['Prospective studies of the role of psychological stress in ulcerative colitis are inconsistent or show a modest relationship. We tested the hypothesis that individual differences in autonomic function are associated with differences in the disease course of ulcerative colitis.', 'The spectral power of heart rate variability, an indirect marker of autonomic function, was measured during a standardized stress protocol in 93 ulcerative colitis patients. Patients were categorized as typical or atypical by an increase or decrease, respectively, in the high frequency band of heart rate variability from a period of acute stress to recovery 5 min later. Disease activity was measured at baseline (time 1) and a second time point (time 2) 7-37 months later.', 'An atypical pattern of heart rate variability at time 1, present in 29% of patients, was associated with lower mean disease activity at time 2 (atypical, 0.56+/-0.93; typical, 2.27+/-2.56, P=0.001). The contribution of heart rate variability pattern to explaining time 2 disease activity was independent of the contributions of other factors that differed between groups, including time 1 disease activity and lifetime corticosteroid use.'] Does autonomic response to standardized stress predict subsequent disease activity in ulcerative colitis?