Virtually anyone can be
subject to sea sickness or motion sickness. In fact, 90% of the people
have had motion sickness at one point in their lives and only veteran
ocean sailors seem rather impervious to it.
Cause of seasickness
Motion sickness relates to our
sense of spatial orientation, which tells the brain where the body is "in
space": what direction it is moving, what direction it is pointing, and if
it is turning or standing still.
This sense of spatial orientation is regulated by complex interaction of
the 4 following mechanisms:
- Both inner ears
monitor the directions of motion in three dimensions.
- Our eyes observe
where our body is in relation to its surroundings as well as the
direction of motion.
- Skin pressure
receptors such as those located in the feet and seat sense in what
direction the gravitational pull affects our body, in other words: what
side is up?
- Muscle and joint
sensory neural receptors report which parts of the body are in
motion and in which relative direction.
All these sensory data will subsequently be processed in the central
nervous system, which enables us to balance, move and position ourselves
properly in our three dimensional surroundings.
The symptoms of motion sickness appear when the brain receives
conflicting messages from the 4 systems. And a conflict on board can
easily occur : when reading a book on deck your eyes observe no motion,
yet your inner ears feel the motion of the yacht due to the waves.
Symptoms
The first
telltales of such a conflict are often lethargy and a slight drowsiness.
But for the victims it will usually start with a nauseous feeling and/or a
slight cold sweat. Then these symptoms increase, and the face becomes
paler, perhaps even greenish. Any attempt to concentrate on a task will
worsen this predicament. The nauseous feeling eventually becomes
incontrollable, and leads to - sometimes violent - vomiting.
Prevention
Hours before
casting off you could well use an over-the-counter antihistamine such as
meclizine or dimenhydrinate and you should - before ánd during the voyage
- avoid spicy or rich foods, alcohol and apples. For longer trips, a
prescription medication called Transderm-Scopolamine patch can be worn
behind the ear for up to three days at a time. Side-effects of these
medications usually consist of sedation and dry mouth. Interestingly
enough : Recent studies have shown that ginger root may be as effective as
the other drug treatments but is associated with fewer side effects.
If, despite all these precautions, you still notice the early symptoms
with one of you crew, act immediately and :
- Get the victim out on
deck but not in direct sunlight.
- Don't give the victim
any task other than steering.
Steering - as well as studying the horizon works and will help to
anticipate the boat's motion.
- Steady the yacht, either
by heaving to or letting the best helmsman drive the yacht.
The Gundogan usually has
medicines onboard to counteract sea sickness.
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