Cláudia Lúcia de Moraes Forjaz

Post-exercise changes in blood pressure, heart rate and rate pressure product at different exercise intensities in normotensive humans

To evaluate the effect of exercise intensity on post-exercise cardiovascular responses, 12 young normotensive subjects performed in a randomized order three cycle ergometer exercise bouts of 45 min at 30, 50 and 80% of VO2peak, and 12 subjects rested for 45 min in a non-exercise control trial. Blood pressure (BP) and heart rate (HR) were measured for 20 min prior to exercise (baseline) and at intervals of 5 to 30 (R5-30), 35 to 60 (R35-60) and 65 to 90 (R65-90) min after exercise. Systolic, mean, and diastolic BP after exercise were significantly lower than baseline, and there was no difference between the three exercise intensities. After exercise at 30% of VO2peak, HR was significantly decreased at R35-60 and R65-90. In contrast, after exercise at 50 and 80% of VO2peak, HR was significantly increased at R5-30 and R35-60, respectively. Exercise at 30% of VO2peak significantly decreased rate pressure (RP) product (RP = HR x systolic BP) during the entire recovery period (baseline = 7930 +/- 314 vs R5-30 = 7150 +/- 326, R35-60 = 6794 +/- 349, and R65-90 = 6628 +/- 311, P < 0.05), while exercise at 50% of VO2peak caused no change, and exercise at 80% of VO2peak produced a significant increase at R5-30 (7468 +/- 267 vs 9818 +/- 366, P < 0.05) and no change at R35-60 or R65-90. Cardiovascular responses were not altered during the control trial. In conclusion, varying exercise intensity from 30 to 80% of VO2peak in young normotensive humans did not influence the magnitude of post-exercise hypotension. However, in contrast to exercise at 50 and 80% of VO2peak, exercise at 30% of VO2peak decreased post-exercise HR and RP.

Acute and chronic effects of aerobic and resistance exercise on ambulatory blood pressure

Hypertension is a ubiquitous and serious disease. Regular exercise has been recommended as a strategy for the prevention and treatment of hypertension because of its effects in reducing clinical blood pressure; however, ambulatory blood pressure is a better predictor of target-organ damage than clinical blood pressure, and therefore studying the effects of exercise on ambulatory blood pressure is important as well. Moreover, different kinds of exercise might produce distinct effects that might differ between normotensive and hypertensive subjects. The aim of this study was to review the current literature on the acute and chronic effects of aerobic and resistance exercise on ambulatory blood pressure in normotensive and hypertensive subjects. It has been conclusively shown that a single episode of aerobic exercise reduces ambulatory blood pressure in hypertensive patients. Similarly, regular aerobic training also decreases ambulatory blood pressure in hypertensive individuals. In contrast, data on the effects of resistance exercise is both scarce and controversial. Nevertheless, studies suggest that resistance exercise might acutely decrease ambulatory blood pressure after exercise, and that this effect seems to be greater after low-intensity exercise and in patients receiving anti-hypertensive drugs. On the other hand, only two studies investigating resistance training in hypertensive patients have been conducted, and neither has demonstrated any hypotensive effect. Thus, based on current knowledge, aerobic training should be recommended to decrease ambulatory blood pressure in hypertensive individuals, while resistance exercise could be prescribed as a complementary strategy.

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.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 45min) at 50% of VO2 peak. Control protocol - 12 subjects rested in the sitting position for 45min. Blood pressure (BP) was measured before (20min) and after (90min) rest or exercise bouts. RESULTS: Systolic BP decreased significantly after exercise and this reduction was greater and lasted longer after 45min of exercise. Mean and diastolic BP decreased after exercise and they were significantly lower during the 45min 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.

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

BackgroundPost-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. DesignThe study was a randomized controlled clinical trial. MethodsThirty 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 45 min of seated rest (control session) or cycling exercise at 50% peak oxygen uptake (exercise session). ResultsNormotensive subjects demonstrated a lower 24 h 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. ConclusionsThe 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.

