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. Depending on the cause it can also be referred to as seasickness, car sickness, simulation sickness, airsickness, or space sickness.


Symptom
Dizziness, fatigue, and nausea are the most common symptoms of motion sickness. Sopite syndrome is also a side effect of motion sickness. If the motion causing nausea is not resolved, the sufferer will frequently vomit. Unlike ordinary sickness, vomiting in motion sickness tends not to relieve the nausea.

Motion sickness on the sea can result from being in the berth of a rolling boat without being able to see the horizon. Sudden jerky movements tend to be worse for provoking motion sickness than slower smooth ones, because they disrupt the fluid balance more.Cars driving rapidly around winding roads or up and down a series of hills will upset more people than cars that are moving over smooth, straight roads. Looking down into one's lap to consult a map or attempting to read a book while a passenger in a car may also bring on motion sickness.

Natural
One common suggestion is to simply look out of the window of the moving vehicle and to gaze toward the horizon in the direction of travel. This helps to re-orient the inner sense of balance by providing a visual reaffirmation of motion.

In the night, or in a ship without windows, it is helpful to simply close one's eyes, or if possible, take a nap. This resolves the input conflict between the eyes and the inner ear. Napping also helps prevent psychogenic effects (i.e. the effect of sickness being magnified by thinking about it).

Fresh, cool air can also relieve motion sickness slightly, although it is likely this is related to avoiding foul odors which can worsen nausea.

Chemical
Over-the-counter and prescription medications are readily available, such as Dramamine (dimenhydrinate) and Bonine/Antivert (meclizine).

Scopolamine is effective and is sometimes used in the form of transdermal patches (1.5mg) or as a newer tablet form (0.4mg). The selection of a transdermal patch or scopolamine tablet is determined by a doctor after consideration of the patient's age, weight, and length of time treatment is required.

Interestingly, many pharmacological treatments which are effective for nausea and vomiting in some medical conditions may not be effective for motion sickness. For example, metoclopramide and prochlorperazine, although widely used for nausea, are ineffective for motion-sickness prevention and treatment. This is due to the physiology of the CNS vomiting centre and its inputs from the chemoreceptor trigger zone versus the inner ear. Sedating anti-histamine medications such as promethazine work quite well for motion sickness, although they can cause significant drowsiness.

Ginger root is commonly thought to be an effective anti-emetic. One study concluded that sucking on crystallized ginger or sipping ginger tea can help to relieve the nausea,[16] while a second study concluded it had only a placebo effect.

Ginger is reported to calm the pyloric valve located at the base of the stomach.[16] This relaxation of the valve allows the stomach to operate normally whereby the contents will enter the small intestine instead of being retained within the stomach. It is this undesirable effect of retention in the stomach that eventually results in vomiting. Vomiting is not seasickness but is only a symptom or side effect; although the effect most commonly associated with seasickness. This link reports on a ginger study; notice the comment about less vomiting when taking ginger, but not less nausea.

TIPS FOR TRAVELERS
In addition to, or instead of, using the following remedies, you can take action to minimize or stave off motion sickness.

• Before you travel, avoid salty, greasy, or spicy food, plus caffeine and nicotine.

• Don’t read or watch a video while traveling. Instead, if possible, focus on something in the distance. If you’re on an airplane, try to get a window seat so you can gaze outside of the plane. If you’re in a car or train, try to get a seat as near to the front as possible. Don’t face the rear. If you’re on a ship, go outside or to a window so you can look at the horizon.

• Keep your head as still as possible.

• Relax. Stress can worsen the symptoms.

• Get fresh, cool air. When traveling by plane, direct the overhead vent on you. Also, take along or request a cold compress to stay cool.

• If you are suffering from extreme side effects, lie down if at all possible.

Before your next trip, practice these tips, and if necessary, try one of the listed medications. You may just find the skies friendlier to fly.


References
1. http://www.mcw.edu/clinicalinformatics/healthlink.htm
2. http://www.pctoday.com/editorial/article.asp?article=articles/2006/t0405/33t05/33t05.asp&guid=