Folic acid supplementation improves vascular endothelial function, yet not skin blood flow during exercise in the heat, in patients with heart failure.
Am J Physiol Regul Integr Comp Physiol
; 315(4): R810-R819, 2018 10 01.
Article
em En
| MEDLINE
| ID: mdl-29975566
ABSTRACT
Heart failure (HF) patients are susceptible to heat strain during exercise, secondary to blunted skin blood flow (SkBF) responses, which may be explained by impaired nitric oxide (NO)-dependent vasodilation. Folic acid improves vascular endothelial function and SkBF through NO-dependent mechanisms in healthy older individuals and patients with cardiovascular disease. We examined the effect of folic acid supplementation (5 mg/day for 6 wk) on vascular function [brachial artery flow-mediated dilation (FMD)] and SkBF responses [cutaneous vascular conductance (CVC)] during 60 min of exercise at a fixed metabolic heat production (300 WHprod) in a 30°C environment in 10 patients with HF (New York Heart Association Class I-II) and 10 healthy controls (CON). Serum folic acid concentration increased in HF [preintervention (pre) 1.4 ± 0.2; postintervention (post) 8.9 ± 6.7 ng/ml, P = 0.01] and CON (pre 1.3 ± 0.6; post 5.2 ± 4.9 ng/ml, P = 0.03). FMD improved by 2.1 ± 1.3% in HF ( P < 0.01), but no change was observed in CON postintervention ( P = 0.20). During exercise, the external workload performed on the cycle ergometer to attain the fixed level of heat production for exercise was similar between groups (HF 60 ± 13; CON 65 ± 20 external workload, P = 0.52). Increases in CVC during exercise were similar in HF (pre 0.89 ± 0.43; post 0.83 ± 0.45 au/mmHg, P = 0.80) and CON (pre 2.01 ± 0.79; post 2.03 ± 0.72 au/mmHg, P = 0.73), although the values were consistently lower in HF for both pre- and postintervention measurement intervals ( P < 0.05). These findings demonstrate that folic acid improves vascular endothelial function in patients with HF but does not enhance SkBF during exercise at a fixed metabolic heat production in a warm environment.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pele
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Vasodilatação
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Artéria Braquial
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Endotélio Vascular
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Exercício Físico
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Transtornos de Estresse por Calor
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Suplementos Nutricionais
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Ácido Fólico
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Insuficiência Cardíaca
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Temperatura Alta
Tipo de estudo:
Diagnostic_studies
Limite:
Aged
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Am J Physiol Regul Integr Comp Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Austrália