Systolic Blood Pressure And Heart Rate Recovery Are Related To Cognition In Healthy Older Adults

Abstract

SYNOPSIS: Attenuated heart rate recovery (HRR) and systolic blood pressure recovery (SBPR) after a maximal exercise test (VO2peak) are linked to cardiovascular risk factors (CVRF). The relationship between the presence of CVRF and reduced cognition is well established in older adults. Yet the explicit relationship between HRR or SBPR and cognition has yet to be studied in older adults, here we found that reduced HRR and SBPR were directly related to worse cognition. PURPOSE: To determine if a relationship exists between cognition and HRR or SBPR measured during a VO2peak test in older adults METHODS: Prior to enrollment in an intervention, a total of 68 participants (70±6yrs; 45 women) completed neuropsychological tests and a VO2peak incremental test on a cycle ergometer. After standard verifications at rest, heart rate and blood pressure were continuously monitored during the incremental test and a 3-minute recovery period. HRR was calculated as the first minute recovery heart rate subtracted from the maximal heart rate during the test, where lower numbers were interpreted as reduced recovery and increased likelihood of CVRF. SBPR was defined as the maximal reading during the test divided by the first- and third-minute recovery where a higher ratio indicates higher probability of CVRF. Correlations analyses were completed with sex, age and education as covariates. RESULTS: VO2peak was inversely related to Stroop inhibition reaction time (r = -0.275, p = 0.048). HRR approached significance with total digit span score (r= 0.230; p = 0.090). SBPR was negatively associated with Stroop inhibition reaction time (r = -0.327; p = 0.042) and Stroop switching reaction time (r = -0.379; p = 0.017) CONCLUSIONS: For the first time, we identified that there is a direct relationship between SBPR and cognitive outcomes. HRR and SBPR are early indicators of cardiovascular and endothelial dysfunction, thus, it could be that the relationship between cognition and CVRF are mediated by early vascular dysfunction that could be affecting upstream cerebral vascular health. This hypothesis could be confirmed in future work including larger samples of individuals as well as neuroimaging techniques.