It’s strange indeed that, in this day of modern science, with everything from space travel to organ transplants, science has not produced an answer to the question of why we require sleep! Although there are several theories, there’s still no definitive, proven answer. All animals are compelled to sleep. If we don’t sleep, we ultimately die. Our brains, one theory has it, simply requires it, but the rest of the body feels like it requires it too when we don’t sleep. When we have a bad night’s sleep, our strength is diminished and our steadiness is less than best. Some people do quite well on six or seven hours of sleep, while others need nine or ten to avoid that foggy feeling the next day. We rarely think we have had too much sleep, and we can feel when we haven’t had enough, but there are no hard and fast rules that tell us how much sleep we must have. Each of us discover our sleeping needs as we age.
The sleeping patterns of infants are also variable, but in general they seem to need more sleep than older children. Gradually, their sleeping patterns become more regular, as the baby’s brain synchronizes with the rising of the sun. We fall asleep when our brain senses a buildup of certain chemicals, especially adenosine, produced by our bodies throughout the day. When these chemicals reach a certain level, a part of our brain signals other parts of our brain and body to stop producing other chemicals, such as histamines, which keep us awake. After these ‘stay awake’ chemicals gradually decline, we fall into a light sleep, going in and out of sleep for a short time. Finally, we plunge into deep sleep and our brain activity decreases. The state of deep sleep, however, is interrupted several times throughout sleep, by increased brain activity and rapid eye movement (REM). During the REM periods, we may dream. REM sleep is also associated with the assimilation of our wakeful experiences into our world view. Infants and children have REM sleep more often than deep sleep. REM sleep increases our ability to discern patterns when we’re awake. An infant has much to learn, and so, REM sleep is highest in infancy and early childhood. REM sleep decreases by as much as 50 percent as children enter puberty.
The sleeping patterns of a child are more irregular than that of a teenager. Often, a child’s sleep is interrupted by nightmares, but they rarely suffer from insomnia. In puberty, a teenager is better oriented to the world, more secure, so they suffer less from night terrors than younger children. With puberty comes psychological and social concerns that occupy a teens thoughts and imagination. They have later bed times and so, wake later. Much occupies their minds.
Normal sleeping patterns comes with adulthood. Adult sleep lasts about eight hours and few dreams interrupt the sleep. Disruption of sleep may be caused by the introduction of a new baby in the family, or by work schedule demands. They will sleep regularly, however, unless they are beset by sleeping disorders such as psycho-physical insomnia or sleep apnea.
Elders tend to become sleepy earlier than when they were younger adults. Although more sleep would be best for them, they tend to sleep less and to wake earlier than when they were young. This may reflect their reduced strength and the inevitably shorter life expectancy.
Beyond these general, age-related sleeping patterns, not more can be said. Sleeping patterns vary widely and, unless you’re not getting enough sleep, you have no reason to be concerned if yours differs from your peers. One thing is certain: we all need sleep, from the infant to the elderly. In that much we are the same.