There are several reasons why 'rich' people (i.e., "society women") fainted in past times, though most movies and novels tend to use only one:
- intentionally fainting, for effect. The node on swooning lessons gives an excellent background on this. This is mostly what you'll see in literature and film. However, swooning as a social skill was no doubt inspired by the all-too-common incident of...
- unintentionally fainting, for health reasons. This was commonly due to a combination of one or more things:
- anemia, caused by lack of iron in the diet, particularly for women of childbearing age who remained ignorant about the demands of menstruation. This makes the blood "thinner", and less able to carry oxygen. ("Delicate" women would often not eat meat, which was considered "masculine" and too rough for gentle stomachs.)
- sedentary lifestyle. This couples quite nicely with anemia, as people unused to physical activity (the "delicate" type never sported or exercised) have trouble with blood circulation when they suddenly attempt strenuous activity (which can be as simple as standing up too fast - ask your grandmother!)
- the wearing of corsets. This was probably quite common as a cause, actually. Corsets are designed to be so tight that they compress chest walls. Obviously, this poses a problem for the lungs, which can't expand fully, causing less oxygen to be exchanged for carbon dioxide in the bloodstream. The node on wearing a corset details how difficult it is to wear one relatively safely.