Some people feel queasy while travelling in a car, bus, ship or plane. But imagine struggling to suppress uncontrollable nausea while skiing.
And if it's got nothing to do with a blinding hangover from the previous night's excess, chances are, you're suffering from "ski sickness".
An expert from Bern University Hospital has been credited with discovering a form of motion sickness that affects many downhill skiers.
Rudolf Häusler, professor at the university's ear, nose and throat department, says victims suffer the same symptoms as with car or seasickness.
"Many people can develop ski sickness by skiing, but people who are sensitive to motion sickness in general are especially prone, " Häusler said.
"It appears on so-called white days, when the visibility is less good, [and] when you don't see the surroundings or contours. This gives contradictory information [to the brain].
Häusler first came across the phenomenon when patients came to him complaining of dizziness, lightheadedness and even nausea experienced while skiing.
He soon discovered that his charges had not fallen foul of Switzerland's white wines, but were serious. One day, while standing still on steep slope in foggy conditions, he suddenly got a sensation of movement.
As the professor shifted his body weight to initiate a turn, he crashed to the ground, still on his original spot. Häusler then got a sickening feeling in his stomach.
The incident awoke his interest and prompted him to study in detail patients who reported the symptoms. In his study, he focused on 11 people, and now guesses that around 10 percent of skiers suffer the illness at some stage.
"At first I thought it was quite rare, " Häusler said. "But in the mean time every time I spoke in auditoriums and so on about ski sickness it actually appeared that many people have experience such symptoms.
"Sometimes they were not aware. They thought for instance that they had not eaten something well at noon, or had taken alcohol, and for this reason they were vomiting. But actually, it was ski- sickness."
Häusler says the causes of ski-sickness are related to the inner-ear organs used to balance the body for skiing. Those organs are linked to eyesight and other senses.
An episode may be even be triggered by the rigidity of ski boots, which deprive the brain important sensory feedback from a skier's foot. Add in low-light conditions, perhaps a fear of heights or ski accident, and even a liquid lunch, and the chance of ski sickness increases.
So is there a cure? Häusler says the quickest answer is to take off your skis. Or for those still wanting to ski, relief can be found through standard travel-sickness medication.
by Jacob Greber and Samantha Tonkin