An I-STEM project.
When you sleep, the benefits and effects of sleep occur in 1.5 hour cycles. These are referred to as sleep cycles and the longer you sleep, the more cycles are carried out, leading to better rest. Sleep cycles matter as you go through all 4 phases multiple times in a night in a full night's rest. Waking up in the middle of a cycle can make you feel groggy or tired. This is why sleeping 6, 7.5 or 9 hours feels better than 5 or 8: you're ending a full cycle!
Here's a breakdown of the stages:
This is an extremely early stage of sleep, usually what happens in the first few hours.
- In this stage you are just falling asleep.
- Muscle activity slows down, calming your body.
- Your brain waves will now start to slow down, transitioning your body into deeper rest.
You are likely to spend most of your time sleeping in this stage.
- Your heart rate and body temperature will now begin to decrease.
- Your brain continues to slow down.
- This stage is affecting the nervous and circulatory systems, as the brain reduces nervous system activity while your heart slows in order to conserve energy.
As the name suggests, this is the deepest point of sleep.
- This stage of sleep is extremely difficult to wake up from.
- Your muscular and immune systems are now affected, as muscle tissues repair during this stage and the immune system is strengthened, helping fight infections.
- This stage is the most important for physical recovery.
This is the last stage of a sleep cycle.
- The brain's activity increases.
- This is when most dreaming occurs.
- This stage is important for your memory, learning and mood.
- The nervous and endocrine systems are affected here, as the brain sorts memories and releases key hormones related to stress and mood, such as cortisol.
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