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Autonomic nervous system (ANS) activity causes acute variations in blood pressure (BP) and heart rate (HR). These systems are challenged during high intensity interval exercise (HIIE). However, BP variability (BPV) and HR variability (HRV) response to HIIE is unknown. We characterized BPV and HRV during an acute HIIE bout using spectral low frequency [LF] and high frequency [HF] domains. We hypothesized that BPV would increase and HRV would decrease during high-intensity and active-recovery of HIIE compared to baseline [BL] and BPV would reduce and HRV would increase during cool down, post-HIIE, and 30 min post-HIIE compared to BL. HIIE involved 10 min of alternating high-intensity and active-recovery (approximately 70% and 10% of Wattmax) on a recumbent stepper. We did a secondary analysis on 23 datasets. The participants were 25 ± 1.5 years, 48% females. Our results showed high-intensity BPV LF was not significantly different from BL while HF increased. HRV LF and HF decreased compared to BL. During active-recovery, LF and HF for BPV and HRV increased greater than high-intensity. HRV LF and HF returned to BL after 30 min of recovery, whereas BPV HF was higher compared to BL. The rapid switching during HIIE uniquely modulates cardiovascular and ANS.
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Sistema Nervoso Autônomo , Pressão Sanguínea , Frequência Cardíaca , Humanos , Frequência Cardíaca/fisiologia , Feminino , Masculino , Pressão Sanguínea/fisiologia , Adulto , Sistema Nervoso Autônomo/fisiologia , Treinamento Intervalado de Alta Intensidade/métodos , Exercício Físico/fisiologia , Adulto JovemRESUMO
Background: Obstructive sleep apnea (OSA) negatively impacts post-stroke recovery. This study's purpose: examine the prevalence of undiagnosed OSA and describe a simple tool to identify those at-risk for OSA in the early phase of stroke recovery. Methods: This was a cross-sectional descriptive study of people â¼15 days post-stroke. Adults with stroke diagnosis admitted to inpatient rehabilitation over a 3-year period were included if they were alert/arousable, able to consent/assent to participation, and excluded if they had a pre-existing OSA diagnosis, other neurologic health conditions, recent craniectomy, global aphasia, inability to ambulate 150 feet independently pre-stroke, pregnant, or inability to understand English. OSA was deemed present if oxygen desaturation index (ODI) of >=15 resulted from overnight oximetry measures. Prevalence of OSA was determined accordingly. Four participant characteristics comprised the "BASH" tool (body mass index >=35, age>=50, sex=male, hypertension=yes). A receiver operator characteristics (ROC) curve analysis was performed with BASH as test variable and OSA presence as state variable. Results: Participants (n=123) were 50.4% male, averaged 64.12 years old (sd 14.08), and self-identified race as 75.6% White, 20.3% Black/African American, 2.4%>1 race, and 1.6% other; 22% had OSA. ROC analysis indicated BASH score >=3 predicts presence of OSA (sensitivity=0.778, specificity=0.656, area under the curve =0.746, p<0.001). Conclusions: Prevalence of undiagnosed OSA in the early stroke recovery phase is high. With detection of OSA post-stroke, it may be possible to offset untreated OSA's deleterious impact on post-stroke recovery of function. The BASH tool is an effective OSA screener for this application.
