Sleep is a critical component of overall health and wellbeing, and in today’s fast-paced society, it can be hard to make sure you are getting enough. Adequate sleep is associated with numerous benefits including increased productivity and concentration, lower risk of heart disease, stronger immune health, and so much more.
The Stages of Sleep
Lightest stage of sleep and usually lasts about 7 minutes. You can be woken up easily during this stage and the body starts relaxing muscles and slowing down breathing.
Still a light stage of sleep, but the sleeper is less likely to be wakened. Heart rate and breathing continue to slow down and this stage usually lasts around 25 minutes.
Slow Wave Sleep (SWS) starts to occur. This is considered deep sleep which is restorative, and it is difficult for the sleeper to be wakened. This stage helps you feel refreshed in the morning. In this phase, the body starts to repair tissue and muscle, encourages growth and development, and improves immune function.
REM sleep (Rapid Eye Movement) usually happens about 90 minutes after falling asleep. The name comes from the fact that your eyes dart back and forth behind your eyelids quickly. The brain is very active during this stage which usually creates dreaming. This stage is critical for learning, memory, daytime concentration, and mood.
- The REM stage accounts for about 25% of sleep time and you want to achieve five or six cycles of sleep which is equivalent to seven to nine hours of sleep
- Sleep disorders like insomnia or obstructive sleep apnea may affect REM since you wake throughout the night
“Circadian rhythms are 24-hour cycles that are part of the body’s internal clock, running in the background to carry out essential functions and processes. One of the most important and well-known circadian rhythms is the sleep-wake cycle.” (National Sleep Foundation, 2020).
The body responds to light exposure to either keep us awake or promote sleep. When the sun begins to set in the evening and the amount of light in our environments begins to decrease, the body produces a hormone called melatonin which helps individuals fall asleep and stay asleep. The 24 hour sleep-wake cycle affects almost every system in the body (NIH, 2014).
The National Sleep Foundation recommends that adults aged 18-64 get seven to nine hours of sleep per night. For adults 65+, the recommendation is 7-8 hours per night.
Roughly one third of US adults report not getting the recommended amount of sleep per night. Not getting enough sleep can increase an individual’s risk of chronic disease such as diabetes, heart disease, and depression (CDC, 2020). Signs you are not getting enough sleep include difficulty concentrating, puffy eyes, dark eye circles, feeling hungrier, irritability or moodiness, depression, and increased bouts of illness (NIH, 2021).
Sleep quality is measured by four things:
- Sleep latency: how long it takes you to fall asleep. An indication of good sleep is falling asleep within 30 minutes
- Sleep waking: how often you wake up throughout the night. An indication of good sleep is waking up once or not at all
- Wakefulness: how many minutes you spend awake during the night. An indication of good sleep is 20 minutes or less of wakefulness
- Sleep efficiency: The amount of time you spend sleeping while in bed. This should be 85% or more
Sleep Hygiene 101
- Light slows the production of melatonin which is a naturally occurring hormone that promotes sleep. Keep your bedroom as dark as possible!
- Lower the temperature in your room — ideal temperature is 60-67 degrees.
- Make sure that your bedroom is quiet — reduce noises like Television. If you have loud neighbors or live on a busy street, consider using white noise machine.
Sleep disorders require medical attention and individuals should seek out a specialist for more appropriate intervention.
The National Sleep Foundation encourages individuals to talk with their doctors if they are experiencing one or more of the following signs: