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1.
J Appl Physiol (1985) ; 136(4): 917-927, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38385178

RESUMO

Microneurographic recordings of muscle sympathetic nerve activity (MSNA) and the succeeding changes in beat-to-beat blood pressure (i.e., sympathetic transduction) provide important insights into the neural control of the circulation in humans. Despite its widespread use, the reliability of this technique remains unknown. Herein, we assessed the intra- and interday test-retest reliability of signal-averaging sympathetic transduction to blood pressure. Data were analyzed from 15 (9 M/6 F) young, healthy participants who completed two baseline recordings of fibular nerve MSNA separated by 60 min (intraday). The interday reliability was obtained in a subset of participants (n = 13, 9 M/4 F) who completed a follow-up MSNA study. Signal-averaging sympathetic transduction was quantified as peak change in diastolic (DBP) and mean arterial pressure (MAP) following a burst of MSNA. Analyses were also computed considering different MSNA burst sizes (quartiles of normalized MSNA) and burst patterns (singlets, couplets, triplets, and quadruplets+), as well as nonburst responses. Intraclass-correlation coefficients (ICCs) were used as the main reliability measure. Peak changes in MAP [intraday: ICC = 0.76 (0.30-0.92), P = 0.006; interday: ICC = 0.91 (0.63-0.97), P < 0.001] demonstrated very good to excellent reliability. Sympathetic transduction of MSNA burst size displayed moderate to very good reliability, though the reliability of MSNA burst pattern was poor to very good. Nonburst responses revealed poor intraday [ICC = 0.37 (-1.05 to 0.80), P = 0.21], but very good interday [ICC = 0.76 (0.18-0.93), P = 0.01] reliability. Intraday reliability measures were consistently lower than interday reliability. Similar results were obtained using DBP. Collectively, these findings provide evidence that the burst-triggering signal-averaging technique is a reliable measure of sympathetic transduction to blood pressure in young, healthy adults.NEW & NOTEWORTHY We found that signal-averaging sympathetic transduction to blood pressure displayed very good to excellent intra- and interday test-retest reliability in healthy, young adults. Reliability analyses according to muscle sympathetic burst size, burst pattern, and nonburst response were less consistent. Results were similar when using diastolic or mean arterial pressure in the transduction calculation. These findings suggest that the signal-averaging technique can be used with confidence to investigate sympathetic transduction to blood pressure in humans across time.


Assuntos
Músculo Esquelético , Sistema Nervoso Simpático , Adulto Jovem , Humanos , Pressão Sanguínea/fisiologia , Reprodutibilidade dos Testes , Músculo Esquelético/fisiologia , Sistema Nervoso Simpático/fisiologia , Frequência Cardíaca/fisiologia
2.
BMC Med Educ ; 24(1): 97, 2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38287390

RESUMO

BACKGROUND: Physiology is widely recognized as a difficult course, which can potentially increase students' withdrawal and failures rates. Several factors are likely contributing to the difficulties in learning physiology, including inherent features of the discipline as well as aspects related to instructions and/or students' perception. With regards to the later, it is currently unknown how students of exercise physiology think and explain physiology in terms of its cause or consequence (i.e., teleological or mechanistic thinking). Therefore, the aims of the present study were to determine 1) whether undergraduate students' perception of cardiorespiratory physiology during exercise follows a predominant teleological or mechanistic thinking, and 2) whether prior enrollment in physiology courses can influence the predominance of teleological vs. mechanistic thinking. METHODS: The test instrument was an online questionnaire about exercise physiology consisting of nine incomplete sentences about exercise physiology where students had to choose between a teleological or a mechanistic complement. The questionnaire was administered to undergraduate students in the following areas: 1) Movement Sciences (n = 152), 2) Health-related (n = 81) and, 3) Health-unrelated programs (n = 64). Students in Movement Sciences and Health-related programs were also analyzed separately in the following categories: 1) students who previously undertook physiology courses, and 2) students who did not take physiology courses. RESULTS: Overall, all groups presented a percentage of teleological thinking above 58%, which is considerably high. Teleological thinking was significantly higher in health-unrelated programs than health-related and movement sciences programs (76 ± 16% vs. 58 ± 26% vs. 61 ± 25%; P < 0.01). Further, students with prior enrollment in physiology classes presented a significantly lower percentage of teleological thinking than students without physiology classes (59 ± 25% vs. 72 ± 22%, respectively; P < 0.01), but the overall teleological reasoning remained predominant. CONCLUSIONS: These results confirm the hypothesis that undergraduate students tend to present teleological as opposed to mechanistic thinking in exercise physiology. Furthermore, although undergraduate students with prior enrollment in physiology classes presented significantly lower teleological thinking, it remained highly predominant suggesting that teleological thinking is partially independent of the degree of familiarity with this discipline.


Assuntos
Fisiologia , Estudantes , Humanos , Aprendizagem , Resolução de Problemas , Percepção , Fisiologia/educação
3.
J Appl Physiol (1985) ; 136(2): 385-398, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38174374

RESUMO

We investigated the locomotor muscle metaboreflex control of ventilation, circulation, and dyspnea in patients with chronic obstructive pulmonary disease (COPD). Ten patients [forced expiratory volume in 1 second (FEV1; means ± SD) = 43 ± 17% predicted] and nine age- and sex-matched controls underwent 1) cycling exercise followed by postexercise circulatory occlusion (PECO) to activate the metaboreflex or free circulatory flow to inactivate it, 2) cold pressor test to interpret whether any altered reflex response was specific to the metaboreflex arc, and 3) muscle biopsy to explore the metaboreflex arc afferent side. We measured airflow, dyspnea, heart rate, arterial pressure, muscle blood flow, and vascular conductance during reflexes activation. In addition, we measured fiber types, glutathione redox balance, and metaboreceptor-related mRNAs in the vastus lateralis. Metaboreflex activation increased ventilation versus free flow in patients (∼15%, P < 0.020) but not in controls (P > 0.450). In contrast, metaboreflex activation did not change dyspnea in patients (P = 1.000) but increased it in controls (∼100%, P < 0.001). Other metaboreflex-induced responses were similar between groups. Cold receptor activation increased ventilation similarly in both groups (P = 0.46). Patients had greater type II skeletal myocyte percentage (14%, P = 0.010), lower glutathione ratio (-34%, P = 0.015), and lower nerve growth factor (NGF) mRNA expression (-60%, P = 0.031) than controls. Therefore, COPD altered the locomotor muscle metaboreflex control of ventilation. It increased type II myocyte percentage and elicited redox imbalance, potentially producing more muscle metaboreceptor stimuli. Moreover, it decreased NGF expression, suggesting a downregulation of metabolically sensitive muscle afferents.NEW & NOTEWORTHY This study's integrative physiology approach provides evidence for a specific alteration in locomotor muscle metaboreflex control of ventilation in patients with COPD. Furthermore, molecular analyses of a skeletal muscle biopsy suggest that the amount of muscle metaboreceptor stimuli derived from type II skeletal myocytes and redox imbalance overcame a downregulation of metabolically sensitive muscle afferents.


Assuntos
Fator de Crescimento Neural , Doença Pulmonar Obstrutiva Crônica , Humanos , Fator de Crescimento Neural/metabolismo , Reflexo/fisiologia , Músculo Esquelético/fisiologia , Dispneia , Glutationa/metabolismo , Pressão Sanguínea/fisiologia
4.
Rev. bras. ciênc. esporte ; 45: e20230015, 2023. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1514981

RESUMO

ABSTRACT Scopus and Web of Science were used to evaluate papers on Physical Education worldwide and in Brazil. Most documents are published in the USA and England, Brazil being the 6th largest. Brazilians tend to publish in Brazil. Countries with a higher % of documents in Q1 journals have higher % of top 10% cited documents. Most countries increase their Top 10% score when publishing in open access, while Brazil decreases. Differentiation between country clusters is due to % documents in Q1 journals, international collaboration, Open Access, citations/paper and documents in Top 10%. Brazil researches similar topics to those worldwide. Publishing in Q1 journals, and more industry and international collaboration can increase the impact of publications by Brazilian authors.


RESUMO Scopus e Web of Science foram usados ​​para avaliar artigos sobre Educação Física no mundo e no Brasil. A maioria dos documentos é publicada nos EUA e na Inglaterra, sendo o Brasil o 6º maior. Brasileiros tendem a publicar no Brasil. Os países com maior % de documentos em periódicos do 1º quartil têm maior % dos citados. A maioria dos países aumenta seu impacto publicando em acesso aberto, enquanto o Brasil diminui. A diferença entre países deve-se à % de documentos em periódicos do 1º quartil, colaboração internacional, acesso aberto, citações/artigos e documentos no Top 10%. O Brasil pesquisa temas semelhantes aos do mundo. A publicação em periódicos do 1º quartil, mais colaboração industrial e internacional podem aumentar o impacto das publicações de autores brasileiros.


RESUMEN Scopus y Web of Science se utilizaron para evaluar artículos sobre Educación Física en el mundo y Brasil. La mayoría de los documentos se publican en EEUU e Inglaterra, siendo Brasil el sexto más grande. Los brasileños tienden a publicar en Brasil. Los países con un % más alto de documentos en revistas Q1 tienen un % más alto citados en el 10% superior, y publican en acceso abierto, mientras que Brasil disminuye. La diferenciación entre países se debe a % de documentos en revistas Q1, colaboración internacional, acceso abierto, citas/artículo y documentos en el 10% superior. Brasil investiga temas similares a los del mundo. La publicación en revistas Q1, una mayor colaboración internacional y de la industria pueden aumentar el impacto de las publicaciones de autores brasileños.

6.
Clin Auton Res ; 32(4): 271-290, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35727398

RESUMO

The exercise pressor reflex is a feedback mechanism engaged upon stimulation of mechano- and metabosensitive skeletal muscle afferents. Activation of these afferents elicits a reflex increase in heart rate, blood pressure, and ventilation in an intensity-dependent manner. Consequently, the exercise pressor reflex has been postulated to be one of the principal mediators of the cardiorespiratory responses to exercise. In this updated review, we will discuss classical and recent advancements in our understating of the exercise pressor reflex function in both human and animal models. Particular attention will be paid to the afferent mechanisms and pathways involved during its activation, its effects on different target organs, its potential role in the abnormal cardiovascular response to exercise in diseased states, and the impact of age and biological sex on these responses. Finally, we will highlight some unanswered questions in the literature that may inspire future investigations in the field.


Assuntos
Sistema Cardiovascular , Reflexo , Animais , Pressão Sanguínea/fisiologia , Exercício Físico/fisiologia , Humanos , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Reflexo/fisiologia
7.
J Clin Hypertens (Greenwich) ; 24(6): 704-712, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35582956

RESUMO

Although it has been suggested that increased arterial stiffness is linked to exaggerated blood pressure (BP) from brief moderate exercise, it is not clear whether this occurs in older adults with and without hypertension. This study investigates whether the immediate post-exercise systolic BP following brief moderate exercise is associated with arterial stiffness in older females with different BP status. This cross-sectional study included 191 older females aged 60-80 years without known cardiovascular disease (CVD). Arterial stiffness was determined by aortic pulse wave velocity (aPWV). Systolic BP was measured before and immediately following a 3-min moderate walking test (stage 1 Bruce protocol). Specific quartile-based thresholds were used to define an exaggerated immediate post-exercise systolic BP for hypertensive and normotensive older females (quartile 4 as an exaggerated response). Traditional CVD risk factors were assessed (covariates). Older females from the highest quartile of immediate post-exercise absolute systolic BP showed higher aPWV compared to their peers from the lowest quartile (ß = .22 m/s, p = .018). The quartile-based threshold to define the exaggerated post-exercise systolic BP was higher in hypertensive than in normotensive older females (174 vs. 172 mmHg). In summary, exaggerated immediate post-exercise systolic BP following a brief moderate exercise is associated with higher arterial stiffness in older females with different BP status.


Assuntos
Doenças Cardiovasculares , Hipertensão , Rigidez Vascular , Idoso , Pressão Sanguínea/fisiologia , Doenças Cardiovasculares/epidemiologia , Estudos Transversais , Feminino , Humanos , Hipertensão/diagnóstico , Hipertensão/epidemiologia , Análise de Onda de Pulso , Rigidez Vascular/fisiologia
8.
Front Cardiovasc Med ; 9: 853427, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35360028

