RESUMO
INTRODUCTION: Adults with obesity are at an increased risk of incident hypertension. Regular aerobic exercise is recommended for the prevention and treatment of hypertension, but whether young adults with obesity exhibit impaired postexercise blood pressure (BP) and vascular responses remains unclear. PURPOSE: We tested the hypothesis that young adults with obesity exhibit attenuated postexercise hypotension (PEH) and postexercise peripheral vasodilation compared with young adults without obesity. METHODS: Thirty-six normotensive adults without and with obesity (11 men and 7 women per group) underwent measurements of brachial and central BP, and leg blood flow (Doppler ultrasound) at baseline and at 30, 60, and 90 min after acute 1-h moderate-intensity cycling. Leg vascular conductance (LVC) was calculated as flow/mean arterial pressure. RESULTS: Both groups exhibited similar brachial and central PEH (peak change from baseline, -2 and -4 mm Hg for brachial and central systolic BPs, respectively, for both groups; time effect, P < 0.05). Both groups also exhibited postexercise peripheral vasodilation, assessed via LVC (time effect, P < 0.05), but its overall magnitude was smaller in young adults with obesity (LVC change from baseline, +47% ± 37%, +29% ± 36%, and +20% ± 29%) compared with young adults without obesity (LVC change from baseline, +88% ± 58%, +59% ± 54%, and +42% ± 51%; group effect, P < 0.05). CONCLUSIONS: Although obesity did not impair PEH after acute moderate-intensity exercise, young adults with obesity exhibited smaller postexercise peripheral vasodilation compared with young adults without obesity. Collectively, these findings have identified evidence for obesity-induced alterations in the peripheral vasculature after exercise.
Assuntos
Pressão Sanguínea/fisiologia , Exercício Físico/fisiologia , Hipertensão/prevenção & controle , Obesidade/fisiopatologia , Vasodilatação/fisiologia , Adulto , Análise de Variância , Determinação da Pressão Arterial/métodos , Composição Corporal , Estudos Transversais , Feminino , Artéria Femoral/fisiologia , Humanos , Perna (Membro)/irrigação sanguínea , Masculino , Hipotensão Pós-Exercício/etiologia , Fluxo Sanguíneo Regional/fisiologiaRESUMO
Unstable blood pressure after spinal cord injury (SCI) is not routinely examined but rather predicted by level and completeness of injury (i.e., American Spinal Injury Association Impairment Scale AIS classification). Our aim was to investigate hemodynamic response to a sit-up test in a large cohort of individuals with chronic SCI to better understand cardiovascular function in this population. Continuous blood pressure and ECG were recorded from individuals with SCI (n = 159) and non-injured individuals (n = 48). We found orthostatic hypotension occurred within each level and AIS classification (n = 36). Moreover, 45 individuals with chronic SCI experienced a drop in blood pressure that did not meet the criteria for orthostatic hypotension, but was accompanied by dramatic increases in heart rate, reflecting orthostatic intolerance. A cluster analysis of hemodynamic response to a seated position identified eight distinct patterns of interaction between blood pressure and heart rate during orthostatic stress indicating varied autonomic responses. Algorithmic cluster analysis of heart rate and blood pressure is more sensitive to diagnosing orthostatic cardiovascular dysregulation. This indicates blood pressure instability cannot be predicted by level and completeness of SCI, and the consensus statement definition of orthostatic hypotension is insufficient to characterize the variability of blood pressure and heart rate responses during orthostatic stress. Both blood pressure and heart rate responses are needed to characterize autonomic function after SCI.
Assuntos
Pressão Sanguínea , Frequência Cardíaca , Hipotensão Pós-Exercício/fisiopatologia , Traumatismos da Medula Espinal/fisiopatologia , Adulto , Sistema Nervoso Autônomo/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Hipotensão Pós-Exercício/etiologia , Traumatismos da Medula Espinal/complicaçõesRESUMO
BACKGROUND: Acute exercise leads to an immediate drop in blood pressure (BP), also called post-exercise hypotension (PEH). Exercise in hypoxia is related to additional vasodilation, potentially contributing to more profound PEH. Therefore, we investigated the impact of hypoxia versus normoxia on the magnitude of PEH. Second, we examined whether these changes in PEH relate to the BP-lowering effects of 12-week exercise training under hypoxia. METHODS: In this prospective study, 21 healthy individuals (age 22.2â±â3.0 years, 14 male) performed a 45-minute high-intensity running exercise on 2 different days in a random order, under hypoxia (fraction of inspired oxygen 14.5%) and normoxia (fraction of inspired oxygen 20.9%). BP was examined pre-exercise (tâ=â0) and at tâ=â15, tâ=â30, tâ=â45, and tâ=â60âminutes post-exercise. Afterward, subjects took part in a 12-week hypoxic running exercise training program. Resting BP was measured before and after the 12-week training program. RESULTS: Acute exercise induced a significant decrease in systolic BP (systolic blood pressure [SBP], Pâ=â.001), but not in diastolic BP (diastolic blood pressure [DBP], Pâ=â.113). No significant differences were observed in post-exercise BP between hypoxic and normoxic conditions (SBP, Pâ=â.324 and DBP, Pâ=â.204). Post-exercise changes in SBP, DBP, and mean arterial pressure significantly correlated to the 12-week exercise training-induced changes in SBP (râ=â0.557, Pâ=â.001), DBP (râ=â0.615, Pâ<â.001), and mean arterial pressure (râ=â0.458, Pâ=â.011). CONCLUSION: Our findings show that hypoxia does not alter the magnitude of PEH in healthy individuals, whilst PEH relates to the BP-lowering effects of exercise. These data highlight the strong link between acute and chronic changes in BP.
