Ambulatory blood pressure monitoring (ABPM) is the gold standard for blood pressure (BP) assessment. In older adults, ambulatory pulse pressure (PP), mean pressure (MP), and BP dipping have been associated with altered cerebrovascular blood flow, increased cerebrovascular disease, and cognitive decline. Moderate-to-vigorous physical activity (MVPA) has favorable effects on BP and reduces cognitive decline in older adults. As hypertension rates increase in young adults, cerebrovascular pulsatility may damage white matter and accelerate cerebral aging; MVPA may combat these effects. PURPOSE: Determine if ABPM is associated with middle cerebral artery (MCA) pulsatility and cognitive performance in a group of young adults. METHODS: 68 adults (21±4 yrs; 26.6±8.0% fat; n = 53 women) underwent ABPM every 20 min between 0700 - 2200 hr and every 30 min from 2200 - 0700 hr. Transcranial Doppler measured MCA pulsatility at rest and during 3 min of cognitive stress (Stroop). MVPA was assessed over 9 days via accelerometry. Pearson correlations were run for PP, PP variability, MP, BP dipping, BP variability ratio (BPVR = standard deviation of systolic/standard deviation of diastolic pressure), and the ambulatory arterial stiffness index (AASI = 1 - regression slope of systolic and diastolic BP) with MCA pulsatility and cognitive performance (accuracy) controlling for MVPA. RESULTS: Nighttime systolic dipping was inversely associated (r = -0.25, p = 0.049) and there was a trend for diastolic dipping to be inversely associated with resting pulsatility (r = -0.23, p = 0.06). No other ABPM measures were related with resting MCA pulsatility. MCA pulsatility during cognitive stress was associated with daytime systolic pressure (r = 0.38, p < 0.01), average daily PP (r = 0.33, p = 0.01), and systolic and diastolic dipping (r = -0.34, p = 0.01 and r = -0.25, p = 0.04, respectively). Accuracy during the cognitive stress task was not associated with any ABPM measure (p ≥ 0.09). CONCLUSION: These data suggest that nighttime BP dipping may be related to reduced cerebrovascular pulsatility at rest and during cognitive stress. Additionally, greater daytime systolic BP and PP may be associated with increased MCA pulsatility during cognitive stress. ABPM is associated with cerebral pulsatility but not cognitive performance in young adults.