RESUMO

Previously, we demonstrated that acute transcranial direct current stimulation (tDCS) reduced blood pressure (BP) and improved autonomic modulation in hypertensives. We hypothesized that acute and short-term tDCS intervention can promote similar benefits in resistant hypertensive patients (RHT). We assessed the impact of one (acute intervention) and ten (short-term intervention) tDCS or SHAM (20 min, each) sessions on BP, pulse interval (PI) and systolic blood pressure variabilities, humoral mechanisms associated with BP regulation, and cytokines levels. True RHT subjects (n = 13) were randomly submitted to one and ten SHAM and tDCS crossing sessions (1 week of "washout"). Hemodynamic (Finometer®, Beatscope), office BP, and autonomic variables (accessed through spectral analysis of the pulse-to-pulse BP signal, in the time and frequency domain - Fast Fourrier Transform) were measured at baseline and after the short-term intervention. 24 h-ambulatory BP monitoring was measured after acute and short-term protocols. Acute intervention: tDCS reduced BP, cardiac output, and increase high-frequency band of PI (vagal modulation to the heart). Short-term protocol: tDCS did not change BP and cardiac output parameters. In contrast, central systolic BP (-12%), augmentation index (-31%), and pulse wave velocity (34%) were decreased by the short-term tDCS when compared to SHAM. These positive results were accompanied by a reduction in the low-frequency band (-37%) and an increase of the high-frequency band of PI (+62%) compared to SHAM. These findings collectively indicate that short-term tDCS concomitantly improves resting cardiac autonomic control and pulse wave behavior and reduces central BP in RHT patients, https://ensaiosclinicos.gov.br/rg/RBR-8n7c9p.

10.
Ann Vasc Surg ; 77: 31-37, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34455045

RESUMO

BACKGROUND: The mechanisms underlying functional impairments in symptomatic PAD patients are controversial and poorly understood. Endothelial dysfunction and arterial stiffness have been proposed as potential mechanisms related to functional impairment in symptomatic PAD patients, however, more studies are needed to confirm these associations. OBJECTIVE: To analyze the association between vascular function and walking impairment in patients with peripheral arterial disease (PAD) and symptoms of claudication. METHODS: This was a cross-sectional study that included 68 patients with symptomatic PAD. All patients underwent an objective (Six-minute walk test [6MWT], 4-meter walk test) and a subjective (Walking Impairment Questionnaire [WIQ]) measurement of walking impairment. Vascular parameters measured were pulse-wave velocity (PWV) and flow-mediated dilation (FMD). Multiple linear regression was performed to investigate the association among walking impairment variables with vascular function parameters. RESULTS: No significant associations between the claudication onset distance (PWV: b=.060, P = 0.842; FMD: b=-.192, P = 0.456), 6MWT (PWV: b=.007, P = 0..975; FMD: b=.090, P = 0.725), WIQ distance (PWV: b=.337, P = 0.117; FMD: b=-.025, P = 0.895) WIQ speed (PWV: b=.320, P = 0.181; FMD: b=-.028, P = 0.497), WIQ stairs (PWV: b=.256, P = 0.204; FMD: b=-.228, P = 0.230), 4-meter usual walk (PWV: b=-.421, P = 0.107; FMD: b=-.338, P = 0.112), 4-meter fast walk (PWV: b=-.496, P = 0.063; FMD: b=-.371, P = 0.086) and vascular function were found. CONCLUSIONS: In symptomatic PAD patients, vascular function is not associated to walking impairment, even when adjusting for comorbid conditions and diabetes.


Assuntos
Endotélio Vascular/fisiopatologia , Claudicação Intermitente/fisiopatologia , Doença Arterial Periférica/fisiopatologia , Rigidez Vascular , Vasodilatação , Caminhada , Idoso , Comorbidade , Estudos Transversais , Tolerância ao Exercício , Feminino , Humanos , Claudicação Intermitente/diagnóstico , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/diagnóstico , Valor Preditivo dos Testes , Análise de Onda de Pulso , Inquéritos e Questionários , Teste de Caminhada
11.
J Vasc Res ; 58(6): 388-391, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34186532

RESUMO

BACKGROUND: Isometric handgrip training (IHT) promotes vascular adaptations in different populations. AIMS: We assessed the sex differences in vascular adaptations of IHT in a sample of older adults with symptomatic peripheral artery disease (PAD). METHODS: Fifty-three older patients with symptomatic PAD (6 women and 13 men in IHT and 13 women and 21 men in the control group) participated in this study. The IHT group performed 3 sessions per week, for 8 weeks, consisting of 4 sets of isometric contractions for 2 min at 30% of maximum voluntary contraction and a 4-min interval between sets. The control group received a compression ball in order to minimize the placebo effects, representing sham training. Blood flow and brachial flow-mediated dilation were analyzed at before and after 8 weeks of intervention. We compared the responses (Δ = post-pre values) of each group (women control, women IHT, men control, and men IHT) with a Kruskal-Wallis test. RESULTS: There were no differences in all groups after 8 weeks of IHT in Δ brachial diameter (p = 0.850), Δ flow-mediated dilation (p = 0.241), Δ time to peak diameter (p = 0.528), and Δ FMD/AUC (p = 0.397). CONCLUSIONS: There are no effects of sex on vascular adaptation after 8 weeks of IHT in older adults with symptomatic PAD.