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BACKGROUND AND PURPOSE: Studies investigating high-intensity interval exercise (HIIE) in stroke typically emphasize treadmill training. However, a literature review suggested that seated devices such as a recumbent stepper or cycle offer a promising alternative for HIIE since exercise can be prescribed using peak power output (PPO). Therefore, this would give health care professionals the ability to monitor and adapt power output for the target heart rate range. The purpose of this secondary analysis was to examine the feasibility of prescribing short-interval, low-volume HIIE using PPO in chronic stroke. METHODS: We used several methods to test feasibility: (1)Acceptability: Measured by the percentage of participants who completed the entire HIIE protocol; (2) Implementation was assessed by the number of reported cardiac or serious adverse events during submaximal exercise testing and HIIE and the average percentage of participants reaching vigorous intensity, defined by the American College of Sports Medicine as at least 77% of age-predicted maximal heart rate (HR max ). RESULTS: Data were available for 28 participants who were 32.2 (17.2) months post-stroke and 61.4 (11.9) years of age. Twenty-eight participants completed HIIE per protocol. No cardiac or serious adverse events occurred during the submaximal exercise test or during HIIE. The rapid switching between HIIE and recovery showed no evidence of blood pressure reaching unsafe thresholds. Average intensity during HIIE reached 76.8% HR max , which is slightly below the target of 77.0%. DISCUSSION AND CONCLUSIONS: A single bout of short-interval, low-volume HIIE, prescribed using PPO, was feasible in chronic stroke.Video Abstract : Available for more insights from the authors (Supplemental Digital Content, Video, available at: http://links.lww.com/JNPT/A474 ).
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Peripheral vascular dysfunction, measured as flow-mediated dilation (FMD), is present across all phases of stroke recovery and elevates the risk for recurrent cardiovascular events. The objective of this systematic review and meta-analysis was to characterize baseline FMD in individuals' poststroke, with consideration for each phase of stroke recovery. Three databases (PubMed, CINAHL, and Embase) were searched between January 1, 2000 and October 12, 2023 for studies that examined baseline FMD in stroke. Three reviewers conducted abstract and full-text screening, data extraction, and quality assessment. A random effects model was used to estimate FMD across studies. Meta-regression was used to examine the impact of age and time since stroke (acute, subacute, chronic) on FMD. Twenty-eight studies with ischemic and hemorrhagic stroke were included. Descriptive statistics for the demographics and FMD values of each study are presented. For the meta-analysis, average estimate FMD was 3.9% (95% CI: 2.5-5.3%). We report a large amount of heterogeneity (Cochrane's Q P value <0.001, and I2 = 99.6%). Differences in average age and the time poststroke between studies were not significantly associated with differences in FMD values. Despite the large heterogeneity for FMD values across studies, our primary finding suggests that FMD remains impaired across all phases of stroke.NEW & NOTEWORTHY This systematic review and meta-analysis offers invaluable insight into poststroke vascular function. Despite the inherent heterogeneity among the 28 studies analyzed, we report that peripheral vascular dysfunction, as quantified by flow-mediated dilation, exists across all stages of stroke recovery. This finding underscores the importance for interventions that focus on improving vascular health and secondary stroke prevention.
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Acidente Vascular Cerebral , Vasodilatação , Humanos , Endotélio Vascular/fisiopatologia , Acidente Vascular Cerebral/fisiopatologia , Vasodilatação/fisiologiaRESUMO
Fluctuating arterial blood pressure during high-intensity interval exercise (HIIE) may challenge dynamic cerebral autoregulation (dCA), specifically after stroke after an injury to the cerebrovasculature. We hypothesized that dCA would be attenuated at rest and during a sit-to-stand transition immediately after and 30 min after HIIE in individuals poststroke compared with age- and sex-matched control subjects (CON). HIIE switched every minute between 70% and 10% estimated maximal watts for 10 min. Mean arterial pressure (MAP) and middle cerebral artery blood velocity (MCAv) were recorded. dCA was quantified during spontaneous fluctuations in MAP and MCAv via transfer function analysis. For sit-to-stand, time delay before an increase in cerebrovascular conductance index (CVCi = MCAv/MAP), rate of regulation, and % change in MCAv and MAP were measured. Twenty-two individuals poststroke (age 60 ± 12 yr, 31 ± 16 mo) and twenty-four CON (age 60 ± 13 yr) completed the study. Very low frequency (VLF) gain (P = 0.02, η2 = 0.18) and normalized gain (P = 0.01, η2 = 0.43) had a group × time interaction, with CON improving after HIIE whereas individuals poststroke did not. Individuals poststroke had lower VLF phase (P = 0.03, η2 = 0.22) after HIIE compared with CON. We found no differences in the sit-to-stand measurement of dCA. Our study showed lower dCA during spontaneous fluctuations in MCAv and MAP following HIIE in individuals poststroke compared with CON, whereas the sit-to-stand response was maintained.NEW & NOTEWORTHY This study provides novel insights into poststroke dynamic cerebral autoregulation (dCA) following an acute bout of high-intensity interval exercise (HIIE). In people after stroke, dCA appears attenuated during spontaneous fluctuations in mean arterial pressure (MAP) and middle cerebral artery blood velocity (MCAv) following HIIE. However, the dCA response during a single sit-to-stand transition after HIIE showed no significant difference from controls. These findings suggest that HIIE may temporarily challenge dCA after exercise in individuals with stroke.
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Exercício Físico , Acidente Vascular Cerebral , Adulto , Humanos , Pessoa de Meia-Idade , Idoso , Exercício Físico/fisiologia , Pressão Arterial , Homeostase/fisiologia , Artéria Cerebral Média/fisiologia , Circulação Cerebrovascular/fisiologia , Pressão Sanguínea/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologiaRESUMO
Autonomic nervous system (ANS) activity causes acute variations in the blood pressure. Blood pressure responds to high intensity interval exercise (HIIE) repeatedly during alternating intensities, however, ANS response to the changing intensities of HIIE is unknown. We characterized the response of beat-to-beat blood pressure variability (BTB BPV) to an acute bout of HIIE using coefficient of variation (CoV) and spectral low frequency [LF], and high frequency [HF] domains. Our hypotheses were mean arterial pressure BTB BPV, would increase during 1) high intensity and 2) active recovery of HIIE compared to baseline (BL). BTB BPV would reduce during 1) cool down 2) post HIIE 3) 30 minutes post HIIE compared to BL in young adults. HIIE included bouts of 1-minute high-intensity separated by 1-minute recovery (â¡70% and 10% estimated Wattmax) for total of 10 minutes on a recumbent stepper. A secondary analysis was performed using twenty-one datasets of young individuals (age 25±1.5, 48% female). During high intensity, LF and HF increased compared to BL (p < 0.05) indicating increased sympathetic activity and breathing. During active recovery, LF and HF remained elevated above BL and were greater than during high intensity (p ≤ 0.02). Sympathetic activity reduced back to BL immediately post HIIE but returned to being higher than BL at 30 minutes after HIIE (p=0.001). BTB BPV CoV also increased during HIIE compared to BL (p<0.05). Results suggest that young healthy individuals have increased BTB BPV during HIIE suggesting cardiovascular system responds to ANS fluctuations during changing exercise intensity. New and Noteworthy: This novel study analyzed beat -to-beat blood pressure variability during high intensity interval exercise (HIIE) in young healthy adults. We found that blood pressure variability was highest during active recovery compared to resting or high intensity exercise. Moreover, variability increased during HIIE but returned to resting post-exercise. These findings provide valuable insights into the blood pressure and ANS responses to HIIE, contributing to our understanding of their impact on overall cardiovascular health in young adults.
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RATIONALE: Fatigue affects almost half of all people living with stroke. Stroke survivors rank understanding fatigue and how to reduce it as one of the highest research priorities. METHODS: We convened an interdisciplinary, international group of clinical and pre-clinical researchers and lived experience experts. We identified four priority areas: (1) best measurement tools for research, (2) clinical identification of fatigue and potentially modifiable causes, (3) promising interventions and recommendations for future trials, and (4) possible biological mechanisms of fatigue. Cross-cutting themes were aphasia and the voice of people with lived experience. Working parties were formed and structured consensus building processes were followed. RESULTS: We present 20 recommendations covering outcome measures for research, development, and testing of new interventions and priority areas for future research on the biology of post-stroke fatigue. We developed and recommend the use of the Stroke Fatigue Clinical Assessment Tool. CONCLUSIONS: By synthesizing current knowledge in post-stroke fatigue across clinical and pre-clinical fields, our work provides a roadmap for future research into post-stroke fatigue.
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Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Humanos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/terapia , Consenso , Pesquisa de Reabilitação , Fadiga/etiologia , Fadiga/terapiaRESUMO
RATIONALE: Fatigue affects almost half of all people living with stroke. Stroke survivors rank understanding fatigue and how to reduce it as one of the highest research priorities. METHODS: We convened an interdisciplinary, international group of clinical and pre-clinical researchers and lived experience experts. We identified four priority areas: (1) best measurement tools for research, (2) clinical identification of fatigue and potentially modifiable causes, (3) promising interventions and recommendations for future trials, and (4) possible biological mechanisms of fatigue. Cross-cutting themes were aphasia and the voice of people with lived experience. Working parties were formed and structured consensus building processes were followed. RESULTS: We present 20 recommendations covering outcome measures for research, development, and testing of new interventions and priority areas for future research on the biology of post-stroke fatigue. We developed and recommend the use of the Stroke Fatigue Clinical Assessment Tool. CONCLUSIONS: By synthesizing current knowledge in post-stroke fatigue across clinical and pre-clinical fields, our work provides a roadmap for future research into post-stroke fatigue.
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Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Humanos , Consenso , Acidente Vascular Cerebral/complicações , Pesquisa de Reabilitação , Fadiga/etiologia , Fadiga/terapiaRESUMO
BACKGROUND AND PURPOSE: Aerobic exercise can elicit positive effects on neuroplasticity and cognitive executive function but is poorly understood after stroke. We tested the effect of 4 weeks of aerobic exercise training on inhibitory and facilitatory elements of cognitive executive function and electroencephalography markers of cortical inhibition and facilitation. We investigated relationships between stimulus-evoked cortical responses, blood lactate levels during training, and aerobic fitness postintervention. METHODS: Twelve individuals with chronic (>6 months) stroke completed an aerobic exercise intervention (40 minutes, 3×/wk). Electroencephalography and motor response times were assessed during congruent (response facilitation) and incongruent (response inhibition) stimuli of a Flanker task. Aerobic fitness capacity was assessed as o2peak during a treadmill test pre- and postintervention. Blood lactate was assessed acutely (<1 minute) after exercise each week. Cortical inhibition (N2) and facilitation (frontal P3) were quantified as peak amplitudes and latencies of stimulus-evoked electroencephalographic activity over the frontal cortical region. RESULTS: Following exercise training, the response inhibition speed increased while response facilitation remained unchanged. A relationship between earlier cortical N2 response and faster response inhibition emerged postintervention. Individuals who produced higher lactate during exercise training achieved faster response inhibition and tended to show earlier cortical N2 responses postintervention. There were no associations between o2peak and metrics of behavioral or neurophysiologic function. DISCUSSION AND CONCLUSIONS: These preliminary findings provide novel evidence for selective benefits of aerobic exercise on inhibitory control during the initial 4-week period after initiation of exercise training and implicate a potential therapeutic effect of lactate on poststroke inhibitory control.
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Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Humanos , Terapia por Exercício , Exercício Físico/fisiologia , LactatosRESUMO
BACKGROUND: There is evidence that aerobic exercise is beneficial for brain health, but these effects are variable between individuals and the underlying mechanisms that modulate these benefits remain unclear. OBJECTIVE: We sought to characterize the acute physiological response of bioenergetic and neurotrophic blood biomarkers to exercise in cognitively healthy older adults, as well as relationships with brain blood flow. METHODS: We measured exercise-induced changes in lactate, which has been linked to brain blood flow, as well brain-derived neurotrophic factor (BDNF), a neurotrophin related to brain health. We further quantified changes in brain blood flow using arterial spin labeling. RESULTS: As expected, lactate and BDNF both changed with time post exercise. Intriguingly, there was a negative relationship between lactate response (area under the curve) and brain blood flow measured acutely following exercise. Finally, the BDNF response tracked strongly with change in platelet activation, providing evidence that platelet activation is an important mechanism for trophic-related exercise responses. CONCLUSIONS: Lactate and BDNF respond acutely to exercise, and the lactate response tracks with changes in brain blood flow. Further investigation into how these factors relate to brain health-related outcomes in exercise trials is warranted.