Strength training increases walking tolerance in intermittent claudication patients: Randomized trial

OBJECTIVE To analyze the effects of strength training (ST) in walking capacity in patients with intermittent claudication (IC) compared with walking training (WT) effects. METHODS Thirty patients with IC were randomized into ST and WT. Both groups trained twice a week for 12 weeks at the same rate of perceived exertion. ST consisted of three sets of 10 repetitions of whole body exercises. WT consisted of 15 bouts of 2-minute walking. Before and after the training program walking capacity, peak VO(2), VO(2) at the first stage of treadmill test, ankle brachial index, ischemic window, and knee extension strength were measured. RESULTS ST improved initial claudication distance (358 +/- 224 vs 504 +/- 276 meters; P < .01), total walking distance (618 +/- 282 to 775 +/- 334 meters; P < .01), VO(2) at the first stage of treadmill test (9.7 +/- 2.6 vs 8.1 +/- 1.7 mL.kg(-1).minute; P < .01), ischemic window (0.81 +/- 1.16 vs 0.43 +/- 0.47 mm Hg minute meters(-1); P = .04), and knee extension strength (19 +/- 9 vs 21 +/- 8 kg and 21 +/- 9 vs 23 +/- 9; P < .01). Strength increases correlated with the increase in initial claudication distance (r = 0.64; P = .01) and with the decrease in VO(2) measured at the first stage of the treadmill test (r = -0.52; P = .04 and r = -0.55; P = .03). Adaptations following ST were similar to the ones observed after WT; however, patients reported lower pain during ST than WT (P < .01). CONCLUSION ST improves functional limitation similarly to WT but it produces lower pain, suggesting that this type of exercise could be useful and should be considered in patients with IC.

Clinic and ambulatory blood pressure responses after resistance exercise.

Queiroz, ACC, Gagliardi, JFL, Forjaz, CLM, and Rezk, CC. Clinic and ambulatory blood pressure responses after resistance exercise. J Strength Cond Res 23(2): 571-578, 2009-This study investigated clinic and ambulatory blood pressure (BP) responses after a single bout of low-intensity resistance exercise in normotensive subjects. Fifteen healthy subjects underwent 2 experimental sessions: control-40 minutes of seated rest, and exercise-6 resistance exercises, with 3 sets of as many repetitions as possible until moderate fatigue, with an intensity of 50% of 1-repetition maximum (1RM). Before and for 60 minutes after interventions, clinic BP was measured by auscultatory and oscillometric methods. Postintervention ambulatory BP levels were also measured for 24 hours. In comparison with preintervention values, clinic systolic BP, as measured by the auscultatory method, did not change in the control group, but it decreased after exercise (−3.7 ± 1.6 mm Hg, p < 0.05). Diastolic and mean BP levels increased after intervention in the control group (+3.4 ± 1.0 and +3.0 ± 0.8 mm Hg, respectively, p < 0.05) and decreased in the exercise group (−3.6 ± 1.7 and −3.4 ± 1.4 mm Hg, respectively, p < 0.05). Systolic and mean oscillometric BP levels did not change after interventions either in the control or exercise sessions, whereas diastolic BP increased after intervention in the control group (+5.0 ± 1.7 mm Hg, p < 0.05) but not change after exercise. Ambulatory BP behaviors after interventions were similar in the control and exercise sessions. Significant and positive correlations were observed between preexercise values and postexercise clinic and ambulatory BP decreases. In conclusion, in the whole sample, a single bout of low-intensity resistance exercise decreased postexercise BP under clinic, but not ambulatory, conditions. However, considering individual responses, postexercise clinic and ambulatory hypotensive effects were greater in subjects with higher preexercise BP levels.

A randomized, placebo-controlled trial of the effects of physical exercises and estrogen therapy on health-related quality of life in postmenopausal women

Objective:The purpose of this study was to evaluate the isolated and associated effects of estrogen therapy (estradiol valerate 1 mg/d orally) and physical exercise (moderate aerobic exercise, 3 h/wk) on health-related quality of life (HRQOL) and menopausal symptoms among women who had undergone hysterectomy. Design:A 6-month, randomized, double-blind, placebo-controlled clinical trial with 44 postmenopausal women who had undergone hysterectomy. The interventions were physical exercise and hormone therapy (n = 9), being sedentary and hormone therapy (n = 14), physical exercise and placebo (n = 11), and being sedentary and placebo (n = 10). HRQOL was assessed by a Brazilian standard version of the Medical Outcome Study Short-Form Health Survey and symptoms by Kupperman Index at baseline and after 6 months. Results:There was a decrease in symptoms in all groups, but only groups who performed physical exercise showed an increase in quality of life. Analysis of variance showed that changes in physical functioning (P = 0.001) and bodily pain (P = 0.012) scores over the 6-month period differed significantly between women who exercised and women who were sedentary, regardless of hormone therapy. Hormone therapy had no effect, and there was also no significant association between physical exercise and hormone therapy in HRQOL. Conclusions:Physical exercises can reduce menopausal symptoms and enhance HRQOL, independent of whether hormone therapy is taken.

