Influence of Aerobic Fitness and Gender on Cerebrovascular Reactivity to Carbon Dioxide

Christopher Marley, Julien Brugniaux, Danielle Hodson, Philip Ainslie, Karl New, Damian Bailey

Allbwn ymchwil: Pennod mewn Llyfr/Adroddiad/Trafodion CynhadleddCyfraniad i gynhadleddadolygiad gan gymheiriaid


Background: Cerebrovascular reactivity to carbon dioxide (CVRCO2) is an established measure of cerebrovascular function, of which females record elevated values (1). We recently reported the positive relationship between CVRCO2 and maximal oxygen consumption (VO2MAX) in healthy young males (2, 3). However, it remains to be determined whether similar relationships are apparent in females. Therefore, we aimed to determine whether i) females have an elevated CVRCO2 compared to males and ii) CVRCO2 increases with VO2MAX.
Methods: Forty healthy participants (20♀/20♂) were recruited into the study and assigned to 1 of 4 groups based on their gender (♀ vs. ♂) and training status (trained, > 150 minutes aerobic exercise per week vs. untrained, < 150 minutes of aerobic exercise per week. Participants' characteristics are detailed in Table 1. CVRCO2 was assessed in response to a 3-minute exposure to hypercapnea (5% CO2). Middle cerebral artery velocity (MCAv; transcranial Doppler) and end-tidal CO2 (PETCO2; capnography) were continuously recorded throughout the procedure as described previously (4). VO2MAX was assessed via an incremental exercise test to volitional exhaustion (semi-recumbent cycle ergometer) and online expiratory gas exchange. Following confirmation of distribution of normality (Shapiro-W-Wilk t-tests), between group differences (gender vs. training status) were analysed using a 2-way ANOVA. Relationships between VO2MAX and CVRCO2 were determined using Pearson Product Moment correlations. Significance was set at P < 0.05 and data are expressed as mean + SD.
Results: By design, the trained participants of both genders had a higher VO2MAX (P < 0.05). Trained participants recorded a greater CVRCO2 than the untrained, while females recorded a greater CVRCO2 than males (P < 0.05). There were no interaction effects between variables. Figure 1 illustrates the positive correlations between VO2MAX and CVRCO2 for both genders (males, r = 0.79; females, r = 0.64; P < 0.05).
Conclusion: These findings confirm that females elicit a greater CVRCO2 than males. Moreover, we show for the first time that the cerebrovascular benefits of regular aerobic exercise are equally extended to females. These findings are particularly important given the established relationship between impaired CVRCO2 and stroke risk in later life
Iaith wreiddiolSaesneg
TeitlProceedings of The Physiological Society
Is-deitlPhysiology 2014 (London, UK)
CyhoeddwrThe Physiological Society
StatwsCyhoeddwyd - 2014

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