Assuntos
Artéria Braquial/fisiopatologia , Terapia por Exercício , Força da Mão , Contração Isométrica , Doença Arterial Periférica/terapia , Vasodilatação , Adaptação Fisiológica , Fatores Etários , Idoso , Brasil , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/diagnóstico , Doença Arterial Periférica/fisiopatologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Fluxo Sanguíneo Regional , Estudos Retrospectivos , Fatores Sexuais , Fatores de Tempo , Resultado do Tratamento
12.
Front Physiol ; 12: 626640, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33815139

RESUMO

Parkinson's disease (PD) is a common neurodegenerative disorder classically characterized by symptoms of motor impairment (e.g., tremor and rigidity), but also presenting with important non-motor impairments. There is evidence for the reduced activity of both the parasympathetic and sympathetic limbs of the autonomic nervous system at rest in PD. Moreover, inappropriate autonomic adjustments accompany exercise, which can lead to inadequate hemodynamic responses, the failure to match the metabolic demands of working skeletal muscle and exercise intolerance. The underlying mechanisms remain unclear, but relevant alterations in several discrete central regions (e.g., dorsal motor nucleus of the vagus nerve, intermediolateral cell column) have been identified. Herein, we critically evaluate the clinically significant and complex associations between the autonomic dysfunction, fatigue and exercise capacity in PD.

13.
Int J Sports Med ; 42(11): 985-993, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33618392

RESUMO

We investigated the acute effects of isometric biceps exercise on resting and ambulatory blood pressure in hypertensive adults. A total of 12 medicated hypertensive adults (aged 47±7 years; body mass index 27.2±2.7 kg/m2; resting blood pressure 123±12/74±6 mmHg) performed an isometric biceps exercise session (bilateral biceps exercise; 4×1 min at 30% of 1-RM, 2 min recovery) and a control session (without exercise) in a randomized order separated by a 7 to 10-day period. Resting blood pressure, heart rate, and heart rate variability indexes (SDNN, RMSSD, LF, HF, and LF/HF) were measured pre- and up to 30 min post-sessions. Next, ambulatory blood pressure was monitored during 22-hour post-sessions (awake and asleep periods). No significant changes were observed for resting blood pressure, heart rate, or heart rate variability indexes up to 30 min post-sessions (p>0.05). Furthermore, no significant differences were observed in average ambulatory blood pressure values in 22-hour (126±11/71±6 mmHg vs. 126±15/71±9 mmHg), awake (127±10/74±6 mmHg vs. 130±14/75±10 mmHg), and asleep (123±15/68±6 mmHg vs. 120±17/66±9 mmHg) periods between the control and isometric sessions, respectively (p>0.05). In conclusion, an isometric biceps exercise session does not elicit an acute antihypertensive effect in adults with hypertension, which suggests that its prescription to improve the acute BP control is limited.


Assuntos
Pressão Sanguínea , Exercício Físico/fisiologia , Hipertensão , Músculo Esquelético/fisiologia , Adulto , Monitorização Ambulatorial da Pressão Arterial , Estudos Cross-Over , Terapia por Exercício , Feminino , Frequência Cardíaca , Humanos , Contração Isométrica , Masculino , Pessoa de Meia-Idade
14.
J Neurophysiol ; 125(4): 1425-1439, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33625931

RESUMO

The incidence of Parkinson's disease (PD) is increasing worldwide. Although the PD hallmark is the motor impairments, nonmotor dysfunctions are now becoming more recognized. Recently, studies have suggested that baroreflex dysfunction is one of the underlying mechanisms of cardiovascular dysregulation observed in patients with PD. However, the large body of literature on baroreflex function in PD is unclear. The baroreflex system plays a major role in the autonomic, and ultimately blood pressure and heart rate, adjustments that accompany acute cardiovascular stressors on a daily basis. Therefore, impaired baroreflex function (i.e., decreased sensitivity or gain) can lead to altered neural cardiovascular responses. Since PD affects parasympathetic and sympathetic branches of the autonomic nervous system and both are orchestrated by the baroreflex system, understanding of this crucial mechanism in PD is necessary. In the present review, we summarize the potential altered central and peripheral mechanisms affecting the feedback-controlled loops that comprise the reflex arc in patients with PD. Major factors including arterial stiffness, reduced number of C1 and activation of non-C1 neurons, presence of central α-synuclein aggregation, cardiac sympathetic denervation, attenuated muscle sympathetic nerve activity, and lower norepinephrine release could compromise baroreflex function in PD. Results from patients with PD and from animal models of PD provide the reader with a clearer picture of baroreflex function in this clinical condition. By doing so, our intent is to stimulate future studies to evaluate several unanswered questions in this research area.


