Professor Juan Antonio Madrid has explained that sleeping "cleans the brain" thanks to the action of the glymphatic system, which facilitates the elimination of metabolites such as beta-amyloid, linked to the development of Alzheimer's. At the same time, sleep consolidates memory, helps process emotions and contributes to enhancing creativity.
During a conference promoted by the Real Academia de San Quirce and the Fundación Lilly, Madrid has warned about the consequences of exposure to artificial light during the night, which reduces the secretion of melatonin —the so-called chemical darkness— and causes a delay in falling asleep.
"We live in a world for which we are not biologically prepared, we go from gatherers exposed to natural light to spending the day in front of screens and sleeping in artificial environments. Recovering habits compatible with our biology, respecting circadian rhythms, reducing nocturnal blue light and valuing sleep is key for physical and mental health," Madrid stated.
Along these lines, the specialist has emphasized that human beings spend between 25 and 30 years of their existence sleeping. "To think that this is not fundamental to our health, our mood and our way of being is a mistake," he pointed out.
The researcher has also pointed out that almost all organisms with a complex nervous system sleep, from bees to octopuses, which exhibit patterns comparable to human REM sleep. In marine mammals such as dolphins, the so-called unihemispheric sleep allows them to rest while retaining the consciousness necessary to breathe and protect themselves from predators.
Madrid has also reviewed some milestones in sleep science: the pioneering experiments of the Russian researcher Marie Manaseina at the end of the 19th century, which demonstrated that lack of sleep is fatal before the absence of food, and the identification of REM sleep in 1953 by Eugene Aserinsky and Nathaniel Kleitman, after observing rapid eye movements in a child.
Finally, the professor has detailed that there are two main modalities of sleep. NREM or deep sleep, largely responsible for physical recovery and accounting for around 70% of the total, and REM, in which brain activity is very intense, the most vivid dreams appear, and emotions and memories are integrated. Both types alternate in cycles that repeat approximately every 90-120 minutes.