Assuntos
Pressão Sanguínea , Treino Aeróbico , Hipóxia , Hipotensão Pós-Exercício/etiologia , Estudos Cross-Over , Feminino , Voluntários Saudáveis , Humanos , Masculino , Adulto JovemRESUMO
Background and objective: Post-exercise hypotension, the reduction of blood pressure after a bout of exercise, is of great clinical relevance. Resistance exercise training is considered an important contribution to exercise training programs for hypertensive individuals and athletes. In this context, post-exercise hypotension could be clinically relevant because it would maintain blood pressure of hypertensive individuals transiently at lower levels during day-time intervals, when blood pressure is typically at its highest levels. The aim of this study was to compare the post-exercise cardiovascular effects on Paralympic powerlifting athletes of two typical high-intensity resistance-training sessions, using either five sets of five bench press repetitions at 90% 1 repetition maximum (1RM) or five sets of three bench press repetitions at 95% 1RM. Materials and Methods: Ten national-level Paralympic weightlifting athletes (age: 26.1 ± 6.9 years; body mass: 76.8 ± 17.4 kg) completed the two resistance-training sessions, one week apart, in a random order. Results: Compared with baseline values, a reduction of 5-9% in systolic blood pressure was observed after 90% and 95% of 1RM at 20-50 min post-exercise. Furthermore, myocardial oxygen volume and double product were only significantly increased immediately after and 5 min post-exercise, while the heart rate was significantly elevated after the resistance training but decreased to baseline level by 50 min after training for both training conditions. Conclusions: A hypotensive response can be expected in elite Paralympic powerlifting athletes after typical high-intensity type resistance-training sessions.
Assuntos
Exercício Físico/fisiologia , Paratletas , Hipotensão Pós-Exercício/etiologia , Levantamento de Peso/fisiologia , Adulto , Pressão Sanguínea/fisiologia , Determinação da Pressão Arterial/métodos , Brasil , Humanos , Masculino , Hipotensão Pós-Exercício/fisiopatologia , Treinamento Resistido/efeitos adversos , Treinamento Resistido/métodos , Levantamento de Peso/lesõesRESUMO
PURPOSE: To investigate the effect of heat stress on postexercise hypotension. METHODS: Seven untrained men, aged 21-33 years, performed two cycling bouts at 60% of oxygen uptake reserve expending 300 kcal in environmental temperatures of 21 °C (TEMP) and 35 °C (HOT) in a randomized, counter-balanced order. Physiological responses were monitored for 10-min before and 60-min after each exercise bout, and after a non-exercise control session (CON). Blood pressure (BP) also was measured during the subsequent 21-h recovery period. RESULTS: Compared to CON, systolic, and diastolic BPs were significantly reduced in HOT (Δ = - 8.3 ± 1.6 and - 9.7 ± 1.4 mmHg, P < 0.01) and TEMP (Δ = - 4.9 ± 2.1 and - 4.5 ± 0.9 mmHg, P < 0.05) during the first 60 min of postexercise recovery. Compared to TEMP, rectal temperature was 0.6 °C higher (P = 0.001), mean skin temperature was 1.8 °C higher (P = 0.013), and plasma volume (PV) was 2.6 percentage points lower (P = 0.005) in HOT. During the subsequent 21-h recovery period systolic BP was 4.2 mmHg lower in HOT compared to CON (P = 0.016) and 2.5 mmHg lower in HOT compared to TEMP (P = 0.039). CONCLUSION: Exercise in the heat increases the hypotensive effects of exercise for at least 22 h in untrained men with elevated blood pressure. Our findings indicate that augmented core and skin temperatures and decreased PV are the main hemodynamic mechanisms underlying a reduction in BP after exercise performed under heat stress.
Assuntos
Ciclismo/estatística & dados numéricos , Exercício Físico , Resposta ao Choque Térmico , Hemodinâmica , Hipertensão/complicações , Hipotensão Pós-Exercício/etiologia , Adulto , Pressão Sanguínea , Determinação da Pressão Arterial , Frequência Cardíaca , Humanos , Masculino , Consumo de Oxigênio , Hipotensão Pós-Exercício/patologia , Adulto JovemRESUMO
The present crossover design study investigated acute hemodynamic responses to two sets of leg press (LP) and bench press (BeP) at 10 and 20 repetition maximum (RM) in ten normotensive young men. At the end of each set, an increase in systolic blood pressure (SBP), heart rate (HR), and rate pressure product (RPP) was observed (p < .01), with no differences between intensities, but SBP was greater during the LP exercise (p < .01). Lower resting values of diastolic blood pressure (DBP) were observed in the post-BeP exercise period (p < .05), suggesting that DBP post-exercise hypotension may be more evident after upper-limb exercise.
