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This study aimed to test whether bright light (BL) exposure attenuates the reduction in blood pressure (BP) postexercise compared to dim light (DL). Twenty healthy men (27 ± 5 years) randomly underwent two experimental sessions: one under BL (5000 lux) and another under dim light (DL <8lux). In each session, subjects executed a bout of aerobic exercise (cycle ergometer, 30 min, moderate intensity). BP (oscillometric) and heart rate (HR monitor) were measured, and rate-pressure-product (RPP) was calculated. Additionally, a 24-h ambulatory blood pressure monitoring (ABPM) was conducted after the sessions. Systolic BP decreased while HR increased significantly and similarly after the exercise in both sessions. Additionally, systolic BP levels were higher in BL than DL throughout the experimental session (Psession = 0.04). Diastolic (Pinteraction = 0.02) and mean (Pinteraction = 0.03) BPs decreased after exercise in DL (at 30 min), and increased in BL (at 60 and 90 min). RPP increased in both sessions postexercise, but with a main effect revealing higher levels throughout the experimental session in BL than DL (Psession = 0.04) and during the first 3 h of ABPM (p = 0.05). In healthy men, BL exposure increased systolic BP and cardiac work, and abolished the postexercise decreases of diastolic and mean BPs.
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Pressão Sanguínea , Exercício Físico , Frequência Cardíaca , Humanos , Masculino , Exercício Físico/fisiologia , Pressão Sanguínea/fisiologia , Adulto , Frequência Cardíaca/fisiologia , Luz , Monitorização Ambulatorial da Pressão Arterial/métodos , Adulto JovemRESUMO
The blood pressure-lowering effect of aerobic training is preceded by improving cardiovascular autonomic control. We previously demonstrated that aerobic training conducted in the evening (ET) induces a greater decrease in blood pressure than morning training (MT). To study whether the greater blood pressure decrease after ET occurs through better cardiovascular autonomic regulation, this study aimed to compare MT versus ET on muscle sympathetic nerve activity (MSNA) and baroreflex sensitivity (BRS) in treated patients with hypertension. Elderly patients treated for hypertension were randomly allocated into MT (n = 12, 07.00-10.00 h) or ET (n = 11, 17.00-20.00 h) groups. Both groups trained for 10 weeks, 3 times/week, cycling for 45 min at moderate intensity. Beat-to-beat blood pressure (finger photoplethysmography), heart rate (electrocardiography) and MSNA (microneurography) were assessed at the initial and final phases of the study at baseline and during sequential bolus infusions of sodium nitroprusside and phenylephrine (modified-Oxford technique) to evaluate cardiac and sympathetic BRS. Mean blood pressure decreased significantly after ET but not after MT (-9 ± 11 vs. -1 ± 8 mmHg, P = 0.042). MSNA decreased significantly only after ET with no change after MT (-12 ± 5 vs. -3 ± 7 bursts/100 heart beats, P = 0.013). Sympathetic BRS improved after ET but not after MT (-0.8 ± 0.7 vs. 0.0 ± 0.8 bursts/100 heart beats/mmHg, P = 0.052). Cardiac BRS improved similarly in both groups (ET: +1.7 ± 1.8 vs. MT: +1.4 ± 1.9 ms/mmHg, Pphase ≤ 0.001). In elderly patients treated for hypertension, only ET decreased mean blood pressure and MSNA and improved sympathetic BRS. These findings revealed that the sympathetic nervous system has a key role in ET's superiority to MT in blood pressure-lowering effect. KEY POINTS: Reducing muscle nerve sympathetic activity and increasing sympathetic baroreflex sensitivity plays a key role in promoting the greater blood pressure reduction observed with evening training. These findings indicated that simply changing the timing of exercise training may offer additional benefits beyond antihypertensive medications, such as protection against sympathetic overdrive and loss of baroreflex sensitivity, independent markers of mortality. Our new findings also suggest new avenues of investigation, such as the possibility that evening aerobic training may be beneficial in other clinical conditions with sympathetic overdrive, such as congestive heart failure and hypertrophic cardiomyopathy.
