Why We
Sleep
✦
UNLOCKING THE POWER
OF SLEEP AND DREAMS
✦
Matthew Walker, PhD
WhyWeSleep_TO_1_circadian.pdf
1
5/11/17
10:27 AM
Figure 1: Typical Twenty-Four-Hour Circadian Rhythm
(Core Body Temperature)
Rectal Temperature (°C)
37.2
37.1
37.0
36.9
36.8
36.7
36.6
12 pm 4 pm 8 pm 12 am 4 am 8 am
Time (Twenty-Four Hours)
WhyWeSleep_TO_2_melatonin.pdf
1
5/11/17
10:29 AM
Figure 2: The Cycle of Melatonin
Melatonin (pg/mL plasma)
50
40
30
20
10
0
Noon
6 pm
WhyWeSleep_TO_3_effects.pdf
Midnight
Time
1
3/16/17
6 am Noon
10:40 AM
Figure 3: Effects of Various Drugs on Spider Web Building
Normal
LSD
Speed
Marijuana
Caffeine
2
Figure 4: The Two Factors Regulating Sleep and Wakefulness
Sleep reduces adenosine
(Decreasing sleep pressure, or Process-S)
Process-S
(Sleep drive)
Process-C
Circadian
(Wake drive)
sleep
11 pm
7 am
7 am
WhyWeSleep_TO_5_urge.pdf
1
5/11/17
sleep
11 pm 7 am
10:31 AM
Figure 5: The Urge to Be Awake
Strong urge to be awake
(Small distance between Process-C and Process-S)
Process-S
(Sleep drive)
Process-C
Circadian
(Wake drive)
sleep
11 pm
7 am
7 am
WhyWeSleep_TO_6_urgetosleep.pdf
1
5/11/17
sleep
11 pm 7 am
10:31 AM
Figure 6: The Urge to Sleep
Greatest urge to sleep
(Greatest distance between Process-C and Process-S)
Process-S
(Sleep drive)
Process-C
Circadian
(Wake drive)
7 am
sleep
11 pm
7 am
3
sleep
11 pm 7 am
WhyWeSleep_TO_7_ebbandflow.pdf
1
5/11/17
10:32 AM
Figure 7: The Ebb and Flow of Sleep Deprivation
Overpowering urge to sleep
Weak urge to sleep
Strong urge to sleep
Process-S
(Sleep drive)
Process-C
Circadian
(Wake drive)
7 am
awake
11 pm
7 am
WhyWeSleep_TO_8_architecture.pdf
awake
1
sleep
11 pm 7 am
3/16/17
10:48 AM
Figure 8: The Architecture of Sleep
Cycle 1
Cycle 2
Cycle 3
Cycle 4
Cycle 5
Wake
REM
NREM Stage 1
NREM Stage 2
NREM Stages 3 and 4
(Slow wave sleep)
11 pm
Midnight
1 am
2 am
3 am
4 am
5 am
Time of Night
WhyWeSleep_TO_9_brainwaves.pdf
1
3/16/17
10:49 AM
Figure 9: The Brainwaves of Wake and Sleep
Awake
Deep NREM sleep
REM sleep
50µV
1s
4
6 am
7 am
WhyWeSleep_TO_10_sportsinjury.pdf
1
3/14/17
10:46 AM
Figure 10: Sleep Loss and Sports Injury
% Chance of Injury
80
70
60
50
40
30
20
10
0
6hr
WhyWeSleep_TO_11_nba.pdf
7hr
8hr
Average Sleep
1
6/15/17
9hr
1:00 PM
Figure 11: NBA Player Performance
More than Eight Hours Sleep vs. Less than Eight Hours Sleep
+12% Increase in minutes played
+29% Increase in points/minute
+2% Increase in three-point percentage
+9% Increase in free-throw percentage
+37% Increase in turnovers
+45% Increase in fouls committed
WhyWeSleep_TO_12_car.pdf
1
3/16/17
10:51 AM
Figure 12: Sleep Loss and Car Crashes
11.5
Hours of Sleep
<4 Hr
4–5 Hr
4.3
1.9
5–6 Hr
6–7 Hr
1.3
x2
x4
x6
x8
Increase Crash Risk
5
x10
x12
WhyWeSleep_TO_13_obesity.pdf
1
3/14/17
11:26 AM
10 hr
35%
9 hr
30%
25%
8 hr
20%
7 hr
15%
6 hr
1960
1980
2000
Date
(Year)
WhyWeSleep_TO_14_memory.pdf
1
3/16/17
8:55
Obese Individuals (US)
Average Sleep Amount
Figure 13: Sleep Loss and Obesity
10%
1940
AM
Figure 14: Example of a Memory Association Network
UC Berkeley
Berkeley
California
Sun
Quake
Tsunami
Courses
Graduate
Job
Beach
Ocean
Money
WhyWeSleep_TO_15_sleepingpills.pdf
1
Sports
Academe
Knowledge
Stanford
Advance
6/15/17
1:03 PM
Rivalry
Odds Risk of Death
Figure 15: Risk of Death from Sleeping Pills
6X
5X
4X
3X
2X
(baseline) 1X
NONE ½–18 18–132 >132
Sleeping Pills Used/Year
6
Football
WhyWeSleep_TO_16_globalecon.pdf
1
3/16/17
8:24 AM
Figure 16: Global Economic Cost of Sleep Loss
(A) $450
(B) 3.5%
$411
$225
GDP
Billions (US $)
2.5%
$300
$138
$150
$75
$0
2.9%
3.0%
$375
$40
US
UK
2.3%
1.9%
2.0%
1.4%
1.5%
1.6%
1.0%
$60
0.5%
$21
0.0%
Canada Japan Germany
US
UK
Nation
Canada Japan Germany
Nation
WhyWeSleep_TO_17_intervention.pdf
1
3/16/17
9:11 AM
Figure 17: Levels of Sleep Intervention
Societal
Public Policy/
Government
Organizational
Educational/
Interpersonal
Individual
7