Why You Need Those Eight Hours of Sleep
Nothing compares to a good night’s sleep. It’s important to start the day feeling energized and refreshed. As you age, the amount of sleep you need differs. Infants need 14-17 hours of sleep, while most adults need 7-8 hours. But what really is sleep? What does it do for us?
Our bodies function around an internal clock. This clock regulates when you are tired, ready for bed, and your sleep cycle. Moreover, our bodies have a circadian rhythm. A circadian rhythm is a behavioral, physical, or mental change that corresponds to a daily cycle. The cycle that corresponds to sleep is called a light-related circadian rhythm. This is controlled by the suprachiasmatic nucleus (SCN) in the brain, which is the part of the brain that regulates circadian rhythms in our bodies; The SCN is responsive to light. Because of this, our bodies are most alert when it is light out. The SCN is responsible for producing more melatonin when it senses less light, meaning more is produced at night.
There are multiple stages to sleep that are key to ensuring that the body recuperates after a day of being awake. The first stage is non-rapid eye movement or Non-REM sleep, which serves as a bridge between wakefulness and sleep. Non-REM consists of light sleep, lasting only several minutes. Your body begins to go into sleep mode by slowing your breathing, heart rate, and eye movements. Additionally, your muscles start to relax, twitching slightly. The second, and longest, stage is still classified as non-REM sleep. However, in this stage, you are transitioning from light sleep to a deeper sleep. Your breathing and heart rate continue to slow, while your muscles relax further. Moreover, eye movements stop completely and your body temperature drops slightly. Your brain waves remain slow, but in this stage there are still slight bursts of electrical activity, meaning that the brain is not fully in sleep mode.
Stage 3 also aligns with the non-REM category of sleep In this period, you enter into a deep sleep. Deep sleep is where your breathing, brain wave activity, and heart rate are at their lowest, and your muscles are completely relaxed. This deep sleep is essential for feeling alert and refreshed the next morning, as it is when our bodies recharge. Stage 3 only occurs in longer periods during the first half of the night and decreases throughout the rest of the night. Rapid eye movement sleep, or REM, occurs only during the first 90 minutes of sleep. This stage is called rapid eye movement because your eyes are moving back and forth under your eyelids. Furthermore, your breathing, heart rate and blood pressure increase almost to waking levels. Most dreaming happens in REM sleep, and interestingly, your arms and legs become paralyzed so you do not physically react to your dreams.
So what do all these stages of sleep do for us? One of the most important things that the stage of REM does for us is store the information you obtained during the day and put it in your long-term memory. During deep sleep in Stage 3, our body works to repair tissue, replenish energy for the next day, and boost your immune system. Without the correct amount of sleep, you can risk the dangers of sleep deprivation. Sleep deprivation can lead to serious problems, such as delayed reactions, slower cognitive function, a weakened immune system and vulnerability to attention lapses. Moreover, sleep deprivation can subject you to a higher risk of obtaining serious conditions such as diabetes, obesity, or even a heart attack. Ultimately, sleep is a necessity to be able to function correctly. No matter what age, sleep deprivation can cause serious health problems, which is why getting the correct amount of sleep each night is essential to your wellbeing.
References:
https://www.sleepfoundation.org/articles/how-much-sleep-do-we-really-need
https://www.webmd.com/sleep-disorders/sleep-requirements
https://www.nigms.nih.gov/education/fact-sheets/Pages/circadian-rhythms.aspx
https://www.ninds.nih.gov/Disorders/patient-caregiver-education/understanding-sleep