Assuntos
Pressão Sanguínea/fisiologia , Exercício Físico/fisiologia , Extremidades , Hipotensão Pós-Exercício , Treinamento Resistido , Adulto , Estudos Cross-Over , Extremidades/irrigação sanguínea , Extremidades/fisiopatologia , Voluntários Saudáveis , Frequência Cardíaca/fisiologia , Hemodinâmica/fisiologia , Humanos , Masculino , Hipotensão Pós-Exercício/diagnóstico , Hipotensão Pós-Exercício/etiologia , Hipotensão Pós-Exercício/fisiopatologia , Treinamento Resistido/efeitos adversos , Treinamento Resistido/métodos , Descanso/fisiologiaRESUMO
PURPOSE: Physical exercise is associated with reduced blood pressure (BP). Moderate-intensity continuous exercise (MCE) promotes post-exercise hypotension (PEH), which is highly recommended to hypertensive patients. However, recent studies with high-intensity interval exercise (HIIE) have shown significant results in cardiovascular disease. Thus, this study aimed to analyze PEH in hypertensive subjects submitted to HIIE and compare it to post MCE hypotension. METHODS: 20 hypertensive adults (51 ± 8 years), treated with antihypertensive medications, were submitted to two different exercise protocols and a control session. The MCE was performed at 60-70% of VO2 reserve, while HIIE was composed of five bouts of 3 min at 85-95% VO2 reserve with 2 min at 50% of VO2 reserve. The following variables were evaluated during exercise, pre- and post-session: clinical BP, heart rate (HR), double product, perception of effort, body mass, height and body mass index. RESULTS: Systolic BP decreased after exercise in both sessions, showing greater decrease after HIIE (- 7 ± 10 and - 11 ± 12 mmHg, after MCE and HIIE, respectively, p ≤ 0.01). Diastolic BP also decreased after both sessions, but there were no significant differences between the two sessions (- 4 ± 8 and - 7 ± 8 mmHg, after MCE and HIIE, respectively). CONCLUSION: Both exercise sessions produced PEH, but HIIE generated a greater magnitude of hypotension. The HIIE protocol performed in this study caused a greater cardiovascular stress during exercise; however, it was safe for the studied population and efficient for reducing BP after exercise.
Assuntos
Treinamento Intervalado de Alta Intensidade/efeitos adversos , Hipotensão Pós-Exercício/etiologia , Adulto , Pressão Sanguínea , Feminino , Frequência Cardíaca , Treinamento Intervalado de Alta Intensidade/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio , Hipotensão Pós-Exercício/fisiopatologiaRESUMO
Paz, GA, Iglesias-Soler, E, Willardson, JM, Maia, MdF, and Miranda, H. Postexercise hypotension and heart rate variability responses subsequent to traditional, paired set, and superset resistance training methods. J Strength Cond Res 33(9): 2433-2442, 2019-The purpose of this study was to compare training volume, postexercise hypotension (PEH), and heart rate variability (HRV) responses to different strength training methods. Thirteen trained men volunteered for this study. Three training methods were completed in a randomized design, which included: Traditional Set (TS)-3 successive sets for the lying bench press (LBP), lat pulldown (LPD), incline 45° bench press (BP45), seated close-grip row (SCR), triceps extension (TE), and biceps curl (BC), with a 90-second rest interval between sets and exercises; Paired Set (PS)-3 paired sets for the LBP-LPD, BP45-SCR, and TE-BC, with a 90-second rest interval between sets and exercises; and superset (SS)-3 supersets for the LBP-LPD, BP45-SCR, and TE-BC. During the SS session, no rest was permitted between PSs, followed by 180 seconds of rest after each SS. Ten repetition-maximum (RM) loads were adopted for all exercises. Blood pressure (BP) and HRV were measured at baseline, immediately aftersession, and at 10-minute intervals until 60 minutes after session. Significantly greater training volume was noted under the SS method (8,608.6 ± 2,062.2 kg) vs. the TS method (7,527.5 ± 2,365.1 kg), respectively. Significantly greater training volume was also observed under the PS method (8,262.3 ± 2,491.2 kg) vs. the TS method (p ≤ 0.05). No main effects for HRV and PEH were noted between protocols (p > 0.05). However, similar PEH response intraprotocols were observed for the TS, PS, and SS methods (p ≤ 0.05). Considering the duration of the PEH intraprotocol, large effect sizes were noted for the SS and PS methods vs. the TS method in diastolic and mean BP. Therefore, both the PS and SS methods may be an alternative to the TS method to achieve greater total repetitions and training volume with a tendency toward a longer PEH response.
