When you are feeling nauseous, why does a cold environment make you feel so much better? Contrast this to a warmer, more humid environment, which makes you feel much, much worse.
There seems to be no clear explanation for this effect, but lots of possible ideas 鈥� Ed
鈥� As any real sufferer from motion sickness can assure you, the effect of coolness is marginal. They can still get very, very sick in the teeth of the most refreshing gales.
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The main contributor to motion sickness is conflict between visual signals and signals from the semicircular canals located in the ear and associated with balance. Below decks on a ship, assorted stresses aggravate the effects, especially lying claustrophobically in a stuffy cabin, being unable to fix your gaze on stable points of reference, and your head swinging passively at the whim of a pitching bunk. Smells of diesel and vomit, engine rumblings and non-sufferers wittering on about nauseating anti-nausea remedies do not help.
Erect on deck, with clean air, an unobstructed view of the horizon and comparative peace, the most noxious sensory triggers and emotional factors disappear. In particular, avoid leaning against stanchions and use the horizon as a stable reference for orientation. You can then ignore the caprices of the rolling vessel, adapt to the motion and develop sea legs.
When defying the elements and feeling under control in this way is effective, it is no wonder one associates coolness and fresh breezes with freedom from claustrophobically nauseating stimuli. Staring through rolling portholes or hanging over a chaotically heaving taffrail, while gazing down at chaotically heaving water, doesn鈥檛 work at all, breeze or no breeze.
Jon Richfield, Somerset West, South Africa
鈥� One reason that people who are nauseous feel worse if they move from a cold to a hot environment may be that exposure to heat induces greater expression of the enzyme haem oxygenase. This is a heat-shock protein that is produced throughout the human body. It breaks down haemoglobin, myoglobin and cytochromes into iron, biliverdin and carbon monoxide, and increases this process in response to stressors of any kind.
In hot environments, the concentration of carbon monoxide in exhaled breath may be 20 times higher than when in cold environments. Such high levels of endogenous carbon monoxide may cause not just nausea but also other symptoms of heat stress including vomiting, headache, fatigue and weakness.
Albert Donnay, Lutherville, Maryland, US
鈥� Once, while working up a ladder, I managed to bring about an undesired impact between the hammer I was holding in one hand and the thumb of the other. A friend of mine, who has experience in such matters, informed me that there was a simple remedy and promptly stamped on my toe. He was quite right; the thumb gave me no further trouble. His toe-stamp remedy is obviously related to this freezing-your-body cure.
鈥淚 once managed to bring about an impact between my hammer and thumb. My friend remedied it by stamping on my toe鈥�
Mark Wallace, Beetsterzwaag, Netherlands
鈥� I wonder whether this is the wrong question. The right one might be 鈥淲hy do you feel better when you get to a climate you like?鈥�
I once had a nasty and extended episode of tourist鈥檚 tummy in Mexico in July 1965, developed at a high, cool, dry observatory site. It was beginning to seem as if the nausea would last forever. But then I got off a plane and stepped into the very warm, very moist air of Acapulco and was immediately cured (and also very hungry).
I鈥檓 sure that you will get lots of different answers to the question, illustrating a theorem first proposed by which states that a theorist can explain any correlation, and its inverse.
Virginia Trimble, Irvine, California, US