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Fator Neurotrófico Derivado do Encéfalo , Exercício Físico , Humanos , Idoso , Exercício Físico/fisiologia , Ácido Láctico , Circulação Cerebrovascular , BiomarcadoresRESUMO
BACKGROUND: Post-stroke fatigue (PSF) is a significant and highly prevalent symptom, whose mechanisms are poorly understood. The third Stroke Recovery and Rehabilitation Roundtable paper on PSF focussed primarily on defining and measuring PSF while mechanisms were briefly discussed. This companion paper to the main paper is aimed at elaborating possible mechanisms of PSF. METHODS: This paper reviews the available evidence that potentially explains the pathophysiology of PSF and draws parallels from fatigue literature in other conditions. We start by proposing a case for phenotyping PSF based on structural, functional, and behavioral characteristics of PSF. This is followed by discussion of a potentially significant role of early inflammation in the development of fatigue, specifically the impact of low-grade inflammation and its long-term systemic effects resulting in PSF. Of the many neurotransmitter systems in the brain, the dopaminergic systems have the most evidence for a role in PSF, along with a role in sensorimotor processing. Sensorimotor neural network dynamics are compromised as highlighted by evidence from both neurostimulation and neuromodulation studies. The double-edged sword effect of exercise on PSF provides further insight into how PSF might emerge and the importance of carefully titrating interventional paradigms. CONCLUSION: The paper concludes by synthesizing the presented evidence into a unifying model of fatigue which distinguishes between factors that pre-dispose, precipitate, and perpetuate PSF. This framework will help guide new research into the biological mechanisms of PSF which is a necessary prerequisite for developing treatments to mitigate the debilitating effects of post-stroke fatigue.
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Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Humanos , Seguimentos , Depressão/diagnóstico , Acidente Vascular Cerebral/complicações , Inflamação , FadigaRESUMO
BACKGROUND: Androgen deprivation therapy (ADT) for prostate cancer is associated with cardiovascular comorbidities and numerous adverse effects decreasing health-related quality of life. Both exercise and dietary interventions have shown promise in reducing ADT-related negative sequelae. However, feasibility for personalized combined exercise/nutrition/education interventions is not well established. OBJECTIVE: The purpose of this randomized, controlled, mixed-methods pilot study was to evaluate the feasibility of a nurse-led, telephone-delivered education, exercise, and nutrition intervention, Staying Strong & Healthy, to minimize ADT-related cardiovascular/metabolic risks and symptoms. METHODS: Staying Strong & Healthy involves individually tailored education, exercise (aerobic and resistance), and nutrition intervention delivered over 6 months and was compared with attention control. The primary quantitative outcome measure was change from baseline in low-density lipoprotein. Secondary outcomes included change in lipid levels (total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides), fasting blood glucose, hemoglobin A 1c , health-related quality of life, and diet quality. Assessments were performed at baseline, 6 months, and 12 months. RESULTS: Feasibility was demonstrated by low attrition rates and high participant satisfaction. No between-group differences were demonstrated in the cardiovascular/metabolic outcomes. Significant within-group improvements were noted for high-density lipoprotein and hemoglobin A 1c in the intervention group. CONCLUSION: The study results indicate that participation in a personalized, nurse-delivered exercise, nutrition, and educational intervention is feasible and acceptable to men with prostate cancer receiving ADT. IMPLICATIONS FOR PRACTICE: Future randomized controlled research powered to detect significant differences is needed to confirm the impact of the Staying Strong & Healthy intervention on reduction of the cardiovascular/metabolic impact of ADT for men with prostate cancer.
