What Happens During Sleep?

Sleep is essential for keeping our bodies and minds healthy. Without enough sleep, we can feel sluggish and moody. Getting plenty of sleep, on the other hand, helps us maintain a healthy weight and can help prevent heart disease, diabetes, and even stress.

During the sleep cycle, our brains begin to organize and store the information we’ve gathered throughout the day. It also converts short-term memories into long-term ones. We also release growth hormone and other chemicals that repair our organs and tissues. In addition, while we sleep, our brains work to recall and process the events that have happened during the day—and to build new connections between neurons.

Scientists have discovered that the body’s immune system is particularly active during the night, when our blood pressure and levels of certain hormones are at their lowest. It’s not known exactly what triggers this response, but scientists suspect it is linked to the release of the stress hormone cortisol in response to a threat. This reaction is a natural part of the body’s fight-or-flight response, and it’s thought to protect us from diseases such as infection and cancer.

While the precise purpose of sleep is not understood, it is considered a dynamic state that influences all aspects of physiology and reduces sensitivity to external stimuli. It is a common and necessary part of the sleep-wakefulness cycle that occurs in all higher vertebrates, including humans.

The timing of sleep varies with age, from newborns to adults, because there are significant developmental changes in the sleep patterns of our central nervous systems. During the early stages of human development, sleep is relatively short and frequent, and the brain shows low-voltage mixed-frequency EEG tracings with a substantial representation of theta wave activity (4-7 Hz). During this stage, intermittent short sequences of waves of 11-15 Hz called spindles occur, indicating that the brain is entering the first of the three phases of NREM sleep.

During NREM sleep, our eyelids and ears remain open, but the muscles around the mouth and eyes become tense to prepare for awakening. During the deeper NREM stages, we often dream. We can also arouse ourselves from NREM sleep by making loud or sudden noises.

Many people snore, but this is usually not a sign of a sleep disorder. However, if it interferes with your ability to get a good night’s rest, you may need to seek medical attention.

If you are having trouble sleeping, try to go to bed at a regular time each night and avoid caffeine, alcohol and heavy meals within an hour of going to bed. You should also avoid using devices like phones and tablets before you go to bed, because the blue light from them can interfere with your sleep. Create a calming bedroom environment by turning off bright lights, putting on white noise or listening to soothing music. A warm bath or a light massage can help to relax you before going to bed.