The effects of rapid
travel on the body are actually far more disturbing than we realize. Jet Lag is
not a psychological consequence of having to readjust to a different time zone.
It is due to changes in the body’s physiological regulatory mechanisms,
specifically the hormonal systems, in a different environment.
Now that we understand what Jet Lag is, we can go some way to overcome it. A
great number of the body’s events are scheduled to occur at a certain time of
day. Naturally these have to be regulated, and there are two regulatory systems
which interact.
One
timing system comes from the evidence of our senses and stomachs, and the
periodicity we experience when living in a particular time zone. The other
belongs in our internal clocks (the major one of which may be physically
located in a part of the brain called the suprachiasmatic nucleus) which, left
alone, would tie the body to a 25-hour rhythm. Normally the two timers are in
step, and the surroundings tend to regularize the internal clocks to the more
convenient 24-hour period.
If, however, you move the whole body to a time zone which is four hours
different, the two clocks will be out of step, like two alarm clocks which are
normally set together, but which have been reset a few hours apart. Whereas the
two clocks would normally sound their alarms together, now they ring at
different times. Similarly, the body can be set for evening while the sun is
rising.
In time the physiological system will reset itself, but it does take time. One
easily monitored rhythm is palm sweating. A man flown to a time zone different
by 10 hours will take eight days to readjust his palm sweat. Blood pressure,
which is also rhythmical, takes four days to readjust.
What can we do about
it? It is not feasible to wait four days until the body is used to the new time
zone. Fortunately there is a short cut. It relies on two things-the power of
the stomach to regulate the timing of other events, and the pharmacological
actions of coffee. The basic assumptions are:
Coffee delays the body
clock in the morning, and advances it at night. Coffee at mid-afternoon is
neutral. Protein in meals stimulates wakefulness, while carbohydrates promote
sleep. Putting food into an empty stomach helps synchronize the body clock.
46. What is jet lag
associated with?
A. Psychological
change. B.
Physiological change.
C. Inexperience
of rapid travel. D. Unfamiliar environment.
47. What helps us to
adjust to a 24-hour rhythm?
A. Alarm
clock. B.
Suprachiasmatic nucleus in our brain.
C. Signals from
outside of the body. D. Our senses and stomachs.
48. What do we know
from the fifth paragraph?
A. A person
moving to a different time zone will suffer from high blood pressure.
B. A person
moving to a different time zone will sweat a lot.
C. Moving to a
different time zone will affect both palm sweat and blood pressure.
D. If the rhythm
of blood pressure and palm sweat are not in step, there will be jet lag.
49. What should we do
if we want to stay awake?
A. To take
coffee at three o’clock in the afternoon.
B. To have meals
that contain lots of protein.
C. To have some
carbohydrate drinks.
D. To stop
putting food into our stomach.
50. How can we cure jet
lag?
A. To
sleep for days. B. To wait for self-recovery.
C. To
drink tea. D. To
get something to eat.