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Sistema Cardiovascular , Hipertensão , Humanos , Idoso , Barorreflexo/fisiologia , Hipertensão/terapia , Pressão Sanguínea/fisiologia , Coração , Sistema Nervoso Simpático/fisiologia , Frequência Cardíaca/fisiologia , Músculo EsqueléticoRESUMO
Although dynamic resistance training (DRT) and isometric handgrip training (IHT) may decrease blood pressure (BP) in hypertensives, the effects of these types of training have not been directly compared, and a possible additive effect of combining IHT to DRT (combined resistance training-CRT), has not been investigated. Thus, this study compared the effects of DRT, IHT and CRT on BP, systemic hemodynamics, vascular function, and cardiovascular autonomic modulation. Sixty-two middle-aged men with treated hypertension were randomly allocated among four groups: DRT (8 exercises, 50% of 1RM, 3 sets until moderate fatigue), IHT (30% of MVC, 4 sets of 2 min), CRT (DRT + IHT) and control (CON - stretching). In all groups, the interventions were administered 3 times/week for 10 weeks. Pre- and post-interventions, BP, systemic hemodynamics, vascular function and cardiovascular autonomic modulation were assessed. ANOVAs and ANCOVAs adjusted for pre-intervention values were employed for analysis. Systolic BP decreased similarly with DRT and CRT (125 ± 11 vs. 119 ± 12 and 128 ± 12 vs. 119 ± 12 mmHg, respectively; P < 0.05), while peak blood flow during reactive hyperaemia (a marker of microvascular function) increased similarly in these groups (774 ± 377 vs. 1067 ± 461 and 654 ± 321 vs. 954 ± 464 mL/min, respectively, P < 0.05). DRT and CRT did not change systemic hemodynamics, flow-mediated dilation, and cardiovascular autonomic modulation. In addition, none of the variables were changed by IHT. In conclusion, DRT, but not IHT, improved BP and microvascular function in treated hypertensive men. CRT did not have any additional effect in comparison with DRT alone.
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Hipertensão , Treinamento Resistido , Masculino , Pessoa de Meia-Idade , Humanos , Pressão Sanguínea/fisiologia , Força da Mão/fisiologia , Hipertensão/terapia , Hemodinâmica/fisiologiaRESUMO
Patients with peripheral artery disease (PAD) have reduced muscle capillary density. Walking training (WT) is recommended for PAD patients. The goal of the study was to verify whether WT promotes angiogenesis in PAD-affected muscle and to investigate the possible role of miRNA-126 and the vascular endothelium growth factor (VEGF) angiogenic pathways on this adaptation. Thirty-two men with PAD were randomly allocated to two groups: WT (n = 16, 2 sessions/week) and control (CO, n = 16). Maximal treadmill tests and gastrocnemius biopsies were performed at baseline and after 12 weeks. Histological and molecular analyses were performed by blinded researchers. Maximal walking capacity increased by 65% with WT. WT increased the gastrocnemius capillary-fiber ratio (WT = 109 ± 13 vs. 164 ± 21 and CO = 100 ± 8 vs. 106 ± 6%, p < 0.001). Muscular expression of miRNA-126 and VEGF increased with WT (WT = 101 ± 13 vs. 130 ± 5 and CO = 100 ± 14 vs. 77 ± 20%, p < 0.001; WT = 103 ± 28 vs. 153 ± 59 and CO = 100 ± 36 vs. 84 ± 41%, p = 0.001, respectively), while expression of PI3KR2 decreased (WT = 97 ± 23 vs. 75 ± 21 and CO = 100 ± 29 vs. 105 ± 39%, p = 0.021). WT promoted angiogenesis in the muscle affected by PAD, and miRNA-126 may have a role in this adaptation by inhibiting PI3KR2, enabling the progression of the VEGF signaling pathway.
