Describe the different stages of sleep, and explain why we need to sleep.

The stages of sleep can be divided into Non-REM and REM sleep cycles. Sleep is a critical component of a person's overall health and well-being, as sleep deprivation can lead to physical as well as mental and emotional health problems.

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Sleep is a key component to a person's overall health. It is a basic human need in the same way that eating, hydrating, and breathing are essential human needs. Sleep deficiencies can lead to both physical and mental/emotional health problems. Those problems are in addition to an increased risk of...

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Sleep is a key component to a person's overall health. It is a basic human need in the same way that eating, hydrating, and breathing are essential human needs. Sleep deficiencies can lead to both physical and mental/emotional health problems. Those problems are in addition to an increased risk of injuries and a loss of productivity (at work or home). There is even an increased risk of death from sleep deficiency.

According to the National Institute of Health, lack of proper sleep can actually change brain activity. People with sleep deficiencies have trouble making decisions and solving problems. They also struggle with controlling emotions and behavior. Anecdotally, this is how I know my kids are overly tired.

Sleep happens in stages, and there are two main types of sleep. They are rapid eye movement (REM) sleep and non-REM sleep. Non-REM is what most people refer to as deep sleep. REM sleep is when dreaming typically occurs, and those two sleep cycles oscillate between each other about three to five times per night.

Some sources list five stages of sleep, but other sources, like the National Institute of Health, only include four stages of sleep. The first three stages are non-REM sleep. The first stage lasts only a few minutes and is the changeover from being awake to being asleep. It is a light stage of sleep, but the heart rate and breathing rate do drop.

Stage two is best described as a deeper form of sleep than stage one. You spend most of any given night's sleep in stage two. Heart rate and breathing rate are slowed even more and muscles relax a great deal. Stage three is a deep sleep. It would be difficult to wake a person up that is in stage three. Heart rates are extremely low at this point, and brain waves are also significantly slow. Stage four is REM sleep. It occurs at about the ninety-minute mark of a good night's sleep. The National Institute of Health describes REM sleep brain activity as quite active, and fortunately, your body is momentarily paralyzed, which prevents a person from acting out their dreams.

Your eyes move rapidly from side to side behind closed eyelids. Mixed frequency brain wave activity becomes closer to that seen in wakefulness. Your breathing becomes faster and irregular, and your heart rate and blood pressure increase to near waking levels. Most of your dreaming occurs during REM sleep, although some can also occur in non-REM sleep. Your arm and leg muscles become temporarily paralyzed, which prevents you from acting out your dreams.

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