The Sleep Debt
The Sleep Debt
Getting too little sleep creates a "sleep debt" -
being overdrawn at a bank. Eventually, our body will demand that the debt be
repaid, until which time our judgment, reaction time, and other functions are
Can we learn to sleep less? –
the majority of people who are lacking sleep
don’t think as well and make mistakes. The few people who really can do
with only a few hours of sleep without detracting from their performance did not
learn how to do that, they were born that way.
Accumulated lost sleep must be paid back - Most people need 7-9 hours of sleep a
night, NOT COUNTING the time it takes to fall asleep. The brain keeps a tally of
the amount of sleep you have had over at least the past couple weeks (longer
times have not been studied). If you have not had enough sleep, your tendency to
fall asleep is increased. But will be decreased when you start paying back the
sleep debt to your body. If someone who needs 8 hours of sleep gets only 6 hours
of sleep a night, after five days they owe their body 10 hours sleep, which is
not made up by sleeping in on the weekend.
The time it takes you to go to sleep is in direct
proportion to your sleep debt -
if you fall
asleep without caffeine faster than 15-20 minutes, you are sleep deprived.
If you fall asleep within 5 minutes you are severely sleep deprived. 10
minutes is borderline.
Short naps don’t make much difference to sleep
the body wants full sleep cycles of at least ~ 1 ½ hours.
“Early to Bed” takes a change in lifestyle -
Turn off the TV and go to bed earlier every night to get more sleep
on a regular, ongoing basis.
Sleep debt makes us feel lousy and act
obnoxiously – in contrast, good
sleep improves mood and feelings. However, we often don’t realize that it
is lack of sleep causing the bad feelings because “Clock-dependent
alerting” masks this effect at certain times of
Lack of Sleep / Sleep debt can dangerously impair
brain functions –
after 40 years of study, Dement concluded that
sleep debt is the most important factor in the quality or excellence of
psychological and cognitive function. When we are sleep deprived, cognition
functions are one of the first to go. In addition, once you repay
your sleep debt, you may find that people or things that you previously found
dull and uninteresting are now in fact interesting.
Examples of effects of sleep debt:
The Exxon Valdez disaster
worst accidental oil spill, BP oil spill was the largest) – final report
identified severe sleep-deprivation
of a 3rd mate as the main cause of the disaster. The captain had
handed over command to the 3rd mate and left the bridge. The 3rd
mate had slept only 6 hours in the previous 48. Recognizing the danger of a
collision with a reef, he ordered the ship to starboard but did not notice that
the autopilot was still on and that the ship had not turned. Twice lookouts
warned the 3rd mate about the position of lights marking the reef,
but unable to interpret the danger in what they said, he didn’t check or
register why the ship had not turned. Finally, when he realized
that the copilot was turned on, it was too late.
Space shuttle Challenger
the final report found to have been due to mistakes made by the
NASA manager experiencing severe sleep deprivation;
American Airlines flight
in South America flew into a mountain and killed 149 people - because the pilot was so sleepy that he pressed the wrong button
accidents in hospitals - related to sleep
Traffic accidents many
times involve sleep-deprived teenagers or adults at the wheel –
a sleep debt
greatly increases the effects of alcohol.
Impaired Performance -
researchers found that after 17 hours awake, at 1.00 am, a sleep-deprived group
had the same test scores as drinking volunteers who had blood-alcohol levels of
0.05 %. After 24 hours awake, the sleep-deprived group had the same
coordination deficits as those with blood-alcohol levels of 0.1 %:
Ability to think/concentrate diminished
Difficulty situating oneself in time and
Hallucinations similar to when falling
asleep (midway between reality and dreaming) -
which can be fatal at work or driving
Impaired Creativity - After decades of study, Rothenberg found that
motivation is a common trait in highly
creative people, and he demonstrated that almost all creative acts come
after long sustained perseverance.
Dement found that motivation is one of the
first things to go when sleep is shortchanged.
Chronic health problems -
lack of sleep disturbs regulatory mechanisms that are normally at
work during the night. Typical problems include obesity, diabetes, and high
If we have sleep debt, why aren’t we sleepy all day long? -
Another mechanism, the biological clock, works
to wake you up at specific times.
Two main times when
your body clock will make you extra alert are:
In the morning when you wake up
Very late afternoon, around 6 pm, with the peak
at possibly 9 pm – possibly this energy is
meant for healing and we are meant to be in bed. If you have a serious health
pain or problem - get to bed by 7pm, and if you wake up at 4 am - get up and
start your day (This does not apply to teenagers, who are meant to go to bed
late and sleep in).
Wakefulness is at its
lowest around mid day –
the time when many societies traditionally took (or still take) a