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MicroRNAs , Doença Arterial Periférica , Masculino , Humanos , Claudicação Intermitente/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Doença Arterial Periférica/genética , Doença Arterial Periférica/metabolismo , Músculo Esquelético/metabolismo , Caminhada/fisiologia , MicroRNAs/genética , MicroRNAs/metabolismoRESUMO
Background: Post-dynamic resistance exercise hypotension (PREH) has been largely demonstrated. However, little is known regarding the interindividual variation of PREH magnitude and its predictors (i.e. factors of influence). Aims: To assess the interindividual variation of PREH and its predictors related to the characteristics of the individuals and the exercise protocol. Methods: This study retrospectively analysed data from 131 subjects included in seven controlled trials about PREH (including at least one dynamic resistance exercise and one control session) conducted by two research laboratories. The interindividual variation was assessed by the standard deviation of the individual responses (SD IR), and linear regression analyses were conducted to explore the predictors. Results: PREH showed moderate interindividual variation for systolic (SBP, SD IR=4.4mmHg; 0.35 standardised units) and diastolic blood pressures (DBP, SD IR=3.6mmHg; 0.32 standardised units). For systolic PREH, multivariate regression analysis (R 2=0.069) revealed higher baseline SBP (B=-0.157, p=0.008) and higher number of sets (B=-3.910, p=0.041) as significant predictors. For diastolic PREH, multivariate regression analysis (R 2=0.174) revealed higher baseline DBP (B=-0.191, p=0.001) and higher exercise volume (i.e. number of exercises *sets per exercise *repetitions per sets >150; B=-4.212, p=0.001) as significant predictors. Conclusion: PREH has a considerable interindividual variation. Greater PREH magnitude is observed in individuals with higher baseline blood pressure and after exercise protocols that comprehend higher number of sets and exercise volume.
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Hypertensives present cardiac autonomic dysfunction. Reduction in sleep quality increases blood pressure (BP) and favors hypertension development. Previous studies suggested a relationship between cardiovascular autonomic dysfunction and sleep quality, but it is unclear whether this association is present in hypertensives. Thus, this study evaluated the relationship between sleep quality and cardiac autonomic modulation in hypertensives. Forty-seven middle-aged hypertensive men under consistent anti-hypertensive treatment were assessed for sleep quality by the Pittsburgh Sleep Quality Index (PSQI-higher score means worse sleep quality). Additionally, their beat-by-beat BP and heart rate (HR) were recorded, and cardiac autonomic modulation was assessed by their variabilities. Mann-Whitney and t tests were used to compare different sleep quality groups: poor (PSQI > 5, n = 24) vs good (PSQI ≤ 5, n = 23), and Spearman's correlations to investigate associations between sleep quality and autonomic markers. Patients with poor sleep quality presented lower cardiac parasympathetic modulation (HR high-frequency band = 26 ± 13 vs 36 ± 15 nu, P = .03; HR total variance = 951 ± 1373 vs 1608 ± 2272 ms2 , P = .05) and cardiac baroreflex sensitivity (4.5 ± 2.3 vs 7.1 ± 3.7 ms/mm Hg, P = .01). Additionally, sleep quality score presented significant positive correlation with HR (r = +0.34, P = .02) and negative correlations with HR high-frequency band (r = -0.34, P = .03), HR total variance (r = -0.35, P = .02), and cardiac baroreflex sensitivity (r = -0.42, P = .01), showing that poor sleep quality is associated with higher HR and lower cardiac parasympathetic modulation and baroreflex sensitivity. In conclusion, in treated hypertensive men, poor sleep quality is associated with cardiac autonomic dysfunction.
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Hipertensão , Sistema Nervoso Autônomo , Barorreflexo , Pressão Sanguínea , Frequência Cardíaca , Humanos , Hipertensão/complicações , Hipertensão/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , SonoRESUMO
Introduction: Despite growing evidence regarding the benefits of resistance training in hypertension, the large and abrupt rise of systolic blood pressure (SBP) observed during resistance exercise execution has resulted in concern about its safety. However, the manipulation of the resistance training protocol (RTP) organization, maintaining the work to rest ratio equated between protocols (W:R-equated), may reduce the SBP increase. Purpose: To compare cardiovascular responses during two W:R-equated RTPs (3 × 15:88 s vs. 9 × 5:22 s - sets × reps: rest between sets) performed in exercises for the lower and upper limbs. Methods: Twelve medicated hypertensives (48 ± 8 years) randomly performed two RTPs in the bilateral leg extension (BLE) and unilateral elbow flexion (UEF) exercises at 50% 1RM. Increases (Δ) of SBP, heart rate (HR) and rate pressure product (RPP) during the exercises were measured by photoplethysmography. Results: In both BLE and UEF exercises, Δ SBP was significantly greater during 3 × 15:88 s than 9 × 5:22 s (peak values: BLE = + 84 ± 39 vs. + 67 ± 20 mm Hg, and UEF = + 46 ± 25 vs. + 37 ± 18 mm Hg, respectively, both p < 0.05). ΔHR and ΔRPP were significantly higher in the 3 × 15:88 s than 9 × 5:22 s in BLE (peak values + 45 ± 17 vs. + 30 ± 8 bpm, and + 15,559 ± 5570 vs. + 10,483 ± 2614 mm Hg. bpm). Conclusion: In medicated hypertensives, a RTP combining more sets with less repetitions per set and shorter rest intervals between sets (i.e., 9 × 5:22 s) produced a smaller increase in cardiovascular load (ΔSBP, ΔHR and ΔRPP) during its execution than a protocol with fewer longer sets (i.e., 3 × 15:88 s).
