After driving for about six hours, a trucker decides to pull over
and sleep for a little while. As soon as he falls asleep, he is awoken
by some knocks on the door of his cab. “Can you tell me the time,
please?” asks a jogger. “Yeah, it’s 4:30,” answers the trucker. He
falls asleep again, but he is awoken again by knocks on his cab. It’s
another jogger who asks the time. “It’s 4:40!” yells the trucker.
Deciding he didn’t want to be disturbed any more so he could get some
sleep, he writes on a piece of paper: I DON’T KNOW THE TIME and sticks
the paper in his windshield. Well, he gets to sleep again but before
you know it, he is again awakened by knocks on his cab. It’s another
jogger, who says, “It’s 5:25”. J
For some of us getting to sleep is much like this trucker who seems
to be having trouble. For others of us, not sleeping has become a way
of life. Today I want to talk about some concepts related to sleep and
highlight some information to streamline your sleep life, no, not your
sex life, for the best benefits to your health.
Sleep is perhaps the most important predictor of how long you will
live. In a study by the American Cancer Society, a person’s habitual
sleep time was best correlated with mortality. The highest mortality
was found in people who slept four hours or less and in those that
slept more than nine hours or more. The lowest mortality was found in
those who regularly slept eight hours a night.
The average American has about 25 hours of sleep debt. Sleep debt is
the number of hours we owe to the sleep bank if we don’t get a usual 8
hours a night. We generally owe the bank hour for hour when we sleep
less than 8 hours a night.
The way they figured the average sleep debt is that they put some
people in a totally dark place for 7 days straight, 24 hours a day. At
first the subjects, I call them victims J , slept more than 8 hours for
each 24 hours, but eventually they got back to a natural schedule of 8
hours of sleep a night by the seventh day. On the average, each subject
repaid 25 hours of sleep before they returned to the usual 8 hours a
night. Consider what your sleep debt might be and understand that 50
hours of sleep debt is about the upper limit of what a person can
withstand before you are unable to properly function and put yourself
are in danger, driving or otherwise.
A fun way of measuring your own sleep debt can be done by yourself.
Lay down with your eyes closed and turn the lights low or draw the
curtains. Put one hand over the edge of the bed and hold a metal spoon
with a plate on the floor below you. Check the clock before you settle
into bed. When you fall asleep, you will be awakened by the metal spoon
falling on the plate. This tells you your sleep latency or how long it
takes for you to fall asleep. Sleep latency is correlated with your
level of sleep debt. If it takes 15-20 minutes to fall asleep, you are
optimally rested. If you fall asleep within 5 minutes, you are
seriously sleep deprived or sleep disordered. 10-15 minutes of sleep
latency means you can afford to work off some sleep debt; 5-10 minutes
of sleep latency means you are certainly troubled with sleep debt.
Because one’s sleep latency depends on the time of day that you measure
it, the lowest score on any given day, if you tested yourself several
times, is most likely your true sleep latency.
The reason sleep latency varies throughout the day is that there is
something called clock-dependent alerting. First let me explain sleep
homeostasis, sleep what? J . You could just call it your sleep drive.
For every two hours that you are awake, your body will want to sleep
one hour to compensate for being awake. The longer you are awake, the
stronger is your sleep drive. This sleep drive is continuously active.
In contrast, there is a drive to be awake that is related to our
biological clocks within us; i.e., we have a clock that regulates our
body chemistry and drives us to stay awake, which is called
clock-dependent alerting or our wakefulness drive. This drive is active
during the morning, takes a slump in the afternoon, then is turned on
again around 4-5 PM and slowly dies down when nightfall comes. The
after lunch slump that we attribute to eating a sumptuous meal is
largely due to this slump in our clock-dependent alerting that is not
active during that time of day. You could say then that our level of
sleepiness at any given time of day is a combination of: 1) our sleep
debt, 2) our clock-dependent alerting, and 3) the stimulation from the
environment around us.
You can monitor your daily sleep need by watching your daytime
sleepiness in relation to how much you’ve been sleeping. The more you
seem sleepy, the more you need to sleep at night. If you’re having
trouble staying awake for my stimulating talk, you need to get more
sleep at night J .
Daytime fatigue is the most common single sleep symptom that people
complain of. In a recent National Sleep Foundation survey, 75% of
people said they were obtaining enough sleep, but also regularly
experienced daytime sleepiness and fatigue. More than half the time, if
you have daytime fatigue, you’ll have some kind of sleep disorder. In
most cases, you could assume to have obstructive sleep apnea until
proven otherwise. Obstructive sleep apnea is a condition in which your
physical features get in the way of you being able to breathe properly
when you sleep. This could be caused by large tonsils, simple obesity,
or just a small airway.
If you snore and are tired during the day, especially consider that
you have obstructive sleep apnea. Your chances of having sleep apnea
are more likely if you are overweight and you wake up with a sore
throat and/or a headache. You must get a sleep study to definitively
determine if you have sleep apnea, especially if you already have high
blood pressure or any heart problem because sleep apnea can aggravate
these conditions.
One way you can yourself check if you have sleep apnea is to record
your sleep sounds while you sleep. A simpler way is to ask your bed
partner if you snore. There is help for sleep apnea in the form of what
is called CPAP, continuous positive airway pressure. You may have to
sleep with a mask delivering air under pressure.
Thus far, we’ve talked about the importance of sleep to your health.
We’ve explained sleep debt, sleep latency, sleep homeostasis,
clock-dependent alerting, and obstructive sleep apnea. In closing, I
just want to leave you with some tips on for sleeping right that you
can incorporate in your lifestyle:
Avoid caffeine in the evenings for obvious reasons.
Avoid eating 3 hours before you go to bed.
Have a regular bedtime and have a regular bedtime ritual to condition yourself to sleep easier.
Take care of your surroundings to insure restful sleep: noise, temperature, comfortable bed and pillow, proper night clothes
Consider
taking a power nap when you are tire but need to be alert. A 45 minute
nap can lead to 6 hours of alertness after the nap. A one-hour nap can
give you 10 hours of alertness afterwards.
For traveling, change
your watch to your destination’s time zone 1-2 days before your trip.
Assuming you are traveling east, like most of us might do, in
preparation for your trip, get direct sunlight as soon as you can each
day by drawing your curtains. You can also take some Melatonin, 3 mg,
late in the evening to advance your biological clock. Also if you
travel east, schedule meetings late in the day so you can adjust
easier. If traveling east, take no nap during your plane flight so that
you sleep early at your destination.
I hope my talk has given you
some mental stimulation just when your clock-dependent alerting is in a
slump. In any case, you know I’ll understand. Just snooze and you won’t
lose.