Middle cerebral artery blood flow velocity during a 4 km cycling time trial.

Ben Rattray, Brittany A Smale, Joe Northey, Disa J Smee, Nathan G. Versey

Research output: Contribution to journalArticle

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Abstract

Purpose: This study sought to describe middle cerebral artery blood flow velocity (MCAv) during a 4 km cycling time trial, and relate it to different pacing strategies adopted by participants.Methods: After familiarisation and a standardised exercise protocol, 15 male trained cyclists rode a 4 km time trial on a cycling ergometer. MCAv was assessed via transcranial Doppler ultrasound in the right hemisphere at resting baseline, and throughout the time trial. Mean arterial pressure, end-tidal partial pressure of carbon dioxide (PetCO2) and heart rate were assessed alongside MCAv. Plasma lactate was assessed post time trial. Data were compared depending upon whether participants completed the time trial with a positive (first half faster than the last) or negative pacing profile although there was no difference in the time to completion with either pacing strategy (positive 344 ± 23 s, negative 334 ± 14 s; p = 0.394).Results: Lower mean MCAv (positive pacing -7.6 ± 14.2%, negative pacing +21.2 ± 15.0% compared to resting baseline measures; p = 0.004) and lower PetCO2 (significant interaction p < 0.001) towards the end of the time trial were observed with positive compared to negative pacing. Heart rate and lactate did not differ between pacing strategies.Conclusions: Changes in MCAv appear to depend on the pacing strategy adopted, with a positive pacing strategy likely to contribute to a hyperventilatory drop in PetCO2 and subsequent reduction in MCAv. Although lower cerebral blood flow cannot be directly linked to an inability to raise or maintain power output during the closing stages of the time trial, this potential contributor to fatigue is worth further investigation.
Original languageEnglish
Pages (from-to)1241-1248
Number of pages8
JournalEuropean Journal of Applied Physiology
Volume117
Issue number6
DOIs
Publication statusPublished - 1 Jun 2017

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Cerebrovascular Circulation
Blood Flow Velocity
Middle Cerebral Artery
Lactic Acid
Heart Rate
Doppler Ultrasonography
Partial Pressure
Carbon Dioxide
Fatigue
Arterial Pressure

Cite this

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title = "Middle cerebral artery blood flow velocity during a 4 km cycling time trial.",
abstract = "Purpose: This study sought to describe middle cerebral artery blood flow velocity (MCAv) during a 4 km cycling time trial, and relate it to different pacing strategies adopted by participants.Methods: After familiarisation and a standardised exercise protocol, 15 male trained cyclists rode a 4 km time trial on a cycling ergometer. MCAv was assessed via transcranial Doppler ultrasound in the right hemisphere at resting baseline, and throughout the time trial. Mean arterial pressure, end-tidal partial pressure of carbon dioxide (PetCO2) and heart rate were assessed alongside MCAv. Plasma lactate was assessed post time trial. Data were compared depending upon whether participants completed the time trial with a positive (first half faster than the last) or negative pacing profile although there was no difference in the time to completion with either pacing strategy (positive 344 ± 23 s, negative 334 ± 14 s; p = 0.394).Results: Lower mean MCAv (positive pacing -7.6 ± 14.2{\%}, negative pacing +21.2 ± 15.0{\%} compared to resting baseline measures; p = 0.004) and lower PetCO2 (significant interaction p < 0.001) towards the end of the time trial were observed with positive compared to negative pacing. Heart rate and lactate did not differ between pacing strategies.Conclusions: Changes in MCAv appear to depend on the pacing strategy adopted, with a positive pacing strategy likely to contribute to a hyperventilatory drop in PetCO2 and subsequent reduction in MCAv. Although lower cerebral blood flow cannot be directly linked to an inability to raise or maintain power output during the closing stages of the time trial, this potential contributor to fatigue is worth further investigation.",
keywords = "Brain, Exercise, Pacing, Performance",
author = "Ben Rattray and Smale, {Brittany A} and Joe Northey and Smee, {Disa J} and Versey, {Nathan G.}",
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Middle cerebral artery blood flow velocity during a 4 km cycling time trial. / Rattray, Ben; Smale, Brittany A; Northey, Joe; Smee, Disa J; Versey, Nathan G.

