5.4: Effect of Acute Resistance Exercise on Arterial Hemodynamics and Cerebral Blood Flow Dynamics: Does Sex Matter?

Alexander Rosenberg; Tommy Wee; Elizabeth Schroeder; Kanokwan Bunsawat; Georgios Grigoriadis; Garett Griffith; Bo Fernhall; Tracy Baynard

doi:10.1016/j.artres.2017.10.050

High-intensity resistance exercise (RE) acutely increases arterial stiffness and blood pressure (BP), coupled with reduced cerebral blood flow velocity (CBFv) and greater flow pulsatility in the cerebral circulation, which may be detrimental to cerebral microvasculature. Because females have different CV control mechanisms, it is important to assess potential sex differences in cerebrovascular responses to acute RE. Purpose To examine the effect of sex on hemodynamics and cerebral vasculature following acute RE. Methods Men (n = 18, 27 yrs, BMI = 24.2) and women (n = 14, 25 yrs, BMI = 23.8) performed RE (3 × 10, isokinetic knee flexion/extension). Measurements were obtained at baseline and post-exercise (1, 5, 30-minute). Beat-to-beat heart rate (HR), brachial BP, cardiac output (CO), stroke volume and end-tidal CO 2 were collected. CBFv was measured by transcranial Doppler, carotid BP by applanation tonometry and central pulse wave velocity (PWV) by an automated ambulatory BP monitor. Results Table 1 . CBFv pulsatility increased following RE at 1-minute post (p < 0.05) in men and was elevated above baseline 5-minute post-exercise (p < 0.05) in both groups ( Figure 1 ). Mean CBFv increased 1-min post-exercise and decreased below baseline 5-minute post-exercise (p < 0.05) in both sexes. PWV increased 1-minute post-exercise (p < 0.05) in both groups. Table 1 All Data are mean ± SD; *Exercise effect, p < 0.05. †Group effect. p < 0.05. ‡Interaction effect. p < 0.05. a Significantly different from 1-minute, b Significantly different from 5-minute. c Significantly different from 30-minute. p < 0.05). Brachial systolic BP (bSBP), brachial diastolic BP (bDBP), brachial mean BP (bMAP), Carotid systolic BP (cSBP),carotid diastolic BP (cDBP), cardiac output (CO), stroke volume (SV) and central pulse wave velocity (PWV), cerebral blood flow velocity (CBFv). Variables Baseline 1-minute 5-minute 30-minute Heart Rate(bpm)*† Men 63 ± 9 82 ± 9 71 ± 10 70 ± 8 Women 70 ± 7 93 ± 13 79 ± 10 76 ± 9 CO (L/min) * Men 4.9 ± 0.7 7.9 ± 1.3 6.1 ± 1.3 5.2 ± 0.9 Women 5.4 ±1.0 8.2 ± 1.4 6.3 ± 1.0 5.7± 0.8 SV (ml/min)*‡ Men 77 ± 16 ab 95 ± 17 bc 85 ± 17 c 72 ± 13 Women 80 ± 1 7 a 91 ± 20 bc 81 ± 14 76 ± 16 bSBP (mmHg)* Men 124 ± 10 140 ± 12 127 ± 10 127 ± 9 Women 124 ± 9 136 ± 15 122 ± 13 123 ± 9 bDBP (mmHg)* Men 72 ± 8 74 ± 7 72 ± 7 76 ± 6 Women 73 ± 5 76 ± 9 71 ± 7 73 ± 5 bMAP (mmHg)* Men 92 ± 8 100 ± 8 93 ± 8 96 ± 7 Women 95 ± 6 101 ± 11 93 ± 8 95 ± 6 cSBP (mmHg)* Men 120 ± 12 129 ± 18 125 ± 13 126 ± 10 Women 1 22 ± 12 124 ± 13 119 ± 18 123 ± 8 cDBP (mmHg)* Men 75 ± 7 74 ± 7 75 ± 7 79 ± 6 Women 74 ± 6 73 ± 6 75 ± 7 74 ± 5 cMAP (mniHg)* Men 93 ± 8 94 ± 8 94 ± 7 97 ± 7 Women 94 ± 6 93 ± 8 95 ± 9 96 ± 5 PWV (m/s)* Men 5.2 ± 0.5 5.6 ± 0.5 5.4 ± 0.5 5.2 ± 0.3 Women 5.0 ± 0.4 5.3 ± 0.5 5.1 ± 0.3 5.0 ± 0.3 CBFv Mean (cm/s)*† Men 55.8 ± 7.6 63.9 ± 9.6 51.4 ± 6.9 53.7 ± 7.9 Women 69.8 ± 14.4 81.0 ± 23.1 63.7 ± 12.9 65.8 ± 12.0 CBFv Pulsatility Index*†‡ Men 0.91 ± 0.12 ab 1.10 ± 0.16* 1.13 ± 0.17 c 0.89 ± 0.13 Women 0.81 ± 0.09 b 0.90 ± 0.18 0.95 ± 0.13 c 0.81 ± 0.11 End-Tidal CO 2 (%)* Men 4.86 ± 0.48 5.72 ± 0.66 4.64 ± 0.51 4.51 ± 0.58 Women 4.41 ± 0.60 5.44 ± 0.65 4.26 ± 0.39 4.24 ± 0.50 Figure 1 All Data are mean ± SD, *Exercise effect, p < 0.05. †Group effect, p < 0.05. ‡Interaction effect, p < 0.05. a Significantly different from 1-minute, b Significantly different from 5-minute. c Significantly different from 30-minute, p < 0.05). Conclusion Men increased CBFv pulsatility at 1-minute post-RE compared to women, demonstrating a sex difference in cerebral vascular reactivity. RE increased central arterial stiffness, mean CBFv, HR, and BP similarly for both sexes. CO was also elevated at 5-minute, but CBFv dropped below baseline and pulsatility continued to rise above baseline. This temporary disruption in cerebral autoregulation may impact brain health in both sexes.

5.4: Effect of Acute Resistance Exercise on Arterial Hemodynamics and Cerebral Blood Flow Dynamics: Does Sex Matter?

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