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Neoplasias da Próstata , Qualidade de Vida , Masculino , Humanos , Antagonistas de Androgênios/efeitos adversos , Androgênios , Projetos Piloto , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/complicações , Terapia por Exercício/métodos , Lipoproteínas HDL , Lipoproteínas LDLRESUMO
High-intensity interval training (HIIE) may present unique challenges to the cerebrovascular system in individuals post-stroke. We hypothesized lower middle cerebral artery blood velocity (MCAv) in individuals post-stroke: 1) during 10 minutes of HIIE, 2) immediately following HIIE, and 3) 30 minutes after HIIE, compared to age- and sex-matched controls (CON). We used a recumbent stepper submaximal exercise test to determine workloads for high-intensity and active recovery. Our low volume HIIE protocol consisted of 1-minute intervals for 10 minutes. During HIIE, we measured MCAv, mean arterial pressure (MAP), heart rate (HR), and end tidal carbon dioxide (PETCO2). We assessed carotid-femoral pulse wave velocity as a measure of arterial stiffness. Fifty participants completed the study (25 post-stroke, 76% ischemic, 32% moderate disability). Individuals post-stroke had lower MCAv during HIIE compared to CON (p = 0.03), which remained 30 minutes after HIIE. Individuals post-stroke had greater arterial stiffness (p = 0.01) which was moderately associated with a smaller MCAv responsiveness during HIIE (r = -0.44). No differences were found for MAP, HR, and PETCO2. This study suggests individuals post-stroke had a lower MCAv during HIIE compared to their peers, which remained during recovery up to 30 minutes. Arterial stiffness may contribute to the lower cerebrovascular responsiveness post-stroke.
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Calcineurin inhibitors are inherent vasoconstrictors. Cerebral vasoconstriction can reduce cerebral blood flow (CBF), and negatively impact cerebrovascular response (CVR) to exercise, and cognitive function. The once-daily extended-release (LCP) tacrolimus has fewer side effects than the immediate-release (IR) tacrolimus. The role of calcineurin inhibitors on CBF and the impact of specific formulations of tacrolimus on CBF, CVR, and cognitive function are unknown. In this pilot study, we evaluated whether changing from IR tacrolimus to LCP tacrolimus modulates CBF, CVR, or cognitive function in kidney transplant (KT) recipients. Methods: We randomized (2:1) 30 stable KT recipients on IR tacrolimus to intervention (switch to LCP tacrolimus) and control (continue IR tacrolimus) arms. We measured CBF, CVR, and cognitive function at baseline and at 12 wk. We used ANCOVA to evaluate changes in outcome variables, with baseline values and study arm as covariates. We used descriptive statistics with mean changes in outcome variables to compare the 2 groups. Results: Participants were 51 ± 13 y old. There was no difference in plasma tacrolimus levels at baseline and at 12 wk in the 2 arms. The changes in CBF, resting middle cerebral artery velocity, CVR, and cognitive function were more favorable in the intervention arm than in the control group. Conclusions: Changing IR tacrolimus to LCP tacrolimus may improve CBF, cerebrovascular dynamics, and cognitive function in KT recipients. Larger studies are needed to confirm these results.
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Current methods estimate the time delay (TD) before the onset of dynamic cerebral autoregulation (dCA) from verbal command to stand. A force sensor used during a sit-to-stand dCA measure provides an objective moment an individual stands (arise-and-off, AO). We hypothesized that the detection of AO would improve the accuracy of TD compared with estimation. We measured middle cerebral artery blood velocity (MCAv) and mean arterial pressure (MAP) for 60 s sitting followed by 2-min standing, three times separated by 20 min. TD was calculated as the time from: (1) verbal command and (2) AO, until an increase in cerebrovascular conductance index (CVCi = MCAv/MAP). Sixty-five participants were enrolled: young adults (n = 25), older adults (n = 20), and individuals post-stroke (n = 20). The TD calculated from AO ( x ¯ $$ \overline{x} $$ = 2.98 ± 1.64 s) was shorter than TD estimated from verbal command ( x ¯ $$ \overline{x} $$ = 3.35 ± 1.72 s, η2 = 0.49, p < 0.001), improving measurement error by ~17%. TD measurement error was not related to age or stroke. Therefore, the force sensor provided an objective method to improve the calculation of TD compared with current methods. Our data support using a force sensor during sit-to-stand dCA measures in adults across the lifespan and post-stroke.
