Small children shun it like the devil shuns holy water and adults can never get enough of it: sleep. When we sleep we regenerate from our stressful everyday life and the body recharges its batteries. The brain is cleaned up and space is made for something new. But what happens when the body doesn’t get these recovery phases, we danced again until the “clouds are purple again” or jet lag from the last business trip keeps us awake?
Officially, nobody has managed to stay awake longer than Randy Gardner. The 17-year-old managed to go 264 hours without sleeping at a science event in 1965. That’s around 11 days. You shouldn’t do it again. Because to feel the physical effects of sleep deprivation, a solid night is enough. During sleep we process the impressions and images that hit us during the course of the day. Memory content is solidified and the brain is reformatted, so to speak. If we don’t get enough sleep, the processes will become imbalanced.
After just 24 hours without sleep, our neurocognitive abilities begin to decline. Studies show that we are less able to concentrate, our attention span is shortened and we have poorer access to our long-term memory. According to neuroscientist Claudia Aguirre, this is also due to our hormones. She explains in a TED video that we mess up our hormonal cycle when we don’t follow our body clock and force ourselves to stay awake when we’re tired. Among other things, the production of the hormones adenosine and melatonin is out of sync.
What then happens in the head when we are overtired actually resembles that of a state of intoxication. A study showed that after 24 hours of sleep we are mentally impaired in a similar way as with one per thousand alcohol in the blood. As in the drunken state, the reaction speed is slower, we are irritable more quickly and are more willing to take risks. External influences such as bright light or loud noises are more quickly perceived as disturbing because the brain can no longer distinguish between different stimuli – similar to schizophrenia patients. Researchers at the University of Bonn and King’s College have found that sleep deprivation for more than 24 hours can trigger conditions similar to schizophrenia.
Not only is the mind weakened by lack of rest, the immune system is too. Too little sleep opens the door for pathogens. After just 24 hours of being awake, the immune system no longer works as effectively as when it is fit and is less able to fend off pathogens because the responsible cells work in a kind of energy-saving mode. The immune memory also functions less reliably. The body is less able to memorize pathogens, may not recognize them in the event of “re-contact” and react accordingly less well.
It is not possible to say in general terms how much sleep a person needs. According to the Max Planck Institute, there is no “generally valid normal amount of sleep”. Some are more rested after five hours of sleep than others after ten. On average, adults sleep seven to eight hours a night. Those who “can concentrate on an activity during the day, even when sitting for a long time, without getting sleepy,” sleep optimally long. Even small changes in the sleep pattern, ie about an hour less than usual over several days, lead to overtiredness and exhaustion.
Incidentally, record holder Randy Gardner once also suffered from increasing lack of sleep from increasingly serious failures – from memory lapses to mood swings to almost complete inability to act.
Sources: Quarks, Science Spectrum, NIH Study, Journal of Neuroscience, Max Planck Institute of Psychiatry, Spectrum, TED Talk
