Much of a person's life is spent sleeping. In fact, about one-third of our lives are spent asleep. Sleep is vital to survival and most adults require 7 to 9 hours of sleep each night. Children and adolescents need at least 10 hours of sleep daily (Centers for Disease Control and Prevention [CDC], 2017).
When we sleep well, we feel better, we are more energetic, and our nervous system functions more effectively. Sleeping, like eating, is a basic, life-sustaining function and it is regulated by powerful internal drives. Going without sleep, like going without food, produces uncomfortable sensations. Just like eating relieves hunger, sleeping relieves sleepiness and ensures we obtain the sleep we need (Harvard Medical School, 2007).
WAKEFULNESS AND THE BRAIN
Several neurotransmitters contribute to normal sleep and wakefulness. Gamma-aminobutyric acid (GABA), a neurotransmitter in the brain, is considered the most important regulator of sleep. It inhibits the release of serotonin, norepinephrine, and other neurotransmitters. Melatonin, which helps regulate the sleep-wake cycle, is a neurohormone synthesized by the pineal gland in humans and produced in animals as well as plants. Areas in the brainstem and the hypothalamus that promote wakefulness do so by sending arousal signals (called neurotransmitters) to the cerebral cortex, the brain’s largest region. When neurons in the arousal areas are active, the cortex remains activated and the person stays awake (Buscerni et al., 2004).
Changes in normal sleep and waking patterns can result from many factors, including medication side effects, substance abuse, lifestyle issues, and medical problems that directly or indirectly affect sleep-regulating neurotransmitters. When people do not receive adequate sleep or are chronically sleep deprived, every aspect of their lives suffers, contributing to profound physical and psychological disorders.