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BACKGROUND: Post-exercise hypotension (PEH) is greater after evening than morning exercise, but antihypertensive drugs may affect the evening potentiation of PEH. Objective: To compare morning and evening PEH in hypertensives receiving angiotensin-converting enzyme inhibitors (ACEi) or angiotensin II receptor blockers (ARB). METHODS: Hypertensive men receiving ACEi (n = 14) or ARB (n = 15) underwent, in a random order, two maximal exercise tests (cycle ergometer, 15 watts/min until exhaustion) with one conducted in the morning (7 and 9 a.m.) and the other in the evening (8 and 10 p.m.). Auscultatory blood pressure (BP) was assessed in triplicate before and 30 min after the exercises. Changes in BP (post-exercise - pre-exercise) were compared between the groups and the sessions using a two-way mixed ANOVA and considering P < .05 as significant. RESULTS: In the ARB group, systolic BP decrease was greater after the evening than the morning exercise, while in the ACEi group, it was not different after the exercises conducted at the different times of the day. Additionally, after the evening exercise, systolic BP decrease was lower in the ACEi than the ARB group (ARB = -11 ± 8 vs -6 ± 6 and ACEi = -6 ± 7 vs. -8 ± 5 mmHg, evening vs. morning, respectively, P for interaction = 0.014). CONCLUSIONS: ACEi, but not ARB use, blunts the greater PEH that occurs after exercise conducted in the evening than in the morning.
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Antagonistas de Receptores de Angiotensina/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Hipotensão Pós-Exercício/tratamento farmacológico , Adulto , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Exercício Físico/fisiologia , Terapia por Exercício , Humanos , Masculino , Pessoa de Meia-Idade , Hipotensão Pós-Exercício/fisiopatologia , Adulto JovemRESUMO
INTRODUCTION: Previous studies observed diurnal variation in hemodynamic responses during recovery from whole-body exercise, with vasodilation appearing greater after evening versus morning sessions. It is unclear what mechanism(s) underlie this response. Since small muscle-mass exercise can isolate peripheral effects related to postexercise vasodilation, it may provide insight into possible mechanisms behind this diurnal variation. METHODS: The study was conducted in ten healthy (5F, 5M) young individuals, following single-leg dynamic knee-extension exercise performed in the Morning (7:30-11:30 am) or the Evening (5-9 pm) on two different days, in random order. Arterial pressure (automated auscultation) and leg blood flow (femoral artery Doppler ultrasound) were measured pre-exercise and during 120 min postexercise. Net effect for each session was calculated as percent change in blood flow (or vascular conductance) between the Active Leg and the Inactive Leg. RESULTS: Following Morning exercise, blood flow was 34.9 ± 8.9% higher in the Active Leg versus the Inactive Leg (p < 0.05) across recovery. Following Evening exercise, blood flow was 35.0 ± 8.8% higher in the Active Leg versus the Inactive Leg (p < 0.05). Likewise, vascular conductance was higher in the Active Leg versus the Inactive Leg (Morning: +35.1 ± 9.0%, p < 0.05; Evening: +33.2 ± 8.2%, p < 0.05). Morning and Evening blood flow (p = 0.66) and vascular conductance (p = 0.64) did not differ. CONCLUSION: These data suggest previous studies which identified diurnal variations in postexercise vasodilation responses are likely reflecting central rather than peripheral modulation of cardiovascular responses.
