You’ll spend nearly one-third of your life asleep. Sleep regulates appetite control, muscle recovery, mental health, and emotional stability while preventing diseases and disorders like diabetes, high blood pressure, and heart disease. However, many people aren’t aware of the complex nature of this necessary biological function.
The Five Sleep Stages
Your body goes through five or six 90 to 120-minute sleep cycles per night. In each of those cycles, the body enters each of the five sleep stages. Though it doesn’t spend an equal amount of time in each stage, every stage contributes to your overall health.
The mind and body drift in and out of sleep during this first sleep stage. Muscle activity slows as does eye movement. If you’ve ever jerked yourself awake with muscle contractions, you were still in stage 1 sleep. Many people experience a sense of falling because of the speed at which the muscles relax.
During stage 2, brain waves begin to slow with only an occasional burst of activity. Eye movement stops, and your body temperature and heart rate drop in preparation for the deeper sleep stages.
During this first of the deep sleep stages, brain waves transition for the subsequent deeper sleep stages. Though you still experience some faster brain activity, long slow brain waves called delta waves start to take over. Sleepwalking, night terrors, and bedwetting often take place during this stage.
The brain almost exclusively produces delta waves during stage 4 sleep. It’s very difficult for adults or children to wake up from stage 4. It’s these deep stages, three and four, that reduce the sleep drive, making them essential to your next-day energy levels.
Rapid Eye Movement (REM) Sleep
REM sleep may last anywhere from 10 minutes to an hour, depending on the timing of the sleep cycle. During REM sleep, limbs and muscles are temporarily paralyzed, the eyes jerk back and forth, and brain waves become similar to those experienced during the day. Your heart rate and blood pressure increase while your breathing becomes shallow, irregular, and rapid. Vivid dreams also take place during this sleep stage though you may not remember them.
You don’t necessarily progress through each of the sleep stages in order. You may shift between stage 1 and stage 3 or REM sleep and stage 2. Your body needs all of the sleep stages, which makes it important to not only spend adequate time in bed but promote healthy sleep habits so the quality of your sleep remains high.
Poor Sleep Habits and Sleep Disorders
Your behavior and habits during the day can come back to affect your ability to sleep at night. Caffeine consumed within four hours of bedtime, for example, blocks sleep hormones and could keep you awake for hours. Screen time can have a similar effect because the bright light given off by some electronic devices suppresses sleep hormones. You can help yourself by focusing on healthy sleep habits like going to bed at the same time every day and following a calming bedtime routine.
However, some people may still have trouble falling and staying asleep. In that case, there may be a sleep disorder or nighttime behavior interfering with your sleep. Sleep apnea, restless leg syndrome, and even teeth grinding can disrupt your sleep cycles. Consult your physician if you suspect a sleep disorder. Sometimes the solution can be as simple as a therapeutic pillow or specialized mouthguard.
Sleep is important enough that it can’t be ignored. With a better understanding of what it does and why you need it, you’re ready for better sleep.