Susceptibility to seasickness.

This paper explains part of the observed variability in passenger illness ratings aboard ships by gender, age and sickness history. Within the framework of a European project, 2840 questionnaires, gathered on several ships operating all over Europe, were analysed. Gender, age and sickness history all had a highly significant effect on seasickness. Furthermore, these effects could be characterized by two fixed parameters describing a general age effect, a third parameter dependent on sickness history and a fourth parameter dependent on gender. Female illness ratings peaked at an age of 11 years, 1.5 times as high as male ratings, which peaked at an age of 21 years. At higher ages, illness ratings decrease to only 20% of their maximum, reducing gender differences to zero. Passengers with a previous history of seasickness rated their illness about two times higher than those who had not felt sick before.