Diurnal variation of vascular diameter and reactivity in healthy young men.
Braz J Med Biol Res
; 41(6): 500-3, 2008 Jun.
Article
em En
| MEDLINE
| ID: mdl-18438593
The higher incidence of cardiovascular events in the morning is accompanied by an increased vascular tone. However, there are few published studies designed to evaluate the diurnal variation of vascular and endothelial parameters in healthy subjects. In the present investigation, we evaluated the diurnal variation in brachial artery diameter (BAD), flow-mediated dilation (FMD) and endothelium-independent dilation (NFMD) in a homogeneous sample of healthy non-smoker young men. Fifty subjects aged 20.8 +/- 0.3 years (range: 18 to 25 years) were investigated by brachial artery ultrasound. Exclusion criteria were female gender and evidence of clinically significant health problems, including obesity. Volunteers were asked to rest and avoid fat meals as well as alcoholic beverages 48 h before and until completion of the evaluations. BAD, FMD and NFMD were measured at 7 am, 5 pm, and 10 pm and tested by repeated measures ANOVA. BAD was smaller at 7 am (mean +/- SEM, 3.8 +/- 0.1 mm) in comparison with 5 pm (3.9 +/- 0.1) and 10 pm (4.0 +/- 0.1 mm; P < 0.001). FMD values did not change significantly during the day, while NFMD increased more at 7 am (18.5 +/- 1.1%), when compared to 15.5 +/- 0.9% at 10 pm and 15.5 +/- 0.9% at 5 pm (P = 0.04). The physiological state of vasoconstriction after awakening, with preserved capability to dilate in the morning, should be considered to be part of the healthy cardiovascular adaptation before considering later life risk factors and endothelial dysfunction.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vasoconstrição
/
Artéria Braquial
/
Endotélio Vascular
/
Ritmo Circadiano
Tipo de estudo:
Risk_factors_studies
Limite:
Adolescent
/
Adult
/
Humans
/
Male
Idioma:
En
Revista:
Braz J Med Biol Res
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Brasil