I get a weird motion sickness thing in cars and planes that seems to be triggered by lack of food. Finally science comes along and gives me a possible explanation, from a story in the March Sci Am about motion sickness:
Postural instability[–]the inability to maintain balance[–]was considered a symptom of motion sickness. Not so, Stoffregen says. Although postural control relies on sensory feedback, motion sickness is really a sign that the motor-control system is going haywire.
Volunteers stand in a room watching a map of the U.S. quiver back and forth by 1.8 cm. Clarifications: 1) The room itself can vibrate, too. This U. Minn. write-up makes it sounds like Tilt-A-Whirl. Here’s a pic:
2) Apparently Stoffregen – first name: Thomas; kinesiologist at U. Minn. – is saying that if motion sickness was entirely from crossed perceptual cues – linear and angular motion sensation in the ear conflicting with where eyes and muscles tell us the body is moving – then ralphing would be as common as shaking hands. But it isn’t.
From U. Minn. again:
He measures the movement of people subjected to his sickness-inducing tests, and “the people who are going to get sick commence to move in really weird ways,” he says, imitating the type of staggering walk typical after tequila night at the bar. Even when the subjects are strapped to an upright stretcher, the ones who feel sick still move a little. “They wriggle,” says Stoffregen. Due to individual differences to sensitivity, only about half of Stoffregen’s test subjects feel sick. Those who don’t also don’t wriggle, which makes Stoffregen think that movement is the key factor behind motion sickness.
Now the punch line of the Sci Am story is clearer to me:
Students standing with their feet five centimeters apart tend to get motion sickness about 60 percent of the time. Spreading their legs to 30 centimeters increases the stability of the head and torso and decreases the incidence of motion sickness to about 20 percent. Stoffregen says that by monitoring body sway, he can predict the onset of motion sickness with 60 percent accuracy.
It’s (still) like I’ve always said: when in doubt, tighten your core muscles.