Any lay person can recognise a common faint. Doctors find the diagnosis more difficult and complicate matters further by describing the condition as vasovagal or vasodepressor syncope. To be fair, doctors see more of the people whose faints are atypical and therefore tend to feel uneasy when someone loses consciousness in a public place. Hospital doctors' disquiet is compounded nowadays by the lack of a reliable and reproducible diagnostic test. When people who faint present to hospital, therefore, they tend to be subjected to expensive investigation. Every decade or so there is a reminder that such tests are unnecessary.^1,2

Most people who faint do not consult a doctor. Hence the prevalence of fainting is difficult to gauge; nearly a quarter of an elderly population admitted to having fainted once in the previous 10 years.3 Patients with syncope (not quite the same thing as fainting) can account for 3% of all emergency visits to hospital, and one third of them …