The Influence of Sex, Fitness, BMI, and Cardiovascular Risk Factors on Cerebral Blood Velocity Responsiveness to Graded Exercise Testing in Middle-Aged Adults

Mean middle cerebral artery velocity (MCAv) and the pulsatility index (PI), at rest and in response to exercise, are important markers of cerebrovascular health status in middle-aged adults, when vascular decline assumes substantial relevance. Thus, this study aimed to describe and compare the responses of MCAv and PI to incremental exercise. Two hundred and forty-eight volunteers (50-58 years, 55% women) completed a ramp test on a cycle-ergometer. Gas exchange was assessed on a breath-by-breath basis. MCAv was measured via transcranial Doppler and PI calculated. Cardiovascular disease risk (CVR) factors were determined and comprised of measurements of central obesity, blood pressure, fasted plasma glucose, and lipids. The MCAv and PI responses to exercise were compared across body mass index categories, CVR score, and fitness status. We found sex-specific differences in MCAv and PI at rest. However, both sexes showed a similar relative change to baseline (Δ%MCAvmean). Regarding body mass index, obese women (body mass index > 30 kg m-2) had lower MCAv and Δ%MCAvmean and higher PI compared with normo-weight women during exercise. Apart, women with a 0 CVR score showed higher MCAv and lower PI during exercise than those with a score of +3 CVR. Differences between low and high CVR during exercise in Δ%MCAvmean were also found. Eventually, low fitness showed diminished MCAv and a lower response to exercise than high fitness. This study has highlighted significant variability in MCAv responsiveness to exercise among middle-aged adults. Body composition, CVR, and fitness status may play a significant role in preserving cerebrovascular health. These findings shed light on the importance of understanding the cerebrovascular response to exercise.