Objective: Prospective studies have demonstrated that anxiety predicts
sudden cardiac death, but the mechanism underlying this increased ris
k is unclear. This study examined whether anxiety is associated with r
eductions in vagal control of heart rate in healthy volunteers. Method
: Trait anxiety (T-ANX) was measured, using the Spielbeger State-Trait
Anxiety Inventory (STAI), in 93 healthy men and women 25 to 44 years
of age. Power spectral analysis was used to measure two indices of vag
al control: baroreflex control of heart rate (BRC) and respiratory sin
us arrhythmia (RSA). Results: High trait anxiety (T-ANX > 41, N = 23)
was associated with significantly reduced vagal control of the heart,
compared with low trait anxiety (T-ANC < 31, N = 22), as indicated by
a 36% reduction in BRC (p < .001) and an 8% reduction in RSA (p < .05)
. Furthermore, T-ANX scores were negatively correlated with levels of
BRC (r = -.30, p < .005), and levels of RSA (r = -.26, p < .05). Concl
usions: These findings provide evidence that trait anxiety is associat
ed with reductions in vagal control of the heart. Additional studies a
re needed to examine whether low vagal control is involved in the incr
eased risk of sudden cardiac death associated with anxiety.