Back in my early Microsoft days, I routinely pulled all-nighters when we had to
deliver a piece of software. Once or twice, I stayed up two nights in a row. I knew I
wasn’t as sharp when I was operating mostly on caffeine and adrenaline, but I was
obsessed with my work, and I felt that sleeping a lot was lazy.
Now that I’ve read Matthew Walker’s Why We Sleep, I realize that my all-nighters,
combined with almost never getting eight hours of sleep, took a big toll. The book
was recommended to me by my daughter Jenn and John Doerr. Walker, the director of
UC Berkeley’s Center for Human Sleep Science, explains how neglecting sleep
undercuts your creativity, problem solving, decision-making, learning, memory, heart
health, brain health, mental health, emotional well-being, immune system, and even
your life span. “The decimation of sleep throughout industrialized nations is having a
catastrophic impact,” Walker writes.
I don’t necessarily buy into all of Walker’s reporting, such as the strong link he claims
between not getting enough sleep and developing Alzheimer’s. In an effort to wake us
all up to the harm of sleeping too little, he sometimes reports as fact what science has
not yet clearly demonstrated. But even if you apply a mild discount factor, Why We
Sleep is an important and fascinating book.
Because this is a short review, I’ll answer a few questions that I suspect are top of
mind for you.
Does everyone really need seven or eight hours of sleep a night? The answer is that
you almost certainly do, even if you’ve convinced yourself otherwise. In the words of
Dr. Thomas Roth, of the Henry Ford Hospital in Detroit, “The number of people who
can survive on five hours of sleep or less without impairment, and rounded to a whole
number, is zero.”
Why do we sleep? After all, when you’re sleeping—and all animals do—you can’t
hunt, gather, eat, reproduce, or defend yourself. Yet Walker concludes that the
evolutionary upsides of sleep are far greater than these downsides. In brief, sleep
produces complex neurochemical baths that improve our brains in various ways. And
it “restocks the armory of our immune system, helping fight malignancy, preventing
infection, and warding off all manner of sickness.” In other words, sleep greatly
enhances our evolutionary fitness—just in ways we can’t see.
What can I do to improve my sleep hygiene?

Replace any LEDs bulbs in your bedroom, because they emit the most sleepcorroding blue light.

If you’re fortunate enough to be able to control the temperature where you live,
set your bedroom to drop to 65 degrees at the time you intend to go to sleep.
“To successfully initiate sleep … your core temperature needs to decrease by 2
to 3 degrees Fahrenheit,” according to Walker.

Limit alcohol, because alcohol is not a sleep aid, contrary to popular belief.
While it might help induce sleep, “alcohol is one of the most powerful
suppressors of REM [rapid-eye-movement] sleep,” Walker says.

If you can possibly take a short midday nap like our ancestors used to and some
Mediterranean and South American cultures still do, you should (but no later
than 3 pm). It will likely improve your creativity and coronary health as well as
extend your lifetime.
It took me a little longer than usual to finish Why We Sleep—ironically, because I kept
following Walker’s advice to put down the book I was reading a bit earlier than I was
used to, so I could get a better night’s sleep. But Walker taught me a lot about this
basic activity that every person on Earth needs. I suspect his book will do the same for
you.