Assuntos
Barorreflexo/fisiologia , Pressão Sanguínea/fisiologia , Bulbo/fisiopatologia , Doença de Parkinson/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Animais , Humanos , Bulbo/metabolismo , Bulbo/patologia
17.
J Neurophysiol ; 124(4): 1144-1151, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32877297

RESUMO

Nonmotor symptoms are common in Parkinson's disease (PD) and they include dysregulation of cardiovascular system, which adversely affects quality of life. Recent studies provide indirect evidence that baroreflex dysfunction may be one of the mechanisms of cardiovascular dysregulation in PD. Herein, we tested the hypothesis that the baroreflex gain, assessed across an extensive range of the reflex arc by eliciting rapid changes in blood pressure (BP) induced by sequential boluses of vasoactive drugs (modified-Oxford technique) would be attenuated in middle-aged patients with PD. Beat-to-beat heart rate (electrocardiography) and BP (finger photoplethysmography) were obtained during 10 min of supine rest preceding the modified-Oxford (bolus of nitroprusside followed by phenylephrine 1 min afterward) in 11 patients with PD (51 ± 6 yr) and 7 age-matched controls (47 ± 6 yr). The resulting systolic BP and R-R interval responses were plotted and fitted with segmental linear regression and symmetric sigmoid model. Spontaneous indices obtained via sequence technique were also used to estimate baroreflex gain. Compared with controls, the estimated gains measured by segmental linear regression (patients: 3.83 ± 2.6 ms/mmHg versus controls: 7.78 ± 1.7 ms/mmHg; P = 0.003) and symmetric sigmoid model (patients: 12.36 ± 6.9 ms/mmHg versus controls: 32.02 ± 19.0 ms/mmHg; P = 0.009) were lower in patients with PD. The operating range of BP was larger in patients with PD compared with controls (13 ± 7 mmHg versus controls: 7 ± 3 mmHg; P = 0.032). Of note, the gain obtained from spontaneous indices was similar between groups. These data indicate that baroreflex gain was reduced by >50% in PD, thereby providing clear and direct evidence that cardiovagal baroreflex dysfunction occurs in PD.NEW & NOTEWORTHY Attenuated baroreflex gain may contribute to adverse cardiovascular outcomes, including orthostatic intolerance symptoms typically observed in patients with Parkinson's disease. We found that the baroreflex gain (assessed by the modified-Oxford technique) is attenuated and accompanied by an increased operating range in patients with Parkinson's disease. These findings highlight that cardiovascular perturbations are required to detect baroreflex impairments and that spontaneous indices do not reveal cardiovagal-baroreflex dysfunction in a middle-aged group of patients with Parkinson's disease.


Assuntos
Barorreflexo , Doença de Parkinson/fisiopatologia , Pressão Sanguínea/efeitos dos fármacos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nitroprussiato/farmacologia , Fenilefrina/farmacologia , Vasoconstritores/farmacologia , Vasodilatadores/farmacologia
18.
Auton Neurosci ; 228: 102714, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32829151

RESUMO

A parasympathetic reactivation is an underlying mechanism mediating the rapid fall in heart rate (HR) at the onset of post-exercise ischemia (PEI) in humans. Herein, we tested the hypothesis that, compared to men, women present a slower HR recovery at the cessation of isometric handgrip exercise (i.e., onset of PEI) due to an attenuated cardiac vagal reactivation. Forty-seven (23 women) young and healthy volunteers were recruited. Subjects performed 90s of isometric handgrip exercise at 40% of maximal voluntary contraction followed by 3-min of PEI. The onset of PEI was analyzed over the first 30s in 10s windows. Cardiac vagal reactivation was indexed using the HR fall and by HR variability metrics (e.g., RMSSD and SDNN) immediately after the cessation of the exercise. HR was significantly increased from rest during exercise in men and women and increases were similar between sexes. However, following the cessation of exercise, the HR recovery was significantly slower in women compared to men regardless of the time point (women vs. men: ∆-14 ± 8 vs. ∆-18 ± 6 beats.min-1 at 10s; ∆-20 ± 9 vs. ∆-25 ± 8 beats.min-1 at 20s; ∆-22 ± 10 vs. ∆-27 ± 9 beats.min-1 at 30s; P = .027). RMSSD and SDNN increased at the cessation of exercise in greater magnitude in men compared to women. These findings demonstrate that women had a slower HR recovery at the cessation of isometric handgrip exercise and onset of PEI compared to men, suggesting a sex-related difference in cardiac vagal reactivation in healthy young humans.


