The effect of cardiac cycle phase on reaction time among individuals at varying risk for hypertension

Existing evidence suggests that baroreceptor stimulation may impair sensorimotor functioning. The purpose of this study was to determine whether the adverse effect of baroreceptor stimulation on sensorimotor functioning is more pronounced among individuals at increased risk for hypertension. A visual reaction time task was completed by 93 normotensive men and women at varying risk for hypertension, as defined by the combination of their resting systolic blood pressure and their parental history of hypertension. To correspond with natural fluctuations in baroreceptor stimulation across the cardiac cycle, stimuli were administered at one of 12 intervals after the occurrence of an electrocardiogram (ECG) R-wave (R + 50, 100, 150... 600 ms). Reaction time to stimuli presented during the middle of the cardiac cycle, when baroreceptor stimulation is increased, was significantly slower than to stimuli presented earlier in the cycle, when baroreceptor stimulation is reduced. The influence of cardiac cycle phase on reaction time was similar among participants with high-normal, normal, or low-normal systolic blood pressure as well as among participants with a positive or negative parental history of hypertension. These findings suggest that baroreceptor stimulation impairs sensorimotor functioning in normotensive men and women; however, this effect is not more pronounced among individuals at increased risk for hypertension.