Wellness Wednesday: The Science of Sleep
Did you know that sleep accounts for ¼ to 1/3 of the human lifespan?
So what does our body do during sleep? Sleep is a period when the brain is engaged
in a number of activities necessary to life, which is closely linked to our quality
of life.
Throughout your time asleep, your brain will cycle
repeatedly through two difference types of sleep: Your REM (rapid-eye movement)
sleep and your non-REM sleep.
Non-REM sleep is the first cycle of sleep and is composed of
4 stages.
1. Between being awake and falling asleep
2. Light sleep: our hearts and breathing regulate & body
temperature drops. You spend more of your time during your repeated cycles in this
stage
3. Deep sleep: this period of deep sleep is what you need to
feel refreshed in the morning
4. Deep sleep: REM
Non-REM sleep is important for our learning and memory. In REM
sleep our eyes move rapidly behind our closed lids and our brain waves are
actually close to what they look like when we are awake. The cycle will repeat
itself over the night, but over each cycle you spend less time in the deeper
stages of 3 and 4 and more time in REM sleep. Most people will go through the
cycle 4-5 times.
So what controls our sleep?
There are two main processes called the circadian rhythm and
sleep drive (also known as sleep-wake homeostasis) that help regulate our
sleep.
Most of us have heard of our circadian rhythm which is
controlled by a biological clock located in our brain. A key function is to
respond to light cues by increasing the production of the hormone melatonin at
night, then switching it off when it senses light.
Sleep drive talks about our desire to sleep. Throughout the
day your desire for sleep build and when it reaches a certain point, your body
tells you that it needs to sleep. When you’re exhausted your body is able to
even engage in micro sleep episodes for 1-2 seconds while your eyes are open. Sleep
drive is why napping longer than 30 minutes later in the day can throw off your
night’s sleep.
How much sleep do we need?
- Babies need about 16-18 hours a day pf sleep, which allows them to boost their growth and development, especially in the brain
- School age children and teens need about 9.5 hours of sleep
- And adults need anywhere between 7-9 hours of sleep
How does shift work impact our sleep and health?
Many people who work shift work struggle with the ability to
sleep solidly because their internal clock is usually set to be awake during
the day. Staying awake during the night becomes a struggle because their
circadian alerting system is at its lowest point and its desire to sleep is
quite strong. While we try very hard to sleep during the day, the day to day
responsibilities and social obligations often make it difficult to completely transition.
Then when we are required to switch again our internal clock must then also
shift again. Without a constant sleep/wake schedule, the body’s internal biological
rhythms always remain out of sync. It’s similar to how you feel with jet lag,
but in a more constant state.
Tomorrow we will be going over some strategies and resources
to help with your sleep!
Sources:
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