Limitless - Jim Kwik Page 0,53
the brain tasked with more complex thought takes a back seat.”9
With such clear evidence that stress can be debilitating to your brain, finding ways to reduce or avoid stress becomes critical. I’m going to offer a number of suggestions in this area over the course of this book.
KWIK START
What is your favorite thing to do to cope with stress? When was the last time you did it?
10. SLEEP
If you want better focus, you need to get good sleep. If you want to be a clearer thinker, you need to get good sleep. If you want to make better decisions or have a better memory, you need to get good sleep. According to the National Institutes of Health:
Quality sleep—and getting enough of it at the right times—is as essential to survival as food and water. Without sleep you can’t form or maintain the pathways in your brain that let you learn and create new memories, and it’s harder to concentrate and respond quickly. Sleep is important to a number of brain functions, including how nerve cells (neurons) communicate with each other. In fact, your brain and body stay remarkably active while you sleep. Recent findings suggest that sleep plays a housekeeping role that removes toxins in your brain that build up while you are awake.10
The takeaway: getting enough sleep—and getting enough quality sleep—is essential if you’re going to make the most of your brain.
Sleep Is Not a Choice
I know there are lots of people out there who say they don’t need a lot of sleep, or that they don’t have time for sleep, or even consider it a point of pride that their lives are so full of activity that they “have no choice” but to sacrifice sleep. That’s a mistake, and, if you’re one of these people, it’s something I want you to reconsider right now.
“Sleep is crucial to overall health and daily functioning,” writes Dr. Jean Kim, a psychiatrist and a clinical assistant professor of psychiatry at George Washington University. “Increasing evidence has tied lack of sleep to a host of mental and physical disorders, including increased depression, irritability, impulsivity, cardiovascular disease, and more. One study noted that sleep actually functions as a sort of laundry cycle for the brain, where during sleep, blood vessels (and lymphatic channels) in the brain hyperperfuse and flush out metabolic buildup from the day and remove neurotoxins and distribute components that enhance cellular repair.”11
In his TED talk about sleep, Dr. Jeff Iliff of Oregon Health and Science University takes the “laundry cycle” metaphor even further. He notes that, while we’re awake, the brain is so busy doing other things that it doesn’t have the capacity to clean itself of waste. The buildup of this waste, amyloid-beta, is now being linked to the development of Alzheimer’s disease.
“When the brain is awake and is at its most busy, it puts off clearing away the waste from the spaces between its cells until later, and then, when it goes to sleep and doesn’t have to be as busy, it shifts into a kind of cleaning mode to clear away the waste from the spaces between its cells, the waste that’s accumulated throughout the day.”12
A little later in the talk, Iliff warns against doing something that so many of us do: sacrificing sleep until we get a chance to catch up. “Like our housework, it’s a dirty and a thankless job, but it’s also important. In your house, if you stop cleaning your kitchen for a month, your home will become completely unlivable very quickly. But in the brain, the consequences of falling behind may be much greater than the embarrassment of dirty countertops, because when it comes to cleaning the brain, it is the very health and function of the mind and the body that’s at stake, which is why understanding these very basic housekeeping functions of the brain today may be critical for preventing and treating diseases of the mind tomorrow.”13
So, if you’re one of the many people who have convinced themselves that there’s a level of nobility in getting by with minimal sleep, it’s time to revise your thinking. There’s simply too much to gain from a good night’s sleep (including what you can learn from your dreams).
Getting through the Night
It’s one thing to say you’re going to get a good night’s sleep. It’s another thing entirely to accomplish it. About a quarter of all Americans experience some level of insomnia every year.14
There is, however, very strong evidence connecting exercise to sleep, even among