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Artéria Cerebral Média , Acidente Vascular Cerebral , Adulto Jovem , Humanos , Idoso , Homeostase , Postura Sentada , Posição OrtostáticaRESUMO
Background: Locomotor high-intensity interval training (HIIT) has been shown to improve walking capacity more than moderate-intensity aerobic training (MAT) after stroke, but it is unclear which training parameter(s) should be prioritized (e.g. speed, heart rate, blood lactate, step count) and to what extent walking capacity gains are the result of neuromotor versus cardiorespiratory adaptations. Objective: Assess which training parameters and longitudinal adaptations most strongly mediate 6-minute walk distance (6MWD) gains from post-stroke HIIT. Methods: The HIT-Stroke Trial randomized 55 persons with chronic stroke and persistent walking limitations to HIIT or MAT and collected detailed training data. Blinded outcomes included 6MWD, plus measures of neuromotor gait function (e.g. fastest 10-meter gait speed) and aerobic capacity (e.g. ventilatory threshold). This ancillary analysis used structural equation models to compare mediating effects of different training parameters and longitudinal adaptations on 6MWD. Results: Net gains in 6MWD from HIIT versus MAT were primarily mediated by faster training speeds and longitudinal adaptations in neuromotor gait function. Training step count was also positively associated with 6MWD gains, but was lower with HIIT versus MAT, which decreased the net 6MWD gain. HIIT generated higher training heart rate and lactate than MAT, but aerobic capacity gains were similar between groups, and 6MWD changes were not associated with training heart rate, training lactate, or aerobic adaptations. Conclusions: To increase walking capacity with post-stroke HIIT, training speed and step count appear to be the most important parameters to prioritize.
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Objective: To identify sleep patterns and their association with recovery after stroke during inpatient rehabilitation, and to determine if clinical outcomes are different between participants demonstrating abnormal sleep patterns as compared to those with normal sleep patterns. Methods: Cohort study in which participants were undergoing inpatient rehabilitation after a stroke. Sleep quantity and quality was measured using an actigraph that participants wore for up to 7 nights during the first week of inpatient rehabilitation. Medicare Quality Indicators (GG code), Barthel Index, gait speed, and Berg balance scale were collected at admission and discharge. Participants were categorized into groups based on meeting or not meeting recommended sleep quantity and quality guidelines. Association between sleep patterns and outcomes were assessed using Pearson correlation and differences in outcomes and length of stay between participants who met or did not meet sleep quantity and quality guidelines were determined using independent sample t-test. Results: 69 participants were in the study. Sleep quantity and quality was poor for all the participants. None of the participants met all the sleep quantity and quality guidelines. There were moderate to small associations (-0.42 to 0.22) between some sleep quantity and quality parameters and clinical outcomes. Participants who's sleep efficiency (SE) was <85% had a significantly longer length of stay compared to those who's SE was >=85% (17.4 vs. 21.5 days, p<0.05). Conclusions: People with stroke undergoing inpatient rehabilitation have poor sleep quantity and quality. There is a small to moderate association between sleep patterns and clinical outcomes and participants with poor sleep quality had longer length of stay compared to those with good sleep quality. Further research is necessary to better understand the complex relationship between sleep and recovery after stroke. Impact: Sleep is associated with functional recovery during inpatient rehabilitation after stroke.
