There are five basic needs that are essential for human survival: water, shelter, air, food, and sleep. As humans, it is our instinct to sleep each night, this is how we recharge and restore our mind and body, as well as maintaining a strong immune system. Sleep deprivation can lead to multiple problems, depending on the length of time a person has gone without sleep. After just 72 hours of being awake, a person will already start to lose full memory functionality. At this point, the longer you are awake the less you are able to function properly. In addition, prolonged or regular sleep deprivation has even been linked to an increased risk for disease, such as heart disease and diabetes. While all humans innately experience the same 90 minute sleep cycle, some require fewer hours of sleep than others and researchers are trying to figure out why.
According to a study published in Medical News Today, it is our DNA which determines individual sleep requirements. Therefore, some people may genuinely only need five hours while others need ten, but both are “normal”. It doesn’t mean that a person who only needs five hours of sleep is superior to someone who needs more, nor does it mean someone needing more sleep is just lazy. This study was conducted to try and find out why some need more sleep than others, or at least shed some light onto the question.
In the study, Susan Harbison of the National Heart Lung and Blood Institute bred 13 generations of fruit flies and studied them. She compared genes between flies who had longer sleep periods and those with shorter sleep periods. Duration of sleep for the flies studied ranged from 3 to 18 hours. Incredibly, 126 differences within 80 genes were discovered. With so many different genes involved in sleep, scientists say that several factors can influence sleep. Examples include digestion, homeostasis, reproduction, and cell growth. Each of these biological processes are vital to maintaining life. They also found that the duration of sleep, whether long or short, did not have an affect on lifespan.
Although these fruit flies do not have the exact same sleeping patterns as humans, this study is a great start at digging into the possible causes for different sleep behaviors and needs.