Assuntos
Pressão Sanguínea , Frequência Cardíaca , Hipotensão Pós-Exercício/fisiopatologia , Treinamento Resistido/métodos , Adulto , Estudos Cross-Over , Humanos , Masculino , Hipotensão Pós-Exercício/etiologia , Distribuição Aleatória , Treinamento Resistido/efeitos adversos , Descanso/fisiologia , Adulto JovemRESUMO
Fonseca, GF, Farinatti, PTV, Midgley, AW, Ferreira, A, de Paula, T, Monteiro, WD, and Cunha, FA. Continuous and accumulated bouts of cycling matched by intensity and energy expenditure elicit similar acute blood pressure reductions in prehypertensive men. J Strength Cond Res 32(3): 857-866, 2018-This study investigated differences in postexercise hypotension (PEH) after continuous vs. accumulated isocaloric bouts of cycling. Ten prehypertensive men, aged 23-34 years, performed 2 bouts of cycling at 75% oxygen uptake reserve, with total energy expenditures of 400 kcal per bout. One exercise bout was performed continuously (CONTIN) and the other as 2 smaller bouts each expending 200 kcal (INTER1 and INTER2). Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and cardiac autonomic control were monitored in a supine position for 10 minutes before and 60 minutes after each exercise bout, and during a control session. Compared with control, blood pressure was significantly reduced after CONTIN (SBP: [INCREMENT] - 3.4 mm Hg, p < 0.001; MAP: [INCREMENT] - 2.5 mm Hg, p = 0.001), INTER1 (SBP: [INCREMENT] - 2.2 mm Hg, p = 0.045), and INTER2 (SBP: [INCREMENT] - 4.4 mm Hg, p < 0.001; DBP: [INCREMENT] - 2.7 mm Hg, p = 0.045; MAP: [INCREMENT] - 3.3 mm Hg, p = 0.001). The PEH was similar in CONTIN and INTER2, whereas INTER2 elicited greater PEH than INTER1 (SBP and MAP: [INCREMENT] - 2.0 and [INCREMENT] - 1.8 mm Hg, respectively, p ≤ 0.05). Increases in sympathovagal balance from baseline were inversely related to changes in SBP and DBP after CONTIN and INTER2 (r = -0.64 to -0.71; p = 0.021-0.047). These findings indicate that similar amounts of PEH are observed when exercise is performed as a single 400-kcal exercise bout or 2 × 200-kcal bouts and that the exercise recovery pattern of cardiac autonomic activity may be important in eliciting PEH.
Assuntos
Ciclismo/fisiologia , Metabolismo Energético/fisiologia , Esforço Físico/fisiologia , Hipotensão Pós-Exercício/etiologia , Pré-Hipertensão/terapia , Adulto , Frequência Cardíaca/fisiologia , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Pré-Hipertensão/fisiopatologia , Distribuição Aleatória , Adulto JovemRESUMO
OBJECTIVE: The body's adaptation to physical exercise is modulated by sympathetic and parasympathetic (vagal) branches of the autonomic nervous system (ANS). Heart rate variability (HRV), the beat-to-beat variation of the heart, is a proxy measure for ANS activity, whereas blood pressure (BP) is an indicator for cardiovascular function. Impaired vagal activity and lower BP is already described after exercise. However, inconsistent results exist about how long vagal recovery takes and how long post-exercise hypotension persists. Therefore, the aim of this study was to assess HRV and BP 1 h after maximal cardiopulmonary exercise testing (CPET). PATIENTS AND METHODS: HRV (Polar RS800CX), peripheral and central BP (Mobil-O-Graph®) were prospectively studied in 107 healthy volunteers (47 female, median age 29.0 years) in supine position, before and 60 min after maximal CPET. RESULTS: One hour after terminating CPET measures of HRV were still impaired and post-exercise BP was significantly reduced suggesting an improved vascular function compared to pre levels. HRV parameters post-exercise were 34.7% (RMSSD), 67.2% (pNN50), 57.2% (HF), and 42.7% (LF) lower compared to pre-exercise levels (for all p < 0.001). Median reduction in BP was 5 mmHg for systolic BP (p < 0.001), and 4 mmHg for diastolic BP (p = 0.016) and central systolic post-exercise (p = 0.005). CONCLUSIONS: One hour after terminating strenuous exercise, autonomic nervous regulation seems to be postponed which is reflected in reduced HRV, whereas the early recovery of the vasculature, post-exercise hypotension, is still preserved over the recovery period of 1 h.