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INTRODUCTION: The acute blood pressure (BP) decrease is greater after evening than morning exercise, suggesting that evening training (ET) may have a greater hypotensive effect. OBJECTIVE: This study aimed to compare the hypotensive effect of aerobic training performed in the morning versus evening in treated hypertensives. METHODS: Fifty treated hypertensive men were randomly allocated to three groups: morning training (MT), ET, and control (C). Training groups cycled for 45 min at moderate intensity (progressing from the heart rate of the anaerobic threshold to 10% below the heart rate of the respiratory compensation point), while C stretched for 30 min. Interventions were conducted 3 times per week for 10 wk. Clinic and ambulatory BP and hemodynamic and autonomic mechanisms were evaluated before and after the interventions. Clinic assessments were performed in the morning (7:00-9:00 AM) and evening (6:00-8:00 PM). Between-within ANOVA was used (P ≤ 0.05). RESULTS: Only ET decreased clinic systolic BP differently from C and MT (morning assessment -5 ± 6 mm Hg and evening assessment -8 ± 7 mm Hg, P < 0.05). Only ET reduced 24 h and asleep diastolic BP differently from C and MT (-3 ± 5 and -3 ± 4 mm Hg, respectively, P < 0.05). Systemic vascular resistance decreased from C only in ET (P = 0.03). Vasomotor sympathetic modulation decreased (P = 0.001) and baroreflex sensitivity (P < 0.02) increased from C in both training groups with greater changes in ET than MT. CONCLUSIONS: In treated hypertensive men, aerobic training performed in the evening decreased clinic and ambulatory BP due to reductions in systemic vascular resistance and vasomotor sympathetic modulation. Aerobic training conducted at both times of day increases baroreflex sensitivity, but with greater after ET.
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Pressão Sanguínea/fisiologia , Exercício Físico/fisiologia , Hipertensão/fisiopatologia , Condicionamento Físico Humano , Adulto , Anti-Hipertensivos/uso terapêutico , Barorreflexo/fisiologia , Humanos , Hipertensão/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Resistência Vascular/fisiologia , Sistema Vasomotor/fisiologiaRESUMO
Paulo, AC, Tricoli, V, Queiroz, ACC, Laurentino, G, and Forjaz, CLM. Blood pressure response during resistance training of different work-to-rest ratio. J Strength Cond Res 33(2): 399-407, 2019-Changes in the work-to-rest ratio (W:R) of resistance training protocols (RTPs) (i.e., decreasing work or increasing rest) reduce the marked elevation in blood pressure (BP) that occurs during RTP execution. However, whether changes in RTP structure without changing W:R can change BP responses to RTP is unknown. To investigate the effect of different structures of rest intervals and number of repetitions per set on BP response among RTP equated and nonequated for W:R, 20 normotensive participants (25 ± 4 years) performed 4 different RTP of the leg extension exercise with the same work but different W:R structures. Two protocols followed the recommendations for cardiovascular disorders: (a) HIGHW:R-3×15:44s-3×15:44s (set×reps:rest between sets), which has high W:R (45reps:88s) and (b) LOWW:R-3×15:88s-3×15:88s, which has low W:R (45reps:176s). The other 2 protocols were W:R-equated to LOWW:R (45reps:176s): (c) LOWW:R-9×5:22s and (d) LOWW:R-45×1:4s. Systolic BP (ΔSBP) and diastolic BP (ΔDBP) were assessed by finger photoplethysmography. There were significant main effects for ΔSBP after RTP (p ≤ 0.05): HIGHW:R-3×15:44s = LOWW:R-3×15:88s > LOWW:R-45×1:4s > LOWW:R-9×5:22s (+87 ± 5 and +84 ± 5 vs. +61 ± 4 vs. 57 ± 4 mm Hg). For ΔDBP, there was a significant interaction between RTP and moment (p ≤ 0.05). Thus, HIGHW:R-3×15:44 > LOWW:R-3×15:88s > LOWW:R-45×1:4s > LOWW:R-9×5:22s (+53 ± 5 vs. +49 ± 5 vs. +44 ± 4 vs. +38 ± 3 mm Hg). HIGHW:R-3×15:44s produced the highest increase in ΔDBP, and LOWW:R-9×5:22s produced the lowest increase in ΔSBP and ΔDBP. Our findings may help the development of RTP protocols that may mitigate pressure peaks without changing important exercise variables (i.e., volume or duration).
