Biomedical Engineering Reference
In-Depth Information
Case 1
As soon as the oil escaped from the cooler, stress levels reached a peak
within seconds. The first reaction was to fight the problem and to try
to reinstall the valve. When this didn
t work, the brain went into flight
mode and issued to run away as quickly as possible. This flight was
fully intuitive, and on familiar ground, the right route would have
been chosen. In a strange environment, however, one starts to run
without any plan. If there had been possible dangers in running away,
this should have been trained in advance, because once high stress is
reached, there is hardly any prospect for coaching.
Case 2
When the weather conditions are around freezing point, the surface of
a road can be suddenly very slippery. As soon as a driver experiences
that the car is losing grip and is heading for an obstacle, the stress level
rises very fast. All normal reflections on how to drive are lost, and
impulsive steering becomes the case. If the car is not reacting quickly
due to ice on the road, this impulsive steering can lead to an overreac-
tion, steering too fast away from the obstacle. The trip can end on the
other side of the road. Only a special course for driving under extreme
weather conditions can help to avoid this kind of overreaction.
6.2.2 Regulating Alertness
We have seen that each task has an optimum level of brain activity.
For risk detection, the optimum would be around 25 hertz. To reach
this optimum level, the brain has developed several ways of regulating
the activity level. We speak of activating and deactivating systems. To
some degree, each person permanently regulates his own system, but
there are also circumstances that directly influence the activity of the
brain. The brain can respond to external challenges and also assimilate
to the activity level of the people involved in a task. Stressed people
can make you more stressed; relaxed people can make you more at
ease. We will now discuss several activating and deactivating systems.
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External pressure increases alertness.