Assuntos
Sistema Nervoso Autônomo/fisiologia , Exercício Físico/fisiologia , Mãos/fisiologia , Frequência Cardíaca/fisiologia , Músculo Esquelético/fisiologia , Reflexo/fisiologia , Caracteres Sexuais , Adulto , Feminino , Humanos , Masculino , Músculo Esquelético/metabolismo , Adulto Jovem
19.
SAGE Open Med ; 8: 2050312120921603, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32435491

RESUMO

The incidence of Parkinson's disease is increasing worldwide. The motor dysfunctions are the hallmark of the disease, but patients also experience non-motor impairments, and over 40% of the patients experience coexistent abnormalities, such as orthostatic hypotension. Exercise training has been suggested as a coping resource to alleviate Parkinson's disease symptoms and delay disease progression. However, the body of knowledge is showing that the cardiovascular response to exercise in patients with Parkinson's disease is altered. Adequate cardiovascular and hemodynamic adjustments to exercise are necessary to meet the metabolic demands of working skeletal muscle properly. Therefore, since Parkinson's disease affects parasympathetic and sympathetic branches of the autonomic nervous system and the latter are crucial in ensuring these adjustments are adequately made, the understanding of these responses during exercise in this population is necessary. Several neural control mechanisms are responsible for the autonomic changes in the cardiovascular and hemodynamic systems seen during exercise. In this sense, the purpose of the present work is to review the current knowledge regarding the cardiovascular responses to dynamic and isometric/resistance exercise as well as the mechanisms by which the body maintains appropriate perfusion pressure to all organs during exercise in patients with Parkinson's disease. Results from patients with Parkinson's disease and animal models of Parkinson's disease provide the reader with a well-rounded knowledge base. Through this, we will highlight what is known and not known about how the neural control of circulation is responding during exercise and the adaptations that occur when individuals exercise regularly.

20.
Exp Brain Res ; 238(5): 1265-1276, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32303809

RESUMO

Remote limb ischemic preconditioning (RIPC) has shown to improve dynamic postural control in humans. However, studies on the underlying adaptations of spinal cord networks have never been performed. The present work addresses this issue by investigating parameters from the soleus H-reflex recruitment curve (RC), presynaptic mechanisms of reflex modulation (presynaptic inhibition-PSI, and post activation depression-PAD), and the excursion of the center of pressure (CP) recorded during 1 min in upright stance over a compliant surface. A sham ischemic protocol (partial obstruction of blood flow) was applied to the contralateral thigh along four consecutive days. The same procedure was repeated with full obstruction (RIPC) three days after ending the sham protocol. Data were collected before and after both sham and RIPC protocols. The follow-up data were collected five days after the last ischemic intervention. Significant reduction was detected for both the fast oscillations of the CP (higher frequency components) and the parameter estimated from the RC corresponding to the high amplitude H-reflexes (p < 0.05). Even though the magnitude of effects was similar, it was washed out within three days after sham, but persisted for at least five days after RIPC. No significant differences were found for PSI and PAD levels across conditions. These findings indicate that RIPC leads to enduring changes in spinal cord excitability for the latest reflexively recruited motoneurons, along with improvement in balance control. However, these adaptations were not mediated by the presynaptic mechanisms currently assessed.


Assuntos
Adaptação Fisiológica/fisiologia , Fenômenos Eletrofisiológicos/fisiologia , Reflexo H/fisiologia , Precondicionamento Isquêmico , Extremidade Inferior/fisiologia , Músculo Esquelético/fisiologia , Equilíbrio Postural/fisiologia , Medula Espinal/fisiologia , Adulto , Eletromiografia , Humanos , Masculino , Adulto Jovem
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