Humans spend one-quarter to a third of their life sleeping. However, there are several factors that can disrupt the quality of our sleep. Research has revealed that sleep affects the way our brains work, including how we process emotions. To understand the importance of sleep, we should look at the evolutionary history of humans. Sleep was first used by animals and later adapted for humans. Now, we know that sleep can enhance the quality of our lives.
Biologically, sleep is a complex and recurrent state that is accompanied by complex changes in human physiology, including coordinated brain activity, reduced critical reactivity, and relaxation of the body. While its purpose is still unclear, there is no doubt that sleep influences all aspects of our physiology. This is in contrast to wakefulness, a state of enhanced sensitivity that is also a distinct physiological state. The most striking aspect of the sleep-wakefulness alternation is its periodicity.
A lack of sleep decreases the immune system, increases the risk of respiratory infections, and reduces the quality of life. Lack of sleep has also been shown to affect the production of hormones that control hunger and fullness. It also affects the production and release of insulin, affecting the regulation of our body weight and risk of type 2 diabetes. Additionally, sleep regulates our metabolism and helps us repair our heart vessels. Even one night of lack of sleep can create a prediabetic state.
Researchers have also noted that different components of sleep physiology may affect certain aspects of the adult brain. For example, the activity of certain regions of the brain that control the emotions, such as the temporal lobe, becomes more active during the REM stage of sleep. These changes may have a beneficial impact on our mental health and performance. If we’re feeling stressed, or anxious, sleep helps us process these emotions and help us cope with them.
Studies of the brain’s electrical activity during sleep have shown that humans experience intermittent and continuous REM states. In humans, the tonic phases of this state include low-voltage EEG activity and suppressed muscle tone. Intermittent events occur during REM sleep, including rapid eye movements and spikelike electrical activity in vision-related areas of the brain. These intervals can be classified as theta waves. In REM, our brain is active for about four hours during the night, with each REM phase lasting between one and two hours.
The fourth and final stage of sleep is the deepest. During the NREM stages, our heart and breathing rates slow down and our muscles relax. We will also have reduced eye movements and body temperature. Stage two of the sleep cycle is the most restful, and is crucial to feeling refreshed the next day. It will last for about 50 minutes at the beginning and gradually decreases throughout the night. The three phases of sleep are interdependent on each other and are not mutually exclusive.
The most common stage is REM. In mammals, this is characterized by low-voltage mixed-frequency EEG activity and intermittent REMs. The REM sleep stage also displays diffuse patterns of neural activation and deactivation, which may represent the various neural processes involved in dream production. This sleep phase is called REM-sleep. There are various types of REM-related dreams. To understand these dreams, you need to know how the brain works.