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Pressão Sanguínea/fisiologia , Doenças Cardiovasculares/fisiopatologia , Treinamento Resistido/métodos , Descanso/fisiologia , Adulto , Exercício Físico/fisiologia , Feminino , Humanos , Masculino , Adulto JovemRESUMO
OBJECTIVE: The purpose of this paper is to introduce the overarching study design of the South American Youth/Child Cardiovascular and Environmental (SAYCARE) study, which is an observational multicenter feasibility study held in seven South American cities: Buenos Aires (Argentina), Lima (Peru), Medellin (Colombia), Montevideo (Uruguay), Santiago (Chile), and São Paulo and Teresina (Brazil). Children and adolescents (3-17 years of age) were studied. METHODS: The data management systems, quality assurance monitoring activities, standardized operating procedure manuals, and training and study management are addressed in this paper. Various quality controls to ensure the collection of valid and reliable data are also discussed. RESULTS AND CONCLUSIONS: Data were obtained from 237 preschoolers and schoolchildren and 258 adolescents during the validation phase measurements. The results of the SAYCARE study are expected to provide higher accuracy in the assessment of cardiovascular disease risk factors, including eating behaviors, body composition, physical activity, sedentary behaviors, lipid profiles and cardiovascular health biomarkers, oral health, social conditions, environmental factors and home environment, and their determinants in children and adolescents from ages 3 to 17 in seven South American cities.
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Doenças Cardiovasculares/epidemiologia , Meio Ambiente , Projetos de Pesquisa Epidemiológica , Objetivos , Adolescente , Sistema Cardiovascular/fisiopatologia , Criança , Pré-Escolar , Comportamento Alimentar/fisiologia , Feminino , Humanos , Estilo de Vida/etnologia , Masculino , Fatores de Risco , Fatores Socioeconômicos , América do Sul/epidemiologiaRESUMO
OBJECTIVE: The objective of this article is to test the reliability and validity of the new and innovative physical activity (PA) questionnaire. METHODS: Subsamples from the South American Youth/Child Cardiovascular and Environment Study (SAYCARE) study were included to examine its reliability (children: n = 161; adolescents: n = 177) and validity (children: n = 82; adolescents: n = 60). The questionnaire consists of three dimensions of PA (leisure, active commuting, and school) performed during the last week. To assess its validity, the subjects wore accelerometers for at least 3 days and 8 h/d (at least one weekend day). The reliability was analyzed by correlation coefficients. In addition, Bland-Altman analysis and a multilevel regression were applied to estimate the measurement bias, limits of agreement, and influence of contextual variables. RESULTS: In children, the questionnaire showed consistent reliability (ρ = 0.56) and moderate validity (ρ = 0.46), and the contextual variable variance explained 43.0% with -22.9 min/d bias. In adolescents, the reliability was higher (ρ = 0.76) and the validity was almost excellent (ρ = 0.88), with 66.7% of the variance explained by city level with 16.0 min/d PA bias. CONCLUSIONS: The SAYCARE PA questionnaire shows acceptable (in children) to strong (in adolescents) reliability and strong validity in the measurement of PA in the pediatric population from low- to middle-income countries.
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Exercício Físico/fisiologia , Inquéritos e Questionários , Adolescente , Criança , Pré-Escolar , Projetos de Pesquisa Epidemiológica , Feminino , Humanos , Atividades de Lazer , Masculino , Reprodutibilidade dos Testes , Instituições Acadêmicas/estatística & dados numéricos , América do Sul/epidemiologia , Inquéritos e Questionários/normasRESUMO
The aim of this study was to compare the effects of a single session of walking and combined exercise on oxidative stress and vascular function in peripheral arterial disease patients. Thirteen patients with peripheral arterial disease underwent two experimental sessions in random order: walking (ten sets of 2-min walking at the speed corresponding to the onset of claudication pain with 2-min interval between sets) and combined exercise (1 × 10 reps in eight resistance exercises plus five-two-minute sets of walking). Before and after the exercise, vascular function (blood flow, leg vascular resistance and blood-flow postreactive hyperaemia) and oxidative stress (malondialdehyde and plasma nitrite levels) were obtained. Blood flow increased similarly after both sessions, whilst leg vascular resistance decreased similarly after both sessions. Plasma nitrite increased only after the combined exercise. Malondialdehyde decreased after both sessions, and the decrease was greater after combined exercise. As a conclusion, a single session of combined exercise improves blood flow and leg vascular resistance similarly to walking session; however, combined exercise promoted better effects on oxidative stress.
