Autonomic response to stress in interstitial cystitis

Previous studies have documented elevations in indices of sympathetic activity in cats and humans with interstitial cystitis (IC). To examine potential autonomic dysregulation in IC we examined the effects of a laboratory mental stress challenge on blood pressure and heart rate (HR) in patients with IC and healthy controls.

A total of 14 female patients with IC and 14 age matched controls participated in a laboratory session, including a 25-minute mental stress challenge. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR were measured at intervals before, during and following the stressor. The level of chronic stress, symptom severity and pain at voiding were assessed.

Mean age was 49 years (range 32 to 66). The resting HR of patients with IC (82.02 bpm) was significantly higher than that of controls (63.31 bpm, p = 0.0001). There was also suggested evidence of elevated resting DBP in patients with IC (p = 0.07) but no significant difference in mean resting SBP. Autonomic arousal elicited by the laboratory stressor did not differ between the groups and subjects in each group perceived the task as equally stressful. Patients with IC had significantly elevated HR at each time point compared with controls (p <0.0001) with an average mean difference +/- SD between the groups of 19.5 +/- 4.0 (main effect for group p <0.0001). Although consistent increases in SBP and DBP were observed in patients after baseline, these differences were not significant.

Patients with IC had an increased HR at baseline and throughout a laboratory mental stress challenge compared to healthy age matched women. No differences in HR or blood pressure reactivity were observed between the 2 groups.