 and 4.
    Percent of total sleep time for young adults: 15 to 23 percent.
  • REM
    Rapid eye movement (REM) sleep stages lengthen through the night. The first REM cycle may be only 10 minutes while the last could last as long as an hour. During this cycle the heartbeat increases, breathing becomes shallow, eyes move rapidly, muscles are relaxed, and dreams are most vivid. Brain waves resemble those during waking.
    Percent of total sleep time for young adults: 20 to 25 percent.

    Nothing's cuter than a sleeping kitten

    Nothing's cuter than a sleeping kitten

Want to know some other interesting facts?

– Whales and dolphins only sleep 1/2 of their brain at a time. Therefore, if they are sleeping, one eye will be open and the other closed.

– Getting too much sleep (9 hours or more) or too little (6 hours or less) gives a person a 30% higher death rate than those who sleep regularly every night.

It seems getting your beauty rest is just part of the sleep equation, and there’s numerous reasons why we should sleep more. Don’t worry if you didn’t catch up on all your sleep during the weekend, there’s always tonight to get your full 8 hours. Happy Monday!

Information pulled from: http://health.discovery.com/centers/sleepdreams/basics/basics.html, http://www.abc.net.au/science/sleep/facts.htm, Intellectual Devotional by Kinder and Oppenheim

Previous post:

Next post: