Among psychobiological concepts concerning origin and persistence of a
nxiety disorders, the phenomenon of cardiovascular deconditioning (CD)
has drawn little attention. Many of the cardiovascular complaints see
n in patients with anxiety disorders can be evoked by CD. CD has been
studied in astronauts during and after space flights, can be provoked
on earth by using the 6 degrees head-down tilt (HDT) method, and occur
s after prolonged bed rest. HDT studies conducted in our laboratory wi
th healthy subjects revealed the detrimental cardiovascular effects of
this posture. Based on this observation it was hypothesized that the
CD seen in agoraphobics (with and without panic attacks) is mainly due
to the long period of time they spent in supine position. 15 agorapho
bics, 15 age-, sex- and body weight-matched snake-/spider-phobics and
15 healthy controls served as subjects. Orthostatic challenge, bicycle
ergometry, and the behavior protocols filled in during 1 week showed
that the agoraphobics are characterized by CD and spent significantly
more time per day in supine position than spider-/snake-phobics and co
ntrols. On the basis of these findings a psychophysiological model is
proposed combining the prolonged bed rest with cardiovascular dysregul
ation and the concomitant avoidance behavior.