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Hemodinâmica , Claudicação Intermitente/terapia , Extremidade Inferior/irrigação sanguínea , Estresse Oxidativo , Doença Arterial Periférica/terapia , Treinamento Resistido/métodos , Velocidade de Caminhada , Idoso , Índice Tornozelo-Braço , Biomarcadores/sangue , Pressão Sanguínea , Feminino , Humanos , Hiperemia/fisiopatologia , Claudicação Intermitente/sangue , Claudicação Intermitente/diagnóstico , Claudicação Intermitente/fisiopatologia , Masculino , Malondialdeído/sangue , Pessoa de Meia-Idade , Nitritos/sangue , Doença Arterial Periférica/sangue , Doença Arterial Periférica/diagnóstico , Doença Arterial Periférica/fisiopatologia , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Resistência VascularRESUMO
This study assessed the additive effects of passive heating and exercise on cardiac baroreflex sensitivity (cBRS) and heart rate variability (HRV). Twelve healthy young men (25 ± 1 yr, 23.8 ± 0.5 kg/m2) randomly underwent two experimental sessions: heat stress (HS; whole body heat stress using a tube-lined suit to increase core temperature by ~1°C) and normothermia (NT). Each session was composed of a preintervention rest (REST1); HS or NT interventions; postintervention rest (REST2); and 14 min of cycling exercise [7 min at 40%HRreserve (EX1) and 7 min at 60%HRreserve (EX2)]. Heart rate and finger blood pressure were continuously recorded. cBRS was assessed using the sequence (cBRSSEQ) and transfer function (cBRSTF) methods. HRV was assessed using the indexes standard deviation of RR intervals (SDNN) and root mean square of successive RR intervals (RMSSD). cBRS and HRV were not different between sessions during EX1 and EX2 (i.e., matched heart rate conditions: EX1 = 116 ± 3 vs. 114 ± 3 and EX2 = 143 ± 4 vs. 142 ± 3 beats/min but different workloads: EX1 = 50 ± 9 vs. 114 ± 8 and EX2 = 106 ± 10 vs. 165 ± 8 W; for HS and NT, respectively; P < 0.01). However, when comparing EX1 of NT with EX2 of HS (i.e., matched workload conditions but with different heart rates), cBRS and HRV were significantly reduced in HS (cBRSSEQ = 1.6 ± 0.3 vs. 0.6 ± 0.1 ms/mmHg, P < 0.01; SDNN = 2.3 ± 0.1 vs. 1.3 ± 0.2 ms, P < 0.01). In conclusion, in conditions matched by HR, the addition of heat stress to exercise does not affect cBRS and HRV. Alternatively, in workload-matched conditions, the addition of heat to exercise results in reduced cBRS and HRV compared with exercise in normothermia. NEW & NOTEWORTHY The present study assessed cardiac baroreflex sensitivity during the combination of heat and exercise stresses. This is the first study to show that prior whole body passive heating reduces cardiac baroreflex sensitivity and autonomic modulation of heart rate during exercise. These findings contribute to the better understanding of the role of thermoregulation on cardiovascular regulation during exercise.
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Barorreflexo , Exercício Físico , Frequência Cardíaca , Temperatura Alta , Adulto , Sistema Nervoso Autônomo , Pressão Sanguínea , Regulação da Temperatura Corporal , Humanos , Masculino , Estresse Fisiológico , Adulto JovemRESUMO
BACKGROUND: This study aimed at evaluating the after effects of a single bout of aerobic exercise on muscle sympathetic nerve activity (MSNA), peripheral vascular resistance and blood pressure (BP) in stages 2-3 chronic kidney disease (CKD) patients. We hypothesized that CKD patients present a greater decline in these variables after the exercise than healthy individuals. METHODS: Nine patients with stages 2-3 CKD (50 ± 8 years) and 12 healthy volunteers (50 ± 5 years) underwent 2 sessions, conducted in a random order: exercise (45 min, cycle ergometer, 50% of peak oxygen uptake) and rest (seated, 45 min). Sixty minutes after either intervention, MSNA (by microneurography), BP (by oscillometry), and forearm vascular resistance (FVR) were measured. A 2-way analysis of variance with group (between) and session (within) as main factors was employed, accepting p < 0.05 as significant. RESULTS: Diastolic BP and MSNA were higher in the CKD than the control group in both sessions. Responses after exercise were similar in both groups. Systolic BP, diastolic BP, MSNA and FVR were significantly lower after the exercise than after the rest session in both the CKD and the control groups (162 ± 15 vs. 152 ± 23 and 155 ± 11 vs. 145 ± 16 mm Hg, 91 ± 11 vs. 85 ± 14 and 77 ± 5 vs. 71 ± 10 mm Hg, 38 ± 4 vs. 31 ± 4 and 34 ± 2 vs. 27 ± 4 burst/min, 59 ± 29 vs. 41 ± 29 and 45 ± 20 vs. 31 ± 8 U, respectively, all p < 0.05). CONCLUSION: These results showed that aerobic exercise may produce hemodynamic and neural responses that can be beneficial to these patients in spite of CKD.