Assuntos
Coração/fisiologia , Condicionamento Físico Humano/fisiologia , Hipotensão Pós-Exercício/fisiopatologia , Recuperação de Função Fisiológica , Nervo Vago/fisiologia , Adaptação Fisiológica , Pressão Sanguínea , Aptidão Cardiorrespiratória , Vasos Coronários/inervação , Vasos Coronários/fisiologia , Teste de Esforço/métodos , Teste de Esforço/normas , Feminino , Coração/inervação , Humanos , Masculino , Condicionamento Físico Humano/efeitos adversos , Hipotensão Pós-Exercício/etiologiaRESUMO
Despite the fact that simultaneous performance of resistance and aerobic exercises (i.e., concurrent exercise) has become a standard exercise prescription for the elderly, no information is available on its effects on post-exercise hypotension (PEH) in elderly men with hypertension. PURPOSE: To compare the effects of different types of exercise on PEH in elderly men with hypertension. METHODS: Twenty elderly men with essential hypertension participated in three crossover interventions, in random order, and on separate days: a non-exercise control session at seated rest, aerobic exercise performed for 45min, and 45min of concurrent resistance and aerobic exercise consisted of 4 sets of 8 repetitions at 70% 1RM of resistance exercise followed by aerobic exercise on treadmill. After each session, blood pressure (BP) was measured continuously for 1h in the laboratory and for 24h under ambulatory conditions. RESULTS: During the first hour in laboratory, diastolic BP was lower after aerobic (-5mmHg) and concurrent exercise (-6mmHg) in comparison with Control. Day-time diastolic BP was significantly lower after aerobic exercise (-7mmHg) when compared to the control. No significant differences were found among the three experimental sessions for night-time and 24-hour diastolic BP, as well as day-time, night-time and 24-hour systolic BP. CONCLUSION: Concurrent exercise produced acute PEH similar to aerobic exercise but such effect did not last as long as aerobic exercise in elderly patients with essential hypertension.
Assuntos
Pressão Sanguínea , Hipertensão Essencial/fisiopatologia , Exercício Físico , Hipotensão Pós-Exercício/etiologia , Treinamento Resistido/efeitos adversos , Fatores Etários , Idoso , Estudos Cross-Over , Hipertensão Essencial/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Hipotensão Pós-Exercício/diagnóstico , Hipotensão Pós-Exercício/fisiopatologia , Fatores de Risco , Fatores Sexuais , Fatores de TempoRESUMO
Cardiovascular and postural control systems have been studied independently despite the increasing evidence showing the importance of cardiopostural interaction in blood pressure regulation. In this study, we aimed to assess the role of the cardiopostural interaction in relation to cardiac baroreflex in blood pressure regulation under orthostatic stress before and after mild exercise. Physiological variables representing cardiovascular control (heart rate and systolic blood pressure), lower limb muscle activation (electromyography), and postural sway (center of pressure derived from force and moment data during sway) were measured from 17 healthy participants (25 ± 2 yr, 9 men and 8 women) during a sit-to-stand test before and after submaximal exercise. The cardiopostural control (characterized by baroreflex-mediated muscle-pump effect in response to blood pressure changes, i.e., muscle-pump baroreflex) was assessed using wavelet transform coherence and causality analyses in relation to the baroreflex control of heart rate. Significant cardiopostural blood pressure control was evident counting for almost half of the interaction time with blood pressure changes that observed in the cardiac baroreflex (36.6-72.5% preexercise and 34.7-53.9% postexercise). Thus, cardiopostural input to blood pressure regulation should be considered when investigating orthostatic intolerance. A reduction of both cardiac and muscle-pump baroreflexes in blood pressure regulation was observed postexercise and was likely due to the absence of excessive venous pooling and a less stressed system after mild exercise. With further studies using more effective protocols evoking venous pooling and muscle-pump activity, the cardiopostural interaction could improve our understanding of the autonomic control system and ultimately lead to a more accurate diagnosis of cardiopostural dysfunctions.NEW & NOTEWORTHY We examined the interaction between cardiovascular and postural control systems during standing before and after mild exercise. Significant cardiopostural input to blood pressure regulation was shown, suggesting the importance of cardiopostural integration when investigating orthostatic hypotension. In addition, we observed a reduction of baroreflex-mediated blood pressure regulation after exercise.
Assuntos
Barorreflexo , Pressão Sanguínea , Hipotensão Ortostática/fisiopatologia , Músculo Esquelético/irrigação sanguínea , Hipotensão Pós-Exercício/fisiopatologia , Postura , Adulto , Eletromiografia , Teste de Esforço , Feminino , Voluntários Saudáveis , Frequência Cardíaca , Homeostase , Humanos , Hipotensão Ortostática/etiologia , Masculino , Contração Muscular , Hipotensão Pós-Exercício/etiologia , Equilíbrio Postural , Fluxo Sanguíneo Regional , Fatores de Tempo , Transdutores de Pressão , Adulto JovemRESUMO
Evidence indicates that chronic reductions in blood pressure (BP) due to aerobic exercise depend on the ability to induce post-exercise hypotension (PEH) after each training bout. The purpose of this study was to investigate PEH after isocaloric bouts of continuous and accumulated running. 10 healthy pre-hypertensive men (aged 27.6±3.5 years) performed the following bouts of exercise: a) A continuous bout (CONT) expending a total of 400 kcal; and b) An accumulated bout split into 2×200 kcal (INTER1 and INTER2) to total 400 kcal at 75% of oxygen uptake reserve. BP, mean arterial pressure (MAP) and heart rate variability were monitored 10 min before and 60 min after control and all exercise conditions. The decrease in MAP over time after continuous (400 kcal) and accumulated (2×200 kcal) bouts of exercise was more pronounced than during control (mean diff between 1.6 and 5.4 mmHg, P≤0.01), although the magnitude of change was similar between continuous and accumulated bouts (mean diff=0.1 mmHg, P=0.79). Concomitant to the PEH, sympathovagal balance was inversely related to changes in MAP after isocaloric bouts performed continuously and cumulatively (r=- 0.72 and-0.85, P=0.019 and 0.002, respectively). In conclusion, BP decreased to similar levels after continuous and accumulated acute aerobic exercise matched for total energy expenditure. Our findings also indicate that the recovery pattern of cardiac autonomic activity may have an important role in eliciting PEH.
