Basics of Sleep Introduction
Sleep is defined as a state of unconsciousness from which a person can be aroused. In this state, the brain is relatively more responsive to internal stimuli than external stimuli. Sleep should be distinguished from coma. Coma is an unconscious state from which a person cannot be aroused. Sleep is essential for the normal, healthy functioning of the human body. It is a complicated physiological phenomenon that scientists do not fully understand.
What Does Sleep Do For Us?
Sleep appears necessary for our nervous systems to work properly. Too little sleep leaves us drowsy and unable to concentrate the next day. It also leads to impaired memory and physical performance and reduced ability to carry out math calculations. If sleep deprivation continues, hallucinations and mood swings may develop. Some experts believe sleep gives neurons used while we are awake a chance to shut down and repair themselves. Without sleep, neurons may become so depleted in energy or so polluted with byproducts of normal cellular activities that they begin to malfunction. Sleep also may give the brain a chance to exercise important neuronal connections that might otherwise deteriorate from lack of activity.
Most adults need seven to eight hours of sleep every night, and during this time, your body goes through different phases. The four sleep stages of sleep include:
Sleep patterns vary according to age. Most adults go through four to six cycles of all the stages of sleep — each cycle usually lasts between 90 and 110 minutes. Kids go through much shorter sleep cycles. For example, a 1-year-old may experience a sleep cycle that lasts only 45 minutes. By the time a child is about 10 years old; his sleep pattern will closely resemble that of an adult.
The Benefits of Sleep
While occasional sleep loss is bothersome, chronic problems can take a toll on the body. No one understands fully why the body sleeps, but there are certain functions that restore and refresh the body. Your blood pressure decreases; heart rate slows; appetite, stress and insulin hormones quiet; and blood clotting cells take a break. Keep the body awake and you are subject to weight gain, heart disease, mood disorders, decreased immunity, insulin resistance and diabetes.