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Seasickness

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This redirect is about the type of motion sickness. For Seasick, see Seasickness (disambiguation).
Seasickness
SpecialtyEmergency medicine, neurology Edit this on Wikidata

Seasickness is a form of motion sickness characterized by a feeling of nausea and, in extreme cases, vertigo, experienced after spending time on a craft on water.[1] 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, while others are relatively immune, or become immune through exposure.[1] 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 through stormy seas while avoiding rocks and other hazards.[1] It is also particularly hazardous for scuba divers[2] who, through dehydration following vomiting, are at increased risk of decompression illness.

Cause

Human beings instinctively seek to remain upright by keeping their center of gravity over their feet. The most important way this is achieved is by visual reference to surrounding objects, such as the horizon. 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, windows, and furniture 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 as they shift with the rising and falling of the ship.

In his book The Human Body, Isaac Asimov related the anecdote about a seasick passenger whom a steward 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 automobiles
  • in aircraft
  • on swings
  • 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 or roof
  • while looking directly up to a roof
  • while observing the stars in the zenith
  • 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
  • Ski sickness whilst skiing with very poor visibility

Prevention and remedy

Over-the-counter and prescription medications such as dramamine,[3] scopolamine[4] and promethazine[5] (as transdermal patches and tablets) are readily available. As these medications often have side effects, anyone involved in high-risk activities while at sea (such as SCUBA divers) must evaluate the risks versus the benefits.[6][7][8][9] Promethazine is especially known to cause drowsiness, which is often counteracted by ephedrine in a combination known as "the Coast Guard cocktail."[10]

Ginger capsules are also considered effective in preventing motion sickness.[11] Some sufferers find that wearing special wristbands helps stave off the condition.[12][13]

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

  • 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 (see Medical cannabis) 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, sipping ginger tea or taking a capsule of ginger.
  • moving to the boat's center of gravity to eliminate motion due to translation (but not pitch, roll and yaw): see SS Bessemer.
  • 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

See also

References

  1. ^ a b c Benson, Alan J. (2002). "Motion Sickness". Medical Aspects of Harsh Environments. Vol. 2. Washington, D.C.: Borden Institute. pp. 1048–1083. ISBN 978-0-16-051184-4. Retrieved 29 June 2009. {{cite book}}: External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help); Unknown parameter |editors= ignored (|editor= suggested) (help)
  2. ^ Norfleet WT, Peterson RE, Hamilton RW, Olstad CS (1992). "Susceptibility of divers in open water to motion sickness". Undersea Biomedical Research. 19 (1): 41–7. PMID 1536062. Retrieved 2009-07-16. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  3. ^ Weinstein SE, Stern RM (1997). "Comparison of marezine and dramamine in preventing symptoms of motion sickness". Aviation, Space, and Environmental Medicine. 68 (10): 890–4. PMID 9327113. {{cite journal}}: Unknown parameter |month= ignored (help)
  4. ^ Spinks AB, Wasiak J, Villanueva EV, Bernath V (2007). "Scopolamine (hyoscine) for preventing and treating motion sickness". Cochrane Database of Systematic Reviews. 18 (3): CD002851. doi:10.1002/14651858.CD002851.pub3. PMID 17636710. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  5. ^ "Phenergan information". Drugs.com. Retrieved 2009-07-10.
  6. ^ Schwartz, Henry JC and Curley, Michael D (1986). "Transdermal Scopolamine in the Hyperbaric Environment". United States Navy Experimental Diving Unit Technical Report. Retrieved 2008-05-09.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ Bitterman N, Eilender E, Melamed Y (1991). "Hyperbaric oxygen and scopolamine". Undersea Biomedical Research. 18 (3): 167–74. PMID 1853467. Retrieved 2008-05-09. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  8. ^ Williams TH, Wilkinson AR, Davis FM, Frampton CM (1988). "Effects of transcutaneous scopolamine and depth on diver performance". Undersea Biomedical Research. 15 (2): 89–98. PMID 3363755. Retrieved 2008-05-09. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  9. ^ Arieli R, Shupak A, Shachal B, Shenedrey A, Ertracht O, Rashkovan G (1999). "Effect of the anti-motion-sickness medication cinnarizine on central nervous system oxygen toxicity". Undersea and Hyperbaric Medicine. 26 (2): 105–9. PMID 10372430. Retrieved 2008-05-09.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. ^ East Carolina University Department of Diving & Water Safety. "Seasickness: Information and Treatment" (PDF).
  11. ^ Ernst E, Pittler MH (1 March 2000). "Efficacy of ginger for nausea and vomiting: a systematic review of randomized clinical trials". British Journal of Anaesthesia. 84 (3): 367–71. PMID 10793599.
  12. ^ Gahlinger PM (2000). "A comparison of motion sickness remedies in severe sea conditions". Wilderness & Environmental Medicine. 11 (2): 136–7. PMID 10921365.
  13. ^ Bertolucci LE, DiDario B (1995). "Efficacy of a portable acustimulation device in controlling seasickness". Aviation, Space, and Environmental Medicine. 66 (12): 1155–8. PMID 8747609. {{cite journal}}: Unknown parameter |month= ignored (help)
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