Exercise intensity and middle cerebral artery dynamics in humans

• Published in: Respiratory physiology & neurobiology 2019-04, Vol.262, p.32-39
• Main Authors: Witte, Emily, Liu, Yumei, Ward, Jaimie L., Kempf, Katie S., Whitaker, Alicen, Vidoni, Eric D., Craig, Jesse C., Poole, David C., Billinger, Sandra A.
• Format: Article
• Language: English
• Subjects: Acute exercise; Adult; Aerobic fitness; Aged; Aged, 80 and over; Aging; Aging - physiology; Blood Flow Velocity; Blood pressure; Blood Pressure - physiology; Cardiorespiratory Fitness - physiology; Cerebral blood flow velocity; Exercise - physiology; Female; Heart Rate - physiology; Humans; Male; Middle Aged; Middle cerebral artery; Middle Cerebral Artery - diagnostic imaging; Middle Cerebral Artery - physiology; Ultrasonography, Doppler, Transcranial; Young Adult
• ISSN: 1569-9048; 1878-1519; 1878-1519
• DOI: 10.1016/j.resp.2019.01.013

•Stimulus-response profiles during exercise are important for understanding control processes.•Middle cerebral artery blood flow velocity increased systematically with work rate.•Amplitude response associated with age and estimated fitness.•Maintaining fitness may benefit cerebrovascular response across aging. Despite its necessity for understanding healthy brain aging, the influence of exercise intensity on cerebrovascular kinetics is currently unknown. We, therefore characterized middle cerebral artery blood flow velocity (MCAv) kinetics associated with two exercise intensities: low and moderate. We hypothesized that increasing exercise intensity would increase the MCAv amplitude response (Amp) and that age and estimated fitness (V̇O2max) would be related to Amp. Baseline (BL) values were collected for 90-seconds followed by a 6-minute exercise bout. Heart rate, end-tidal CO2, mean arterial pressure and MCAv were recorded throughout. MCAv kinetics were described by Amp, time delay (TD) and time constant (τ). Sixty-four adults completed the study. Amp was greater during moderate compared to low exercise intensity (p