Sea-sickness

Sea Sickness

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Sea-sickness

Seasickness is a form of motion sickness

Motion sickness

Motion sickness or kinetosis is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement....
characterized by a feeling of nausea

Nausea

Nausea is the sensation of unease and discomfort in the stomach with an urge to vomit....
and, in extreme cases, vertigo

Vertigo (medical)

Vertigo is a specific type of dizziness, a major symptom of a balance disorder. It is the sensation of spinning or swaying while the body is actually stationary with respect to the surroundings....
experienced after spending time on a craft on water

Water

Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or States of matter, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam....
. It is typically brought on by the rocking motion of the craft. Some people are particularly vulnerable to the condition with minor stimulus and will feel seasick simply by setting foot on a boat, even if the vessel is in dry dock

Dry dock

A drydock is a narrow basin or vessel that can be flooded to allow a load to be floated in, then drained to allow that load to come to rest on a dry platform....
, while others are relatively immune, or become immune through exposure.Some people have even claimed experiencing sea sickness while watching nautical themed television programs.

Seasickness can be a debilitating condition and can be dangerous if the sufferer has an important role to carry out, such as steering a yacht

Yacht

A yacht is a recreational boat. It designates two rather different classes of watercraft, sailing and power yachts. Yachts are differentiated from working ships mainly by their leisure purpose....
through stormy seas while avoiding rocks and other hazards.

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Encyclopedia

Seasickness is a form of motion sickness

Motion sickness

Nausea

Nausea is the sensation of unease and discomfort in the stomach with an urge to vomit....
and, in extreme cases, vertigo

Vertigo (medical)

Water

Dry dock

Yacht

Vomiting

Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Undesired vomiting may result from many causes, ranging from gastritis or poisoning to brain tumors, or elevated intracranial pressure....
, are at increased risk of decompression illness

Decompression illness

Decompression Illness is a term generally used to describe illness after a decrease in the ambient pressure that a body is exposed to. Decompression Illness is usually experienced by divers, but it is not limited to diving in water....
.

Cause

Human beings instinctively seek to remain upright by keeping their centre of gravity over their feet. The most important way this is achieved is by visual reference to surrounding objects, such as the horizon

Horizon

The horizon is the apparent line that separates earth from sky.More precisely, it is the line that divides all of the directions one can possibly look into two categories: those which intersect the Earth's surface, and those which do not....
. Seasickness often results from the visual confusion on a moving craft, when nearby objects move with the motion of the craft. Because the lines of the masts

Mast (sailing)

The mast of a sailing ship is a tall, vertical, or near vertical, spar, or arrangement of spars, which supports the sails. Large ships have several masts, with the size and configuration depending on the style of ship....
, window

Window

File:OldShipWindows.jpgA window is an opening in a wall that allows the passage of light and, if not closed or sealed, air and sound. Windows are usually glazed or covered in some other transparency or translucent material....
s, and furniture

Furniture

Furniture is the mass noun for the movable objects which may support the human body , provide storage, or hold objects on horizontal surfaces above the ground....
on a ship are constantly shifting with respect to fixed references, humans, especially those unaccustomed to being at sea, can suffer a number of afflictions.

Sea-sickness has such a remarkable effect because both the sense of sight and touch are disturbed by the motion of a craft on water. The severity of seasickness is also influenced by the irregular pressure of the bowels against the diaphragm

Diaphragm

Diaphragm may refer to any of the following:Anatomy* Thoracic diaphragm, a tissue of muscle separating the thorax and abdomen of mammals...
as they shift with the rising and falling of the ship.

In his book The Human Body, Isaac Asimov

Isaac Asimov

Isaac Asimov , was a Russian-born United States author and professor of biochemistry, best known for his works of science fiction and for his popular science books....
related the anecdote about a seasick passenger whom a steward

Chief Steward

A Chief Steward is the senior unlicensed crew member working in the Steward's Department of a ship. Since there is no purser on most ships in the United States Merchant Marine, the steward is the senior person in the department, from whence its name....
cheerfully assured that nobody ever died from seasickness. The passenger muttered, "Please--it's only the hope of dying that's keeping me alive."

