CO 2 supplementation dissociates cerebral oxygenation and middle cerebral artery blood velocity during maximal cycling.

Autor: Hansen RK; Sport Sciences, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark., Nielsen PS; Sport Sciences, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark., Schelske MW; Sport Sciences, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark., Secher NH; Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark., Volianitis S; Sport Sciences, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.; Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
Jazyk: angličtina
Zdroj: Scandinavian journal of medicine & science in sports [Scand J Med Sci Sports] 2020 Mar; Vol. 30 (3), pp. 399-407. Date of Electronic Publication: 2019 Nov 17.
DOI: 10.1111/sms.13582
Abstrakt: This study evaluated whether the reduction of prefrontal cortex oxygenation (ScO 2 ) during maximal exercise depends on the hyperventilation-induced hypocapnic attenuation of middle cerebral artery blood velocity (MCA V mean ). Twelve endurance-trained males (age: 25 ± 3 years, height: 183 ± 8 cm, weight: 75 ± 9 kg; mean ± SD) performed in three separate laboratory visits, a maximal oxygen uptake (VO 2 max) test, an isocapnic (end-tidal CO 2 tension (PetCO 2 ) clamped at 40 ± 1 mmHg), and an ambient air controlled-pace constant load high-intensity ergometer cycling to exhaustion, while MCA V mean (transcranial Doppler ultrasound) and ScO 2 (near-infrared spectroscopy) were determined. Duration of exercise (12 min 25 s ± 1 min 18 s) was matched by performing the isocapnic trial first. Pulmonary VO 2 was 90 ± 6% versus 93 ± 5% of the maximal value (P = .012) and PetCO 2 40 ± 1 versus 34 ± 4 mmHg (P < .05) during the isocapnic and control trials, respectively. During the isocapnic trial MCA V mean increased by 16 ± 13% until clamping was applied and continued to increase (by 14 ± 28%; P = .017) until the end of exercise, while there was no significant change during the control trial (P = .071). In contrast, ScO 2 decreased similarly in both trials (-3.2 ± 5.1% and -4.1 ± 9.6%; P < .001, isocapnic and control, respectively) at exhaustion. The reduction in prefrontal cortex oxygenation during maximal exercise does not depend solely on lowered cerebral blood flow as indicated by middle cerebral blood velocity.
(© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
Externí odkaz: