Título:	Sex differences in blood pressure regulation during ischemic isometric exercise : the role of the β-adrenergic receptors
Autor(es):	Samora, Milena Incognito, Anthony V. Vianna, Lauro Casqueiro
Assunto:	Pressão arterial Exercícios físicos
Data de publicação:	10-Ago-2019
Editora:	American Physiological Society
Referência:	SAMORA, Milena; INCOGNITO, Anthony V.; VIANNA, Lauro C. Sex differences in blood pressure regulation during ischemic isometric exercise: the role of the β-adrenergic receptors. Journal of Applied Physiology, v. 127, p. 408-414, 2019. DOI: https://doi.org/10.1152/japplphysiol.00270.2019. Disponível em: https://journals.physiology.org/doi/abs/10.1152/japplphysiol.00270.2019.
Abstract:	We sought to investigate whether the β-adrenergic receptors play a pivotal role in sex-related differences in arterial blood pressure (BP) regulation during isometric exercise. Sixteen volunteers (8 women) performed 2 min of ischemic isometric handgrip exercise (IHE) and 2 min of postexercise circulatory occlusion (PECO). Heart rate (HR) and beat-to-beat arterial BP were continuously measured. Beat-to-beat estimates of stroke volume (ModelFlow) were obtained and matched with HR to calculate cardiac output (Q̇) and total peripheral resistance (TPR). Two trials were randomly conducted between placebo and nonselective β-adrenergic blockade (40 mg propranolol). Under the placebo condition, the magnitude of the BP response in IHE was lower in women compared with men. During PECO, the BP remained elevated and the sex differences persisted. The β-blockade attenuated the BP response during IHE in men (∆57 ± 4 vs. ∆45 ± 7 mmHg, P = 0.025) due to a reduction in Q̇ (∆3.7 ± 0.5 vs. ∆1.8 ± 0.2 L/min, P = 0.012) while TPR was not affected. In women, however, the BP response during IHE was unchanged (∆27 ± 3 vs. ∆28 ± 3 mmHg, P = 0.889), despite attenuated Q̇ (∆2.7 ± 0.4 vs. ∆1.3 ± 0.2 L/min, P = 0.012). These responses were mediated by a robust increase in TPR under β-blockade (∆−0.2 ± 0.4 vs. ∆2.2 ± 0.7 mmHg·L−1·min, P = 0.012). These findings demonstrate that the sex differences in arterial BP regulation during ischemic IHE are mediated by β-adrenergic receptors.
Unidade Acadêmica:	Faculdade de Educação Física (FEF)
DOI:	https://doi.org/10.1152/japplphysiol.00270.2019
Versão da editora:	https://journals.physiology.org/doi/abs/10.1152/japplphysiol.00270.2019
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