Many experience similar effects while not at sea:

in railway carriages
in automobile
Automobile

An automobile or motor car is a wheeled motor vehicle for transportation passengers, which also carries its own car engine or motor. Most definitions of the term specify that automobiles are designed to run primarily on roads, to have seating for one to eight people, to typically have four wheels, and to be constructed principally f...
s
on swing
Swing (seat)

A swing is a hanging seat, usually found in a playground for children, a circus for acrobats, or on a porch for relaxing. The seat of a swing can be attached to a chain or a rope....
s
while looking from a lofty precipice where known objects, being distant, are viewed under a new aspect and not so readily recognised
while walking on a wall
Wall

A wall is a usually solid structure that defines and sometimes protects an area. Most commonly, a wall delineates a building and supports its superstructure, separates space in buildings into Room s, or protects or delineates a space in the open air....
or roof
Roof

A roof is the covering on the uppermost part of a building. A roof protects the building and its contents from the effects of weather. Structures that require roofs range from a letter box to a cathedral or stadium, dwellings being the most numerous....
while looking directly up to a roof
while observing the stars in the zenith
Zenith

In broad terms, the zenith is the direction pointing directly above a particular location . Since the concept of being above is itself somewhat vague, scientists define the zenith in more rigorous terms....
on walking into a round room, where there are no perpendicular lines of light and shade and the walls and ceiling are covered with an irregularly-spotted design
on twirling round, as in waltzing
while watching video captured by an unsteady camera

Prevention and remedy

Over-the-counter and prescription

Prescription drug

A prescription drug is a medication that is regulated by legislation to require a medical prescription before it can be obtained. The term is used to distinguish it from over-the-counter drugs which can be obtained without a prescription....
medication

Medication

A pharmaceutical drug, also referred to as medicine or medicament, can be loosely defined as any substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease....
s such as dramamine and scopolamine

Scopolamine

Scopolamine, known by the names levo-duboisine and hyoscine, is a tropane alkaloid Medication with muscarinic antagonist effects. It is obtained from plants of the family Solanaceae , such as henbane, jimson weed and Angel's Trumpets , and corkwood ....
(as transdermal patches and tablets) are readily available though SCUBA divers must evaluate the risks versus the benefits. Ginger

Ginger

Ginger is a spice which is used for cooking and is also consumed whole as a delicacy or medicine. It is the rhizome of the Zingiber, Zingiber officinale....
capsules are also considered effective in preventing motion sickness. Some sufferers find that wearing special wristbands helps stave off the condition.

Those suffering from seasickness who are unaccustomed to the motion of a ship often find relief by:

keeping one finger over one ear (blocking one ear). This stops the balancing liquid near your ears from moving around, therefore stopping the brain from detecting any motion sickness
keeping their mind occupied
taking anti-seasickness/nausea capsules
keeping their eyes directed to the fixed shore or horizon, where possible
lying down on their backs and closing their eyes
drinking any substance that is likely to temporarily diminish their senses of sight and touch
using THC
THC

The acronym THC has several possible meanings:* Tetrahydrocannabinol, the main active chemical compound in Cannabis* Toronto Hemp Company, the world's largest Hemp and Cannabis Culture store, located in Toronto, Canada....
(where legal) or narcotics, which act through neural suppression, thus diminishing the all of the senses, and directly reducing the feeling of nausea (unfortunately, judgment may also be influenced).
move into a position where fresh air is blowing on their face
sucking on crystallized ginger
Ginger

Ginger is a spice which is used for cooking and is also consumed whole as a delicacy or medicine. It is the rhizome of the Zingiber, Zingiber officinale....
, sipping ginger tea or taking a capsule of ginger.
moving to the boat's center of gravity to eliminate motion due to pitch, roll and yaw
Tait-Bryan angles

Yaw, pitch, and roll, also known as Tait?Bryan rotations, named after Peter Guthrie Tait and George Bryan, are a specific sequence of Euler angles very often used in aerospace applications to define the relative orientation of a vehicle....
(but not translation
Translation (physics)

In physics, translation is movement that changes the displacement of an object, as opposed to rotation. For example, according to Whittaker:...
): see SS Bessemer
SS Bessemer

The SS Bessemer was an experimental Victorian era English Channel passenger paddle steamer with a swinging cabin, a concept devised by the engineer and inventor Henry Bessemer, intended to combat seasickness....
.
wearing an anti-nausea wristband, or otherwise stimulating the P6 acupressure point (on the inside of the forearm, three fingers' width down from the wrist crease)
taking the helm of a yacht can reduce sickness as the sufferer has something to concentrate on, and can also anticipate the movement of the vessel
sipping Coke or Pepsi (the phosphoric acid in them settles a sea-sick stomach)

Sea-sickness

Cause

Prevention and remedy

See also