Whether we realize it or not, sleep is extremely important for the health of our brain and for our overall wellbeing. The time during which we sleep is used by our body to rest and recharge, replenishing our reserves of energy and more. The News in Health publication cited Dr. Maiken Nedergaard, a sleep researcher at the University of Rochester, who stated that “when we sleep, the brain totally changes function. It becomes almost like a kidney, removing waste from the system”.
The lack of sleep has been proven to affect our thinking and concentration abilities, our memory, our mood and our immunity. In time, sleep deprivation may lead to increased blood pressure, increased risk of diabetes, heart disease and dementia, balance issues and weight gain.
How much sleep do we need
According to the Centers for Disease Control and Prevention, most adult people need between seven to nine hours of sleep per night. Things change in the case of children and teenagers, who need between eight to eleven hours of sleep every night. In general, the number of necessary hours of sleep is inversely proportional to the age of the person, but the recommended amount never decreases under eight hours nightly.
To make sure that you are fully benefitting from your resting hours, it’s not only important to get the right amount of sleep, but also to get quality, uninterrupted sleep. In this purpose, it is recommended to stick to a well-defined sleep schedule, to exercise and get fresh air daily, to avoid rich meals and alcohol before going to sleep, as well as to refrain from drinking coffee and smoking. At the same time, you should make sure that your sleeping environment is pleasant, quiet, cool and dimly lit, so it can stimulate somnolence and help you go to sleep faster. If you can’t fall asleep after twenty minutes, it is recommended that you should get out of bed and try doing something relaxing, that can make you feel sleepy.
How sleep works
Our bodies have what is known as the circadian rhythm, which is a 24-hour cycle that controls when we are tired and when we are rested. Research has shown that the circadian rhythm may be affected by two important elements:
- The release of adenosine, a substance produced in the brain, the level of which increases throughout the day as we become more tired.
- Natural light, which can trigger certain processes in the brain that enable it to differentiate between day and night. As a result, in the evening our body releases melatonin, a sleep-inducing hormone, and in the morning, it releases cortisol, a hormone that generates energy.
Once we are asleep, our bodies go through four stages of sleep that will keep repeating until we wake up. Three of these stages are known as non-rapid eye movement (NREM) sleep, while the last stage is known as rapid eye movement (REM) sleep. The first three NREM sleep stages are marked by a constant decrease of the heart rate and breathing, steadily passing from wakefulness to deep sleep. They are followed by the REM stage, in which our brain is highly active and where dreams occur. This stage has been frequently linked with memory consolidation. The four-stage cycle usually last between 90 and 120 minutes, and repeats itself throughout the night until we wake up.