Assuntos
Pressão Sanguínea , Exercício Físico/fisiologia , Insuficiência Renal Crônica/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Resistência Vascular/fisiologia , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Post-exercise hypotension (PEH), calculated by the difference between post and pre-exercise values, it is greater after exercise performed in the evening than the morning. However, the hypotensive effect of morning exercise may be masked by the morning circadian increase in blood pressure. This study investigated PEH and its hemodynamic and autonomic mechanisms after sessions of aerobic exercise performed in the morning and evening, controlling for responses observed after control sessions performed at the same times of day. Sixteen pre-hypertensive men underwent four sessions (random order): two conducted in the morning (7:30 am) and two in the evening (5 pm). At each time of day, subjects underwent an exercise (cycling, 45 min, 50%VO2peak) and a control (sitting rest) session. Measurements were taken pre- and post-interventions in all the sessions. The net effects of exercise were calculated for each time of day by [(post-pre exercise)-(post-pre control)] and were compared by paired t-test (P<0.05). Exercise hypotensive net effects (e.g., decreasing systolic, diastolic and mean blood pressure) occurred at both times of day, but systolic blood pressure reductions were greater after morning exercise (-7±3 vs. -3±4 mmHg, P<0.05). Exercise decreased cardiac output only in the morning (-460±771 ml/min, P<0.05), while it decreased stroke volume similarly at both times of day and increased heart rate less in the morning than in the evening (+7±5 vs. +10±5 bpm, P<0.05). Only evening exercise increased sympathovagal balance (+1.5±1.6, P<0.05) and calf blood flow responses to reactive hyperemia (+120±179 vs. -70±188 U, P<0.05). In conclusion, PEH occurs after exercise conducted at both times of day, but the systolic hypotensive effect is greater after morning exercise when circadian variations are considered. This greater effect is accompanied by a reduction of cardiac output due to a smaller increase in heart rate and cardiac sympathovagal balance.
Assuntos
Exercício Físico/fisiologia , Hipotensão Pós-Exercício/fisiopatologia , Adulto , Sistema Nervoso Autônomo/fisiopatologia , Estudos Cross-Over , Hemodinâmica , Humanos , Masculino , Fluxo Sanguíneo Regional , Fatores de TempoRESUMO
No study has shown the effects of acute resistance exercise on vasodilatory capacity of patients with peripheral artery disease. The aim of this study was to analyse the effects of a single session of resistance exercise on blood flow, reactive hyperemia, plasma nitrite, and plasma malondialdehyde in patients with peripheral artery disease. Fourteen peripheral artery disease patients underwent, in a random order, 2 experimental sessions: control (rest for 30 min) and resistance exercise (8 exercises, 2 sets of 10 repetitions at an intensity of 5-7 in the OMNI Resistance Exercise Scale). Blood flow, reactive hyperemia, plasma nitrite, and malondialdehyde were measured before and 40 min after the interventions in both sessions. Data were compared between sessions by analysis of covariance, using pre-intervention values as covariates. The increases in blood flow, reactive hyperemia, and log plasma nitrite were greater (p ≤ 0.05) after resistance exercise than the control session (3.2 ± 0.1 vs. 2.7 ± 0.1 mL · 100 mL(-1) tissue · min(-1), 8.0 ± 0.1 vs. 5.7 ± 0.1 AU, and 1.36 ± 0.01 vs. 1.26 ± 0.01 µmol â L(-1), respectively). On the other hand, malondialdehyde was similar between sessions (p > 0.05). In peripheral arterial disease patients, a single session of resistance exercise increases blood flow and reactive hyperemia, which seems to be mediated, in part, by increases in nitric oxide release.