The experience of psychosomatic symptoms in the hyperventilation provocation test and in non-hyperventilation tasks

End-tidal CO₂ was monitored in 16 nonpatient subjects during the performance of a continuous perceptual-motor task, once with and once without threat of aversive shock (counter-balanced), and during performance of the hyperventilation (HV) provocation test. Respiratory alkalosis (below 2.5% end-tidal CO₂) was produced by HV but not by the other treatments. Reports of task-related psychosomatic complaints were frequent with HV, but were also reported to some extent with the other treatments. It is concluded that psychosomatic complaints, often assumed to be associated with HV, were not specifically related to degree of hypocapnia. The constellation of seriousmindedness, perceived threat and negative hedonic tone appeared to interact with the drop in end-tidal CO₂. Our findings suggest a multifactorial model for understanding the experience of psychosomatic complaints.