Comportamento da freqüência cardíaca e da sua variabilidade durante as diferentes fases do exercício físico progressivo máximo

OBJETIVO: A variabilidade da frequencia cardiaca (VFC) tem sido estudada em repouso, como meio nao-invasivo para avaliacao da regulacao autonomica cardiaca, sendo que sua diminuicao esta relacionada a maior risco cardiovascular. Entretanto, durante o exercicio, quando ocorrem importantes alteracoes neurais, seu comportamento deve ser melhor documentado. Estudamos o comportamento da frequencia cardiaca (FC) e da sua variabilidade durante as diferentes fases metabolicas do exercicio fisico progressivo maximo, em jovens. METODOS: Dezessete homens (28±6 anos) realizaram teste ergoespirometrico maximo em cicloergometro (30W/3min), determinando-se a FC e a VFC (desvio-padrao) atraves da onda eletrocardiografica, amplificada e gravada batimento a batimento em computador, numa frequencia da 125Hz (AT/Codas). RESULTADO: A FC aumentou concomitantemente ao aumento da intensidade do exercicio. A VFC diminuiu progressivamente, atingindo niveis significantes em relacao ao repouso a partir de 60% do consumo de oxigenio do pico do exercicio, a partir de 45-60% da potencia maxima e a partir da intensidade do limiar anaerobio, estabilizando-se nos periodos subsequentes. CONCLUSAO: Nossos resultados sugerem que a VFC medida pelo desvio-padrao da FC diminui em fases do exercicio nas quais o aumento da FC e determinado, principalmente, por retirada vagal.

Heart rate recovery: autonomic determinants, methods of assessment and association with mortality and cardiovascular diseases

Cardiovascular disease (CVD) is the primary cause of mortality worldwide. Cardiac autonomic dysfunction seems to be related to the genesis of several CVDs and is also linked to the increased risk of mortality in CVD patients. The quantification of heart rate decrement after exercise – known as heart rate recovery (HRR) – is a simple tool for assessing cardiac autonomic activity in healthy and CVD patients. Furthermore, since The Cleveland Clinic studies, HRR has also been used as a powerful index for predicting mortality. For these reasons, in recent years, the scientific community has been interested in proposing methods and protocols to investigate HRR and understand its underlying mechanisms. The aim of this review is to discuss current knowledge about HRR, including its potential primary and secondary physiological determinants, as well as its role in predicting mortality. Published data show that HRR can be modelled by an exponential curve, with a fast and a slow decay component. HRR may be influenced by population and exercise characteristics. The fast component mainly seems to be dictated by the cardiac parasympathetic reactivation, probably promoted by the deactivation of central command and mechanoreflex inputs immediately after exercise cessation. On the other hand, the slow phase of HRR may be determined by cardiac sympathetic withdrawal, possibly via the deactivation of metaboreflex and thermoregulatory mechanisms. All these pathways seem to be impaired in CVD, helping to explain the slower HRR in such patients and the increased rate of mortality in individuals who present a slower HRR.

Intra-Arterial Blood Pressure Response in Hypertensive Subjects during Low- and High-Intensity Resistance Exercise

OBJECTIVE: The aim of this study was to describe blood pressure responses during resistance exercise in hypertensive subjects and to determine whether an exercise protocol alters these responses. INTRODUCTION: Resistance exercise has been recommended as a complement for aerobic exercise for hypertensive patients. However, blood pressure changes during this kind of exercise have been poorly investigated in hypertensives, despite multiple studies of normotensives demonstrating significant increases in blood pressure. METHODS: Ten hypertensive and ten normotensive subjects performed, in random order, two different exercise protocols, composed by three sets of the knee extension exercise conducted to exhaustion: 40% of the 1-repetition maximum (1RM) with a 45-s rest between sets, and 80% of 1RM with a 90-s rest between sets. Radial intra-arterial blood pressure was measured before and throughout each protocol. RESULTS: Compared with normotensives, hypertensives displayed greater increases in systolic BP during exercise at 80% (+80±3 vs. +62±2 mmHg, P<0.05) and at 40% of 1RM (+75±3 vs. +67±3 mmHg, P<0.05). In both exercise protocols, systolic blood pressure returned to baseline during the rest periods between sets in the normotensives; however, in the hypertensives, BP remained slightly elevated at 40% of 1RM. During rest periods, diastolic blood pressure returned to baseline in hypertensives and dropped below baseline in normotensives. CONCLUSION: Resistance exercise increased systolic blood pressure considerably more in hypertensives than in normotensives, and this increase was greater when lower-intensity exercise was performed to the point of exhaustion.