Assuntos
Pressão Sanguínea/fisiologia , Exercício Físico/fisiologia , Hipotensão Pós-Exercício/etiologia , Corrida/fisiologia , Adulto , Metabolismo Energético/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Oxigênio/metabolismo , Pré-Hipertensão/terapia , Fatores de Tempo , Adulto JovemRESUMO
Adequate cerebral perfusion is necessary to maintain consciousness in upright humans. Following maximal anaerobic exercise, cerebral perfusion can become compromised and result in syncope. It is unknown whether post-exercise reductions in cerebral perfusion can lead to visual-cognitive deficits prior to the onset of syncope, which would be of concern for emergency workers and warfighters, where critical decision making and intense physical activity are combined. Therefore, the purpose of this experiment was to determine if reductions in cerebral blood velocity, induced by maximal anaerobic exercise and head-up tilt, result in visual-cognitive deficits prior to the onset of syncope. Nineteen sedentary to recreationally active volunteers completed a symptom-limited 60° head-up tilt for 16 min before and up to 16 min after a 60 sec Wingate test. Blood velocity of the middle cerebral artery was measured using transcranial Doppler ultrasound and a visual decision-reaction time test was assessed, with independent analysis of peripheral and central visual field responses. Cerebral blood velocity was 12.7 ± 4.0% lower (mean ± SE; P < 0.05) after exercise compared to pre-exercise. This was associated with a 63 ± 29% increase (P < 0.05) in error rate for responses to cues provided to the peripheral visual field, without affecting central visual field error rates (P = 0.46) or decision-reaction times for either visual field. These data suggest that the reduction in cerebral blood velocity following maximal anaerobic exercise contributes to visual-cognitive deficits in the peripheral visual field without an apparent affect to the central visual field.
Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Encéfalo/irrigação sanguínea , Cognição/fisiologia , Exercício Físico/fisiologia , Hipotensão Pós-Exercício/diagnóstico , Hipotensão Pós-Exercício/fisiopatologia , Postura/fisiologia , Tempo de Reação/fisiologia , Síncope/etiologia , Adulto , Encéfalo/diagnóstico por imagem , Cognição/classificação , Feminino , Humanos , Masculino , Artéria Cerebral Média/fisiopatologia , Intolerância Ortostática/diagnóstico , Intolerância Ortostática/etiologia , Intolerância Ortostática/fisiopatologia , Hipotensão Pós-Exercício/etiologia , Teste da Mesa Inclinada/métodos , Ultrassonografia Doppler Transcraniana/métodosRESUMO
NEW FINDINGS: What is the central question of this study? Following exercise, hypotension is often reported and syncope is more likely. It is unresolved whether the postexercise hypotension associated with different exercise intensities contributes to the rate at which syncope develops. What is the main finding and its importance? The physiological events that induce presyncope are the same both before and after exercise; however, more intense exercise accelerated the development of hypocapnia, hypotension and, ultimately, syncope. These data indicate that higher intensity exercise induces a postexercise hypotension that reduces cardiovascular reserve, an earlier development of hypocapnia and, ultimately, cerebral hypoperfusion. After exercise, a reduction in mean arterial pressure is often experienced and is referred to as postexercise hypotension. Whilst syncope is more likely following exercise, it is unknown whether orthostatic tolerance is impacted by any exercise intensity-mediated effect on postexercise hypotension. We examined the effect of exercise intensity on time to presyncope, induced via combined head-up tilt and lower body negative pressure following 1 h of cycling at 30 and 70% of heart rate range. Healthy participants (n = 8; mean ± SD, 28 ± 5 years old) completed orthostatic testing to presyncope before and after exercise. Beat-to-beat middle cerebral artery blood flow velocity (MCAv), mean arterial pressure and cerebral oxygenation (measured by near-infrared spectroscopy) were recorded continuously throughout orthostatic testing. During exercise, heart rates were 95 ± 6 and 147 ± 5 beats min(-1) for 30 and 70% heart rate range, respectively, with average power outputs of 103 ± 22 and 221 ± 45 W, respectively. Time to presyncope occurred 32% sooner after the 70% heart rate range trial (952 ± 484 versus 1418 ± 435 s; P = 0.004). Both before and after exercise, presyncope occurred at the same reduction in MCAv (grouped mean, -30 ± 11 cm s(-1) ), mean arterial pressure (-18 ± 13 mmHg), total oxygenation index (-6 ± 2%) and partial pressure of end-tidal CO2 (-16 ± 8 mmHg; all P > 0.1). At presyncope following exercise, the MCAv response was related more to the change in partial pressure of end-tidal CO2 from the baseline preceding orthostatic testing (r(2) = 0.50, P = 0.01) than to the hypotension (r(2) = 0.12, P = 0.17). Presyncope both before and after exercise occurred as a result of the same physiological perturbations, albeit greatly accelerated following more intense exercise.
