Hemodynamic and autonomic correlates of postexercise hypotension in patients with mild hypertension

Abstract

In 15 middle-aged patients with mild essential hypertension, we evaluated blood pressure (BP), cardiac output (CO), total peripheral resistance (TPR), forearm (FVR) and calf vascular resistance (CVR), and autonomic function [by spectral analysis of R-R interval and BP variabilities and spontaneous baroreflex sensitivity (BRS)] before and after maximal exercise. Systolic and diastolic BP, TPR, and CVR were significantly reduced from baseline 60-90 min after exercise. CO, FVR, and HR were unchanged. The low-frequency (LF) component of BP variability increased significantly after exercise, whereas the LF component of R-R interval variability was unchanged. The overall change in BRS was not significant after exercise vs. baseline, although a significant, albeit small, BRS increase occurred in response to hypotensive stimuli. These findings indicate that in hypertensive patients, PEH is mediated mainly by a peripheral vasodilation, which may involve metabolic factors linked to postexercise hyperemia in the active limbs. The vasodilator effect appears to override a concomitant, reflex sympathetic activation selectively directed to the vasculature, possibly aimed to counter excessive BP decreases. The cardiac component of arterial baroreflex is reset during PEH, although the baroreflex mechanisms controlling heart period appear to retain the potential for greater opposition to hypotensive stimuli.

Accumulation of physical activity: blood pressure reduction between 10-min walking sessions

“…9,11,12 As a result of the accumulation of four 10-min sessions of PA over a 4-h period, 9 the reduction in BP was correlated with changes in autonomic modulation; although in this study, autonomic modulation during the rest period did not appear to be affected by 10-min sessions of PA in our study even though we found changes in systolic BP. These findings are similar to those reported by Legramante et al 24 who found no significant changes in autonomic modulation, although they elicited a significant 11.9 mm Hg reduction in systolic BP and a 5.3 mm Hg reduction in diastolic BP. In their study, 24 both post-exercise (graded exercise to 87% of predicted maximum heart rate) BP and HRV were measured for 5 min between 60 to 90 min following a single session of exercise.…”

“…These findings are similar to those reported by Legramante et al 24 who found no significant changes in autonomic modulation, although they elicited a significant 11.9 mm Hg reduction in systolic BP and a 5.3 mm Hg reduction in diastolic BP. In their study, 24 both post-exercise (graded exercise to 87% of predicted maximum heart rate) BP and HRV were measured for 5 min between 60 to 90 min following a single session of exercise. Also, Pober et al 25 found no significant increase in parasympathetic activity at 1, 3 and 6 h after 60 min of cycle ergometry at 65% of VO 2 peak.…”

Influência do treinamento aeróbio nos mecanismos fisiopatológicos da hipertensão arterial sistêmica

“…Estudos têm relatado redução da pressão arterial em indivíduos normotensos e hipertensos após uma única sessão de exercício físico (BROWLEY et al, 2003;KULICS;DICARLO, 1999;LEGRAMANTE et al, 2002;RONDON;BRUM, 2003;SENITKO;CHARKOUDIAN;HALLIWIL, 2002). Embora a hipotensão pós-exercício (HPE) seja detectada em normotensos, nesses indivíduos a resposta pressórica parece ser menos consistente e de menor magnitude do que em indivíduos hipertensos (MACDONALD, 2002).…”

“…Alguns autores postulam que o mecanismo da HPE esteja ligado à redução da RVP (LEGRAMANTE et al, 2002), redução da atividade simpática (BROWLEY et al, 2003;KULICS;DICARLO, 1999) e redução do débito cardíaco associado ao menor volume sistólico (NEGRÃO; RONDON, 2001;RONDON;BRUM, 2003). Segundo Halliwill (2001) a HPE resulta da redução na RVP, mediada pelo sistema nervoso autônomo e substâncias vasodilatadoras.…”

Efeitos do treinamento intervalado na resposta hipotensiva de militares com diferentes padrões de condicionamento físico

“…Em se tratando do parâmetro intensidade do exercício, estudos relatam diferentes efeitos agudos do exercício aeróbio na redução dos níveis pressóricos de seus praticantes, após uma única sessão de exercícios físicos (BROWLEY et al, 2003;KULICS;COLLINS;DICARLO, 1999;JONES et al, 2007;LEGRAMANTE et al, 2002;RONDON;BRUM, 2003;SENITKO;CHARKOUDIAN;HALLIWIL, 2002). Jones et al (2007) O controle da intensidade do TIA é baseado no resultado do indivíduo em um teste de corrida de 12 min (COOPER, 1968).…”