TAIPEI (Taiwan News) – Loss of sleep is a silent, fatal epidemic, warned sleep expert and neuroscientist, Matthew Walker, at TED 2019, held in Vancouver this April.

Lack of sleep hurts you in real ways, said Walker, a professor of neuroscience and psychology at the University of California, Berkeley. It makes you unable to learn new things, more vulnerable to dementia, dumber, and more forgetful.

Sleep deprivation weakens your learning abilities because it hinders activities in the hippocampus, our “informational inbox” as Walker terms it, which turns experiences into long-term memories.

“You need sleep after learning, to essentially hit the save button on those new memories so you don’t forget,” said Walker. “But recently we’ve discovered that you also need sleep before learning to actually prepare your brain. Almost like a dry sponge ready to soak up new information.”

Without sleep, “the memory circuits of the brain essentially become waterlogged,” stopping you from absorbing new information, explained Walker.

Your immune system also suffers when you do not sleep enough. Research shows the activity level of natural killer cells in the immune system could decrease by 70 percent when you sleep only four hours at night. “That’s a concerning state of immune deficiency,” said Walker.

Moreover, sleep loss disrupts the creation of sex hormones, like estrogen and testosterone. Men who sleep five hours a night have significantly smaller testicles than men who sleep seven hours or more.

“The decimation of sleep throughout industrialized nations is having a catastrophic impact on our health, our wellness, even the safety and education of our children. It’s a silent sleep loss epidemic. It’s fast becoming one of the greatest challenges we face in the 21st century,” said Walker in his 20-minute TED talk.