Motion sickness

Motion sickness is the uncomfortable dizziness, nausea, and vomiting that people experience when their sense of balance and equilibrium are disturbed by constant motion. Motion sickness is a common problem, with nearly 80% of the population enduring its affects at one time in their lives. While it may occurat any age, motion sickness most often afflicts children over the age of two, with the majority outgrowing their susceptibility.

When looking at why motion sickness occurs, it is helpful to understand the role of the sensory organs. The sensory organs control a body's sense of balance by telling the brain what direction the body is pointing, the direction itis moving, and if it is standing still or turning. These messages are relayed by the inner ears, the eyes, the skin pressure receptors (such as in thosein the feet), and the muscle and joint sensory receptors. The central nervoussystem (the brain and spinal cord) is responsible for processing all incoming sensory information.

Motion sickness and its symptoms surface when conflicting messages are sent to the central nervous system. An example of this is reading a book in the back seat of a moving car. The inner ears and skin receptors sense the motion, but the eyes register only the stationary pages of the book. This conflictinginformation may cause the usual motion sickness symptoms of dizziness,nausea, and vomiting.

While all five of the body's sensory organs contribute to motion sickness, excess stimulation to the vestibular system within the inner ear (the body's "balance center") is the primary reason for this condition. Balance problems ordizziness are caused by a conflict between what is seen and how the inner ear perceives it, leading to confusion in the brain. This confusion may resultin higher heart rates, rapid breathing, nausea and sweating, dizziness, and vomiting.

Pure optokinetic motion sickness is caused solely by visual stimuli, or whatis seen. The optokinetic system is the reflex that allow the eyes to move when an object moves. Many people suffer when what they view is rotating or swaying, even if they are standing still.

Additional factors that may contribute to the occurrence of motion sickness include: poor ventilation; anxiety or fear; a full stomach; alcohol; and a genetic predisposition to motion sickness.

Often viewed as a minor annoyance, some travelers are temporarily immobilizedby motion sickness, and a few continue to feel its effects for hours and even days after a trip. Most cases of motion sickness are mild and self-treatable disorders. Severe cases of motion sickness symptoms, and those that becomeprogressively worse, may require the attention of a doctor with specialized skills in diseases of the ear, nose, throat, equilibrium, and neurological system.

Medications that help ease the symptoms of motion sickness are available without a prescription (over-the-counter or OTC medicine). Alcohol should be avoided when taking any drug for motion sickness. Large doses of drugs for motionsickness may also cause dry mouth and occasional blurred vision. People withemphysema, chronic bronchitis, glaucoma, or difficulty urinating due to an enlarged prostate should not use OTC drugs for motion sickness unless directedto by their doctor.

Longer trips may require a prescription medication called scopolamine (Transderm Scop). Formerly used in the transdermal skin patch (now discontinued), itis now available in the form of a prescription gel. The gel is most effective when smeared on the arm or neck and covered with a bandage.

Alternative treatments for motion sickness have become widely accepted. Ginger (Zingiber officinale) in various forms is often used to calm the stomach. It is now known that the oils ginger contains to relax the intestinal tract and mildly depress the central nervous system. Some of the most effective forms of ginger include the powdered, encapsulated form; ginger tea prepared from sliced ginger root; or candied pieces. All forms of ginger should be taken on an empty stomach.

Placing manual pressure on the acupuncture point located about three finger-widths above the wrist on the inner arm, either by acupuncture, acupressure, or a mild, electrical pulse, has been shown to be effective against the symptoms of motion sickness. Elastic wristbands sold at most drugstores are also used to put pressure on this area.

Motion sickness is easier to prevent than to eliminate once it has begun. Thefollowing steps may help prevent the unpleasant symptoms of motion sickness:

  • Avoid reading while traveling, and do not sit in a backward facing seat.
  • Always ride where the eyes may see the same motion that the bodyand inner ears feel. Safe positions include the front seat of the car whilelooking at distant scenery; the deck of a ship where the horizon can be seen;and sitting by the window of an airplane. The least motion on an airplane isin a seat over the wings.
  • Maintain a fairly straight-ahead view.
  • Eat a light meal before traveling, or if already nauseated, avoid food altogether.
  • Take motion sickness medicine at least 30-60 minutes before travel begins.

While there is no cure for motion sickness, its symptoms can be controlled oreven prevented. Most people respond successfully to treatment, or avoid theunpleasant symptoms through prevention methods.

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