The average human being will spend approximately 24 years of their life sleeping. Experiments involving humans intentionally depriving themselves of sleep have documented decreased immune function. Impaired cognitive ability, and even hallucinations. While the subjects in these experiments have often showed no permanent or long-term damage. Physically or psychologically, it remains that sleep is critically important for our health. Many of us are aware of this and scientists encourage people to get somewhere between seven and nine hours of sleep per night. Sleep is as routine as breathing air in most of our lives, but it still is not quite clear how much sleep is an adequate amount.
The longest documented sleep deprivation experiment involved Randy Gardner, a high school student in California. Under supervision, Gardner stayed awake for 11 days and 24 minutes. While Gardner showed no long-term negative effects from the experiment, negative short-term effects were observed almost immediately. After only 24 hours awake, Gardner’s eyes began showing an impaired ability to focus and he began struggling with identifying objects by touch. After day three to the end of the experiment, he exhibited paranoia, moodiness, and even began hallucinating. Going days without sleep is unlikely to kill you, but there are clear negative effects to sleep deprivation.
Even the busiest among us will find time out of each day to get some well-needed sleep. Most of us will not need to be awake for several days at a time, but many of us end up getting far less than the recommended 8 hours of sleep each night. Ironically, consistently not getting enough sleep, despite getting sleep daily, may actually be worse for you long-term than not sleeping for 11 days, but then getting regular adequate sleep afterwards. While Gardner did not receive any long-term damage from his sleep experiment, it is well-documented that not getting enough sleep on a daily basis can have long-term negative effects.
Chronic sleep loss is generally defined as not getting at least seven hours of sleep per night. Getting less than seven hours of sleep has been linked to impaired cognitive ability and an increased risk of obesity, heard disease, and diabetes. It also carries a 12 percent higher risk of death. Interestingly, sleeping more than eight hours per night is also linked to the aforementioned diseases, but increases risk of death by 30 percent. As bad as it is to not get enough sleep, getting too much sleep may be even worse for your health and mortality.
Although the evidence suggests that sleep is critically important, and the adequate amount is believed to be around seven to eight hours, there are many factors that increase or decrease disease risk and human wellbeing, with sleep only being one factor in that equation. The general guideline of seven to eight hours is often based on self-reported data and some researchers believe that these numbers may be overinflated. This is due to people associating time spent in bed as the total amount of sleep, as opposed to the amount of actual time they spend sleeping.
Researchers have observed that members of modern hunter-gatherer societies typically slept no more than six and half hours per night. Incidences of common diseases that plague industrialized nations like diabetes, obesity, heart disease, and hypertension are relatively rare in hunter- gatherer groups. It was believed that our ancestors typically went to sleep when it got dark and woke up when the sun rose, but observations of these modern hunter-gatherer societies show that they often stay awake several hours after darkness.
UCLA scientist Jerome Siegel tracked the sleep habits of the Hadza people of Northern Tanzania, the San of Namibia, and the Tsimané who reside in the Andean foothills of Bolivia. Dr. Siegel found that these hunter-gatherer groups kept similar sleep patterns, despite the considerable distances between them. It is believed that these hunter-gatherer groups live their lives similarly to the way they lived thousands of years ago. His observed that these groups rarely took naps during the day and slept through the night with no segmented intervals.
This casts doubt on the idea that our ancient ancestors slept in the segmented pattern that was found in documents from the Renaissance period in Europe. These groups were also not basing their sleep as much on sunrise and sunset, but on the temperature of the environment. Dr. Siegel observed that all three groups went to sleep during the coldest part of the night and woke up when the temperature began rising.
Sleep is universally know to be very important to our health, but many of us still do not make the greatest effort to get adequate amounts of sleep. While it is generally recommended that you get at least seven hours of sleep, this number is usually based on sleep studies where people self-report data. It is possible that these numbers are inflated and that we may actually need less sleep than the recommended 7-8 hours, Research has shown that hunter-gatherer societies typically get six and half hours of sleep per night and common diseases like diabetes and heart diseases are largely absent in these populations. While it is not entirely clear exactly how much sleep we should be getting each night, what remains clear is that sleep is still not well understood and a lot of research on the subject is yet to be done.