Assuntos
Exercício Físico/fisiologia , Intolerância Ortostática/diagnóstico , Esforço Físico/fisiologia , Hipotensão Pós-Exercício/diagnóstico , Hipotensão Pós-Exercício/fisiopatologia , Adulto , Velocidade do Fluxo Sanguíneo/fisiologia , Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Intolerância Ortostática/etiologia , Intolerância Ortostática/fisiopatologia , Hipotensão Pós-Exercício/etiologia , Teste da Mesa Inclinada/métodos , Adulto JovemRESUMO
The purpose of this study was to compare the acute effects of 1, 3, and 5 sets of strength training (ST), on heart rate variability (HRV) and blood pressure. Eleven male volunteers (age: 26.1 ± 3.6 years; body mass: 74.1 ± 8.1 kg; height: 172 ± 4 cm) with at least 6 months previous experience in ST participated in the study. After determining the 1 repetition maximum (1RM) load for the bench press (BP), lat pull down (LPD), shoulder press (SP), biceps curl (BC), triceps extension (TE), leg press (LP), leg extension (LE), and leg curl (LC), the participants performed 3 different exercise sequences in a random order and 72 hours apart. During the first sequence, subjects performed a single set of 8-10 repetitions, at 70% 1RM, and with 2-minute rest interval between exercises. Exercises were performed in the following order: BP, LPD, SP, BC, TE, LP, LE, and LC. During the second sequence, subjects performed the same exercise sequence, with the same intensity, 2-minute rest interval between sets and exercises, but with 3 consecutive sets of each exercise. During the third sequence, the same protocol was followed but with 5 sets of each exercise. Before and after the training sessions, blood pressure and HRV were measured. The statistical analysis demonstrated a greater duration of postexercise hypotension after the 5-set program vs. the 1 set or 3 sets (p ≤ 0.05). However, the 5-set program promoted a substantial cardiac stress, as demonstrated by HRV (p ≤ 0.05). These results indicate that 5 sets of 8-10 repetitions at 70% 1RM load may provide the ideal stimulus for a postexercise hypotensive response. Therefore, ST composed of upper- and lower-body exercises and performed with high volumes are capable of producing significant and extended postexercise hypotensive response. In conclusion, strength and conditioning professionals can prescribe 5 sets per exercises if the goal is to reduce blood pressure after training. In addition, these findings may have importance, specifically in the early phase of high blood pressure development, but more research is needed in hypertensive populations to validate this hypothesis.
Assuntos
Pressão Sanguínea , Frequência Cardíaca , Condicionamento Físico Humano/fisiologia , Hipotensão Pós-Exercício/etiologia , Treinamento Resistido/métodos , Adulto , Humanos , Masculino , Condicionamento Físico Humano/métodos , Adulto JovemRESUMO
BACKGROUND: Although exercise training is known to promote post-exercise hypotension, there is currently no consistent argument about the effects of manipulating its various components (intensity, duration, rest periods, types of exercise, training methods) on the magnitude and duration of hypotensive response. OBJECTIVE: To compare the effect of continuous and interval exercises on hypotensive response magnitude and duration in hypertensive patients by using ambulatory blood pressure monitoring (ABPM). METHODS: The sample consisted of 20 elderly hypertensives. Each participant underwent three ABPM sessions: one control ABPM, without exercise; one ABPM after continuous exercise; and one ABPM after interval exercise. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR) and double product (DP) were monitored to check post-exercise hypotension and for comparison between each ABPM. RESULTS: ABPM after continuous exercise and after interval exercise showed post-exercise hypotension and a significant reduction (p < 0.05) in SBP, DBP, MAP and DP for 20 hours as compared with control ABPM. Comparing ABPM after continuous and ABPM after interval exercise, a significant reduction (p < 0.05) in SBP, DBP, MAP and DP was observed in the latter. CONCLUSION: Continuous and interval exercise trainings promote post-exercise hypotension with reduction in SBP, DBP, MAP and DP in the 20 hours following exercise. Interval exercise training causes greater post-exercise hypotension and lower cardiovascular overload as compared with continuous exercise.