In: European Journal of Applied Physiology, Vol. 117, No. 6, 01.06.2017, p. 1241-1248.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Middle cerebral artery blood flow velocity during a 4 km cycling time trial.

AU - Rattray, Ben

AU - Smale, Brittany A

AU - Northey, Joe

AU - Smee, Disa J

AU - Versey, Nathan G.

PY - 2017/6/1

Y1 - 2017/6/1

N2 - Purpose: This study sought to describe middle cerebral artery blood flow velocity (MCAv) during a 4 km cycling time trial, and relate it to different pacing strategies adopted by participants.Methods: After familiarisation and a standardised exercise protocol, 15 male trained cyclists rode a 4 km time trial on a cycling ergometer. MCAv was assessed via transcranial Doppler ultrasound in the right hemisphere at resting baseline, and throughout the time trial. Mean arterial pressure, end-tidal partial pressure of carbon dioxide (PetCO2) and heart rate were assessed alongside MCAv. Plasma lactate was assessed post time trial. Data were compared depending upon whether participants completed the time trial with a positive (first half faster than the last) or negative pacing profile although there was no difference in the time to completion with either pacing strategy (positive 344 ± 23 s, negative 334 ± 14 s; p = 0.394).Results: Lower mean MCAv (positive pacing -7.6 ± 14.2%, negative pacing +21.2 ± 15.0% compared to resting baseline measures; p = 0.004) and lower PetCO2 (significant interaction p < 0.001) towards the end of the time trial were observed with positive compared to negative pacing. Heart rate and lactate did not differ between pacing strategies.Conclusions: Changes in MCAv appear to depend on the pacing strategy adopted, with a positive pacing strategy likely to contribute to a hyperventilatory drop in PetCO2 and subsequent reduction in MCAv. Although lower cerebral blood flow cannot be directly linked to an inability to raise or maintain power output during the closing stages of the time trial, this potential contributor to fatigue is worth further investigation.

AB - Purpose: This study sought to describe middle cerebral artery blood flow velocity (MCAv) during a 4 km cycling time trial, and relate it to different pacing strategies adopted by participants.Methods: After familiarisation and a standardised exercise protocol, 15 male trained cyclists rode a 4 km time trial on a cycling ergometer. MCAv was assessed via transcranial Doppler ultrasound in the right hemisphere at resting baseline, and throughout the time trial. Mean arterial pressure, end-tidal partial pressure of carbon dioxide (PetCO2) and heart rate were assessed alongside MCAv. Plasma lactate was assessed post time trial. Data were compared depending upon whether participants completed the time trial with a positive (first half faster than the last) or negative pacing profile although there was no difference in the time to completion with either pacing strategy (positive 344 ± 23 s, negative 334 ± 14 s; p = 0.394).Results: Lower mean MCAv (positive pacing -7.6 ± 14.2%, negative pacing +21.2 ± 15.0% compared to resting baseline measures; p = 0.004) and lower PetCO2 (significant interaction p < 0.001) towards the end of the time trial were observed with positive compared to negative pacing. Heart rate and lactate did not differ between pacing strategies.Conclusions: Changes in MCAv appear to depend on the pacing strategy adopted, with a positive pacing strategy likely to contribute to a hyperventilatory drop in PetCO2 and subsequent reduction in MCAv. Although lower cerebral blood flow cannot be directly linked to an inability to raise or maintain power output during the closing stages of the time trial, this potential contributor to fatigue is worth further investigation.

KW - Brain

KW - Exercise

KW - Pacing

KW - Performance

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U2 - 10.1007/s00421-017-3612-2

DO - 10.1007/s00421-017-3612-2

M3 - Article

VL - 117

SP - 1241

EP - 1248

JO - European Journal of Applied Physiology and Occupational Physiology

JF - European Journal of Applied Physiology and Occupational Physiology

SN - 1439-6319

IS - 6

ER -