The acute effect of exercise intensity on peripheral and cerebral vascular function in healthy adults

Figures

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  Figure 1.. Experimental conditions. The numbers refer to cycling intervals at a percentage of maximal oxygen uptake for each individual. The average intensity of each exercise trial was designed to be 60% maximal oxygen uptake, and all exercise trials were 30 min in duration. CON, resting control trial; HIIE, high-intensity interval exercise; MIE, moderate-intensity exercise.

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  Figure 2.. Mean ± 95% CI (shaded) middle cerebral artery blood velocity (MCAv) across the four experimental trials [control (A), moderate-intensity exercise (B), high-intensity interval exercise 1 (C), high-intensity interval exercise 2 (D)]. The shading shows the pattern of the exercise stimulus. n = 9 (5 female) due to signal loss in 1 participant. Analysis of between trial differences are presented in Table 2. CI, confidence interval.

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  Figure 3.. Peripheral vascular outcomes [baseline diameter (A), absolute change in brachial artery diameter (B), allometrically adjusted FMD (C), area under the shear rate curve until time of peak dilation (D)] before (pre) and 1 and 3 h after the four experimental trials (n = 10, 6 female). A repeated-measures ANOVA revealed a significant time by trial interaction effect for the change in brachial artery diameter after occlusion (P = 0.025; B) and the allometrically adjusted flow-mediated dilation statistic (P = 0.014; C). Only the within-trial significant differences are denoted. *Different from pre within the high-intensity interval trial 1. #Significantly different from pre within the high-intensity interval trial 2. CON, control; FMD, flow-mediated dilation allometrically adjusted to baseline diameter; HIIE, high-intensity interval exercise; MIE, moderate-intensity exercise; SRAUC, area under the shear rate curve until time of peak dilation.

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  Figure 4.. Physiological responses to 5 min of 5% carbon dioxide inhalation (n = 10, 6 female). A: MCAv change reflects the difference between resting baseline and the highest 30 s rolling average during the hypercapnic stimulus. B: the PETCO2 change is calculated as the difference between baseline and this time point. C: cerebrovascular reactivity A repeated-measures ANOVA revealed no significant time by trial interaction for any of these outcomes (P > 0.605, η2 < 0.078). CON, control; CVR, cerebrovascular reactivity; HIIE, high-intensity interval exercise; MCAv, middle cerebral artery blood velocity; MIE, moderate-intensity exercise; PETCO2, end tidal partial pressure of carbon dioxide.

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  Figure 5.. Physiological responses to 1 min of deep hyperventilation (n = 10, 6 female). The change in MCAv (A) and PETCO2 (B) reflects the difference between resting baseline and the final 10 s of the hyperventilation stimulus, used to calculate cerebrovascular reactivity (C). A repeated-measures ANOVA revealed no significant time by trial interaction for any of these outcomes (P > 0.594, η2 < 0.079). CON, control; CVR, cerebrovascular reactivity; HIIE, high-intensity interval exercise; MCAv, middle cerebral artery blood velocity; MIE, moderate-intensity exercise; PETCO2, end tidal partial pressure of carbon dioxide.