On average, humans spend a third of our lives sleeping. While a favorite activity to some, sleeping is one of the essential parts of human lives that sustain it, restore our bodies, and even prolong our lives. Sleeping disturbances have devastating effects on the human body, and even a single night without sleep can cause symptoms and “borrow happiness” from tomorrow. One would think that the organ most affected by a lack of sleep is the human brain. While there is some truth in this statement, and sleep allows for the brains functions “to reset” and restore during the night – there is virtually no organ system in the human body that remain intact by missing on sleep. From clearing the hippocampus and restoring our ability to concentrate and create short term memories, sleep supports the immune system, the metabolism, and even skin health. Have you seen what the area under your eyes looks like after missing on sleep? Research shows that individuals deprived from sleep after a period of time show signs of non-specific immune suppression thus lessening the ability for our bodies to fight infection. Affecting certain parts of the immune system even leads to increasing the risk of certain cancers, and sleep deprivation has been classified as a type 2B carcinogen according to the WHO.
The amount of sleep humans need varies according to age. Studies show that our circadian rhythm changes throughout our lifetime, with newborn babies needing around 22 hours of sleep during the day. Our newborns have that in common with certain species of the animal kingdom. Teenagers typically require from 8 to 10 hours a day, and adults require anywhere from 7 to 9 hours of consecutive sleep at night for optimal functioning, while older adults have needs between 7-8 hours a night. The difference in the natural time to go to sleep and waking up changes as well. For older adults, going to bed moves toward the earlier hours of the night, with earlier wake up time. Teenagers, however, have a circadian rhythm that is shifted for two hours of that of the adults. Adults typically feel the need to go to sleep around 10pm, while teenagers feel that same urge around midnight. No wonder teenagers like to stay late. In consequence, teens natural wake up time is shifted by two hours, so instead of waking up at 6am, teenagers tend to want to “sleep in” until at least 8am. Individual differences in this cycle have been noted. The sleep cycle, including going to bed and wake up times, are important in allowing NREM and REM phases. These two phases are explained in another article of this website.
Goran Stevanovski MD, MA
