Postexercise hypotension and hemodynamics: the role of exercise intensity.

AIM: Although postexercise hypotension (PEH) has already been extensively demonstrated, the influence of exercise intensity on its magnitude and mechanisms is still controversial. METHODS: Twenty-three normotensive subjects were submitted to a control (45 minutes of rest) and 3 exercise sessions (cycle ergometer, 45 minutes at 30%, 50% and 75% of .VO(2peak)) to investigate the role of exercise intensity on PEH. Blood pressure (BP - auscultatory), heart rate (HR - ECG), and cardiac output (CO - CO2 rebreathing) were measured before and after the control and exercise sessions. RESULTS: Systolic BP decreased significantly after exercise at 50% and 75% of .VO(2peak). Diastolic BP increased significantly during the control session, did not change after exercise at 30% of .VO(2peak), and decreased significantly after exercise at 50% and 75% of .VO(2peak). This fall was greater and longer after more intense exercise. CO and systemic vascular resistance (SVR) responses were similar between sessions, CO increased whereas SVR decreased significantly. Stroke volume (SV) increased and heart rate (HR) decreased following control and exercise at 30% of .VO(2peak) whereas SV decreased and HR increased after exercise at 50% and 75% of .VO(2peak). CONCLUSION: PEH is greater and longer after more intense exercise. BP profile is followed by a decrease in SVR and an increase in CO, what was not influenced by previous exercise. The increase in CO is caused by an increase in SV after rest and low intensity exercise and by an increase in HR after moderate and more intense aerobic exercise.

Factors affecting post-exercise hypotension in normotensive and hypertensive humans.

BACKGROUND: Post-exercise hypotension has been extensively described under laboratory conditions. However, studies investigating the persistence of this post-exercise decrease in blood pressure for longer periods have produced controversial results. The present investigation was conducted to verify the effect of a single bout of exercise on ambulatory blood pressure and to identify potential factors that might influence this post-exercise ambulatory blood pressure fall. DESIGN: The study was a randomized controlled clinical trial. METHODS: Thirty normotensive and 23 hypertensive subjects were submitted to two ambulatory blood pressure monitorings (using the SpaceLabs 90207, SpaceLabs, Redmond, Washington, USA), which were performed after 45min of seated rest (control session) or cycling exercise at 50% peak oxygen uptake (exercise session). RESULTS: Normotensive subjects demonstrated a lower 24h blood pressure level in the exercise session. Hypertensive patients showed no significant difference in ambulatory blood pressure level between the two experimental sessions. Further data analysis revealed that approximately 65% of the subjects in both groups experienced a fall in blood pressure after exercise. Moreover, in the normotensive subjects, this blood pressure fall was significantly and positively correlated with clinic and ambulatory blood pressure, and negatively correlated with weight and body mass index. The blood pressure response to exercise was also greater in women. In the hypertensive patients, the post-exercise blood pressure decrease was significantly and positively correlated with clinic and ambulatory blood pressure as well as with the peak oxygen uptake, and negatively correlated with age and body mass index. CONCLUSIONS: The post-exercise ambulatory blood pressure fall observed in normotensive and hypertensive humans depends on individual characteristics. Moreover, in both normotensive and hypertensive humans, post-exercise ambulatory hypotension is greater in subjects with a higher initial blood pressure level.

[Effect of exercise duration on the magnitude and duration of post-exercise hypotension]. / A duração do exercício determina a magnitude e a duração da hipotensão pós-exercício.

PURPOSE: Considering that exercise duration may play a role in post-exercise hypotension, we tested the hypothesis that a prolonged submaximal exercise would lead to a greater and longer blood pressure fall after exercise than a shorter exercise bout. METHODS: Experimental protocol-10 subjects were submitted to two cycle ergometer exercise trials (25 and 45 min) at 50% of VO2 peak. Control protocol-12 subjects rested in the sitting position for 45 min. Blood pressure (BP) was measured before (20 min) and after (90 min) rest or exercise bouts. RESULTS: Systolic BP decreased significantly after exercise and this reduction was greater and lasted longer after 45 min of exercise. Mean and diastolic BP decreased after exercise and they were significantly lower during the 45 min session. Control protocol--no change in BP was observed after resting condition. CONCLUSION: A longer exercise bout leads to a greater and longer post-exercise hypotension.

A duraçäo do exercício determina a magnitude e a duraçäo da hipotensäo pós-exercício / Exercise duration determines the magnitude and duration of post-exercises hypotension

OBJETIVO - Considerando-se que a duraçÝo do exercício físico possa influenciar a hipotensäo pós-exercício, testamos a hipótese de que o exercício submáximo mais prolongado provoca queda pressória de maior magnitude e duraçäo que o exercício mais curto. MÉTODOS - Protocolo experimental - 10 indivíduos realizaram duas sessöes de exercícios (25 e 45 min) no cicloergômetro em 50 'por cento' VO2 pico. Protocolo controle - 12 indivíduos permaneceram em repouso por 45 min. A pressäo arterial (PA) foi aferida antes (20 min) e após (90 min) o exercício ou o repouso. RESULTADOS - Protocolo experimental - a PA sistólica diminuiu significantemente pós-exercício e essa queda foi maior e mais prolongada após 45 min de exercício. A PA média e a diastólica diminuíram significantemente pós-exercício e foram significantemente menores na sessäo de 45 min. Protocolo controle - a PA näo se alterou durante a sessäo controle. CONCLUSÄO - O exercício físico de maior duraçäo provoca hipotensäo pós-exercício maior e mais prolongada.