Decreased reaction time variability is associated with greater cardiovascular responses to acute stress

Abstract

Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75-min recovery. RT measures were generated from an ex-Gaussian distribution that yielded three predictors: mu-RT, sigma-RT, and tau-RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = -.009, SE = .005, p = .09) and diastolic (B = -.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = -.007, SE = .003, p = .03) and impaired vagal tone (B = -.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses.

Keywords: Acute stress; Cardiovascular; Reaction times; Reactivity and recovery.

Figure 1

Graphic overview of study procedure.

Figure 2

a: Scatter plot of the association between tau‐RT and systolic BP reactivity to acute mental stress (n = 262). b: Scatter plot of the association between tau‐RT and diastolic BP reactivity to acute mental stress (n = 262). Reaction time tau is expressed in milliseconds and represents the intraindividual variability in reaction times. Change in systolic and diastolic BP is the difference between baseline and acute stress values so that greater scores reflect higher stress‐induced reactivity. Individuals with lower intraindividual variability in reaction time tended to show marginally greater systolic BP (p = .09) and diastolic BP (p = .08) stress reactivity. The association is fully adjusted for age, sex, BMI, employment grade (SES), stress task perceived difficulty and involvement, correct Stroop RT trials (cognitive ability), and baseline BP.

Figure 3

a: Scatter plot of the association between tau‐RT and systolic BP stress recovery at 20 min after acute stress (n = 262). b: Scatter plot of the association between tau‐RT and systolic BP stress recovery at 75 min after acute stress (n = 262). c: Scatter plot of the association between tau‐RT and heart rate variability stress recovery at 45 min after acute stress (n = 262). Reaction time tau is expressed in milliseconds and represents the intraindividual variability in reaction times. Change in SBP is the difference between the stress recovery time point and the baseline value so that greater scores indicate impaired recovery (delayed return toward baseline) from acute stress. Change in heart rate variability is the difference between the baseline and the 45‐min poststress value so that lower values reflect impaired recovery from acute stress. Individuals with lower intraindividual variability in reaction times showed impaired vascular and vagal recovery from acute stress. These associations are fully adjusted for age, sex, BMI, employment grade (SES), stress task perceived difficulty and involvement, correct Stroop RT trials (cognitive ability), and baseline BP and HRV.