Experts from various fields of scientific knowledge (neurobiology, mathematics, statistics) analyzed more than 60 human and animal studies. It turned out that in all species on Earth there is a reduction in REM sleep as they grow older. During the first 2.5 years of life in humans (and equivalent periods of time in other animals), its maximum decrease occurs.
For example, newborns spend about half the time in REM sleep while they sleep. By the age of 10, this figure is reduced to 25%, and in people over 50 years old — up to 15%.
Studies have shown that in the first 2.5 years, the child’s brain grows very quickly. It is during the REM phase, when a person sees vivid dreams, that the young brain is busy forming new synapses (contacts between neurons), building and developing nerve networks. And after reaching 2.5 years, the body switches from building the brain to maintaining its work and repairing damage, including cleaning the brain of biological “garbage”. Lack of sleep does not fully restore the brain, which increases the risk of developing neurodegenerative diseases.