The typical pattern of response to emergencies probably
emerged during the time when all humans faced mostly
physical threats. Although the "threats" we now live with are
seldom physical, the body reacts as if they were: The pupils
dilate to let in more light. Sweat pours out, reducing the
chance of skin cuts. Blood vessels near the skin contract to
reduce bleeding, while those in the brain and muscles dilate
to increase the oxygen supply. The gastrointestinal tract,
including the stomach and intestines, slows down to reduce
the energy expensed in digestion. The heart beats faster,
and blood pressure rises.
Normally, people calm down when a stressful event is over
especially if they have done something to cope with it. For
instance, imagine your own reactions if you're walking
down a dark street and hear someone running toward you.
You get scared. Your body prepared you to ward off an
attacker or run fast enough to get away. When you do
escape, you gradually relax.
If you get angry at your boss, it's a different matter. Your
body may prepare to fight. But since you want to keep your
job, you try to ignore the angry feelings. Similarly, if on the
way home you get stalled in traffic, there's nothing you can
do to get away. These situations can literally may you sick.
Your body has prepared for action, but you cannot act.
Individuals differ in the way they respond to stress. In
some, one function, such as blood pressure, becomes more
active while others remain normal. Many experts believe
that these individual physical responses to stress can
become habitual. When the body is repeatedly aroused,
one or more functions may become permanently overactive.
Actual damage to bodily tissues may eventually result.
Biofeedback is often aimed at changing habitual reactions to
stress that can cause pain or disease. Many clinicians
believe that some of their patients and clients have forgotten
how to relax. Feedback of physical responses such as skin
temperature and muscle tension provides information to
help patients recognize a relaxed state. The feedback signal
may also act as a kind of reward for reducing tension. It's
like a piano teacher whose frown turns to a smile when a
young musician finally plays a tune properly.
The value of a feedback signal as information and reward
may be even greater in the treatment of patients with
paralyzed or spastic muscles. With these patients,
biofeedback seems to be primarily a form of skill training
like learning to pitch a ball. Instead of watching the ball, the
patient watches the machine, which monitors activity in the
affected muscle. Stroke victims with paralyzed arms and
legs, for example, see that some part of their affected limbs
remains active. The signal from the biofeedback machine
proves it. This signal can guide the exercises that help
patients regain use of their limbs. Perhaps just as important,
the feedback convinces patients that the limbs are still alive.
This reassurance often encourages them to continue their