Assuntos
Pressão Sanguínea/fisiologia , Terapia por Exercício/métodos , Exercício Físico/fisiologia , Hipotensão Pós-Exercício/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Monitorização Ambulatorial da Pressão Arterial/métodos , Teste de Esforço , Terapia por Exercício/efeitos adversos , Frequência Cardíaca/fisiologia , Hemodinâmica , Humanos , Pessoa de Meia-Idade , Hipotensão Pós-Exercício/etiologia , Valores de Referência , Estatísticas não Paramétricas , Fatores de Tempo , Resultado do TratamentoRESUMO
PURPOSE: This study aimed to investigate the acute effect of intermittent walking exercise (WE) on blood pressure (BP) responses in patients with intermittent claudication (IC). Secondly, this study aimed to gain improved insight into the physiological mechanisms controlling BP regulation after intermittent WE in this patient group. METHODS: Twenty patients with IC participated in two experimental sessions in a random order, as follows: WE (15 × 2-min bouts of WE interpolated with 2-min rest intervals) and control (standing rest on a treadmill for 60 min). BP, cardiac output (CO: CO2 rebreathing), and cardiovascular autonomic modulation (spectral analysis of HR variability) were assessed before and after both experimental sessions during supine rest, and stroke volume (SV) and systemic vascular resistance (SVR) were calculated. Data were analyzed using two-way ANOVA. RESULTS: WE decreased systolic, diastolic, and mean BP, with net effects of -13 ± 2, -5 ± 2, and -7 ± 2 mm Hg versus control, respectively (all P < 0.05). WE also decreased SV (-5.62 ± 1.97 mL, P < 0.05) and CO (-0.05 ± 0.13 L·min(-1), P < 0.05) versus preintervention and prevented the observed increase in SVR in the control condition (+4.2 ± 1.4 U, P < 0.05). HR showed a decrease (P < 0.05), consistent with evidence of increased vagal modulation, in the control condition. BP measurements over the subsequent 24 h were similar between experimental conditions. CONCLUSIONS: In patients with IC, WE induced a postexercise hypotension response that had a significant magnitude versus control but was not maintained over the next 24 h of daily activities. The acute postexercise hypotension response was mediated by a decrease in CO and SV, which was not compensated by an augmentation of SVR, as observed in the control arm of the study.
Assuntos
Claudicação Intermitente/fisiopatologia , Hipotensão Pós-Exercício/etiologia , Caminhada/fisiologia , Pressão Sanguínea , Débito Cardíaco , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Volume Sistólico , Nervo Vago/fisiopatologia , Resistência VascularRESUMO
Due to differences in study populations and protocols, the hemodynamic determinants of post-aerobic exercise hypotension (PAEH) are controversial. This review analyzed the factors that might influence PAEH hemodynamic determinants, through a search on PubMed using the following key words: "postexercise" or "post-exercise" combined with "hypotension", "blood pressure", "cardiac output", and "peripheral vascular resistance", and "aerobic exercise" combined only with "blood pressure". Forty-seven studies were selected, and the following characteristics were analyzed: age, gender, training status, body mass index status, blood pressure status, exercise intensity, duration and mode (continuous or interval), time of day, and recovery position. Data analysis showed that 1) most postexercise hypotension cases are due to a reduction in systemic vascular resistance; 2) age, body mass index, and blood pressure status influence postexercise hemodynamics, favoring cardiac output decrease in elderly, overweight, and hypertensive subjects; 3) gender and training status do not have an isolated influence; 4) exercise duration, intensity, and mode also do not affect postexercise hemodynamics; 5) time of day might have an influence, but more data are needed; and 6) recovery in the supine position facilitates systemic vascular resistance decrease. In conclusion, many factors may influence postexercise hypotension hemodynamics, and future studies should directly address these specific influences because different combinations may explain the observed variability in postexercise hemodynamic studies.
Assuntos
Técnicas de Exercício e de Movimento/efeitos adversos , Exercício Físico/fisiologia , Hemodinâmica/fisiologia , Hipotensão Pós-Exercício/etiologia , Fatores Etários , Pressão Sanguínea/fisiologia , Índice de Massa Corporal , Débito Cardíaco/fisiologia , Humanos , Hipotensão Pós-Exercício/fisiopatologia , Comportamento Sedentário , Fatores Sexuais , Análise e Desempenho de Tarefas , Fatores de Tempo , Resistência Vascular/fisiologiaRESUMO
Due to differences in study populations and protocols, the hemodynamic determinants of post-aerobic exercise hypotension (PAEH) are controversial. This review analyzed the factors that might influence PAEH hemodynamic determinants, through a search on PubMed using the following key words: “postexercise” or “post-exercise” combined with “hypotension”, “blood pressure”, “cardiac output”, and “peripheral vascular resistance”, and “aerobic exercise” combined only with “blood pressure”. Forty-seven studies were selected, and the following characteristics were analyzed: age, gender, training status, body mass index status, blood pressure status, exercise intensity, duration and mode (continuous or interval), time of day, and recovery position. Data analysis showed that 1) most postexercise hypotension cases are due to a reduction in systemic vascular resistance; 2) age, body mass index, and blood pressure status influence postexercise hemodynamics, favoring cardiac output decrease in elderly, overweight, and hypertensive subjects; 3) gender and training status do not have an isolated influence; 4) exercise duration, intensity, and mode also do not affect postexercise hemodynamics; 5) time of day might have an influence, but more data are needed; and 6) recovery in the supine position facilitates systemic vascular resistance decrease. In conclusion, many factors may influence postexercise hypotension hemodynamics, and future studies should directly address these specific influences because different combinations may explain the observed variability in postexercise hemodynamic studies.