Mental stress and cardiovascular reactivity in humans: a time‐dependent response (852.6)

Abstract

Cardiovascular reactivity (CVR) to acute laboratory mental stress (MS) has been extensively studied as a potential predictor of future cardiovascular risk, but length of MS trial can vary across studies. We hypothesized that CVR would be different between short (1 min) versus longer (3 and 5 min) MS trials, but that within‐subject reactivity would be correlated. We recorded heart rate (HR) and beat‐to‐beat blood pressure reactivity to 1 min, 3 min and 5 min mental arithmetic in 21 subjects (age, 20±3 yrs, 10 men and 11 women). Mean arterial pressure (MAP) reactivity to 1min of MS (∆6±1 mmHg) was blunted compared to 3 min (∆11±1 mmHg; P˂.001) and 5 min (∆11±1 mmHg; P˂.001) of MS. In contrast, HR reactivity to 1 min of MS (∆21±2 beats/min) was augmented compared to 3 min (∆17±2 beats/min; p<.01) and 5 min (∆17±2 beats/min; p<.01) of MS. HR reactivity (range, r=.648 to .790; p<.001), but not MAP reactivity, was consistently correlated across MS trials. When probed for sex differences, CVR across trials tended to be more correlated in women. In conclusion, our findings demonstrate that CVR to acute MS is time‐dependent, thus caution should be taken in interpreting CVR data. However, CVR responders for shorter MS trials appear to remain responders for longer trials, especially in women.