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Importance: For walking rehabilitation after stroke, training intensity and duration are critical dosing parameters that lack optimization. Objective: To assess the optimal training intensity (vigorous vs moderate) and minimum training duration (4, 8, or 12 weeks) needed to maximize immediate improvement in walking capacity in patients with chronic stroke. Design, Setting, and Participants: This multicenter randomized clinical trial using an intent-to-treat analysis was conducted from January 2019 to April 2022 at rehabilitation and exercise research laboratories. Survivors of a single stroke who were aged 40 to 80 years and had persistent walking limitations 6 months or more after the stroke were enrolled. Interventions: Participants were randomized 1:1 to high-intensity interval training (HIIT) or moderate-intensity aerobic training (MAT), each involving 45 minutes of walking practice 3 times per week for 12 weeks. The HIIT protocol used repeated 30-second bursts of walking at maximum safe speed, alternated with 30- to 60-second rest periods, targeting a mean aerobic intensity above 60% of the heart rate reserve (HRR). The MAT protocol used continuous walking with speed adjusted to maintain an initial target of 40% of the HRR, progressing up to 60% of the HRR as tolerated. Main Outcomes and Measures: The main outcome was 6-minute walk test distance. Outcomes were assessed by blinded raters after 4, 8, and 12 weeks of training. Results: Of 55 participants (mean [SD] age, 63 [10] years; 36 male [65.5%]), 27 were randomized to HIIT and 28 to MAT. The mean (SD) time since stroke was 2.5 (1.3) years, and mean (SD) 6-minute walk test distance at baseline was 239 (132) m. Participants attended 1675 of 1980 planned treatment visits (84.6%) and 197 of 220 planned testing visits (89.5%). No serious adverse events related to study procedures occurred. Groups had similar 6-minute walk test distance changes after 4 weeks (HIIT, 27 m [95% CI, 6-48 m]; MAT, 12 m [95% CI, -9 to 33 m]; mean difference, 15 m [95% CI, -13 to 42 m]; P = .28), but HIIT elicited greater gains after 8 weeks (58 m [95% CI, 39-76 m] vs 29 m [95% CI, 9-48 m]; mean difference, 29 m [95% CI, 5-54 m]; P = .02) and 12 weeks (71 m [95% CI, 49-94 m] vs 27 m [95% CI, 3-50 m]; mean difference, 44 m [95% CI, 14-74 m]; P = .005) of training; HIIT also showed greater improvements than MAT on some secondary measures of gait speed and fatigue. Conclusions and Relevance: These findings show proof of concept that vigorous training intensity is a critical dosing parameter for walking rehabilitation. In patients with chronic stroke, vigorous walking exercise produced significant and meaningful gains in walking capacity with only 4 weeks of training, but at least 12 weeks were needed to maximize immediate gains. Trial Registration: ClinicalTrials.gov Identifier: NCT03760016.
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Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Humanos , Masculino , Pessoa de Meia-Idade , Reabilitação do Acidente Vascular Cerebral/métodos , Terapia por Exercício/métodos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/fisiopatologia , Caminhada/fisiologia , Exercício FísicoRESUMO
PURPOSE: To investigate whether mixed circuit training (MCT) elicits the recommended exercise intensity and energy expenditure in people after stroke, and to establish the between-day reproducibility for the percentages of heart rate reserve (%HRR), oxygen uptake reserve (%VO2R), and energy expenditure elicited during two bouts of MCT. METHODS: Seven people aged 58 (12) yr, who previously had a stroke, performed a cardiopulmonary exercise test, a non-exercise control session, and two bouts of MCT. The MCT included 3 circuits of 10 resistance exercises at 15-repetition maximum intensity, with each set of resistance exercise interspersed with 45-s of walking. Expired gases were collected during the MCT and control session and for 40 min afterward. Control session was necessary to calculate the net energy expenditure associated with each bout of MCT. RESULTS: Mean %VO2R (1st MCT: 51.1%, P = .037; 2nd MCT: 54.0%, P = .009) and %HRR (1st MCT: 66.4%, P = .007; 2nd MCT: 67.9%, P = .010) exceeded the recommended minimum intensity of 40%. Both %VO2R (P = .586 and 0.987, respectively) and %HRR (P = .681 and 0.237, respectively) during the 1st and 2nd bouts of MCT were not significantly different to their corresponding gas exchange threshold values derived from cardiopulmonary exercise testing. Mean net total energy expenditure significantly exceeded the minimum recommend energy expenditure in the 1st (P = .048) and 2nd (P = .023) bouts of MCT. Between-day reproducibility for %HRR, %VO2R, and energy expenditure was excellent (ICC: 0.92-0.97). CONCLUSIONS: MCT elicited physiological strain recommended for improving health-related fitness in people after stroke and these responses demonstrated excellent between-day reproducibility.