Physio‐markers based on predictive models of cerebral hemodynamics yield accurate diagnosis of cognitive impairment and differentiate MCI from AD.

Background: A multi‐center study in Los Angeles (USC), Kansas City (KUMC) and Dallas (UT‐SWMC) quantified via predictive modeling the dynamics of cerebral perfusion regulation (CO2 vasoreactivity and cerebral autoregulation) in MCI/AD patients and cognitively normal controls under resting conditions. The goal was to develop model‐based physio‐markers for accurate diagnosis of MCI and pre‐clinical AD, motivated by our previous findings of significant impairment of cerebral perfusion regulation in MCI and mild AD patients.

Method: Continuous spontaneous changes in arterial blood pressure, end‐tidal CO2, cerebral blood flow velocity in middle cerebral arteries and cortical tissue oxygenation at lateral prefrontal cortex were recorded over two 6‐8 min sessions, separated by session of slow‐paced breathing (6 breaths/minute), in 53 MCI (28 APOE4 non‐carriers and 25 APOE4 carriers), 33 mild AD patients (13 APOE4 non‐carriers and 20 APOE4 carriers) and 74 age/sex‐matched cognitively normal controls (50 APOE4 non‐carriers and 24 APOE4 carriers).

A simple measure of voluntary control of breathing is an effective physio‐marker for differentiating MCI from mild AD patients and MCI/AD patients from cognitively normal controls.

Background: Control of breathing is known to be adversely affected by cognitive impairment, often associated with sleep apnea or disordered breathing during sleep in MCI/AD. The origin of this disorder is thought to be in the dysfunction of the respiratory control centers of the brainstem or in the impaired afferent signaling from cortical regions. Continuous breathing data were collected in a multi‐center study in Los Angeles (USC), Kansas City (KUMC) and Dallas (UT‐SWMC), and used to compute respiratory rate variability (RRV) to test the hypothesis that voluntary control of breathing is impaired in MCI and mild AD patients relative to cognitively normal controls, and whether this impairment is more severe in mild AD than MCI patients.

The relationship between submaximal measures of cardiorespiratory fitness, brain structure, and cognition in older adults.

Background: Cardiorespiratory fitness (CRF) has been repeatedly linked to healthy brain and cognitive outcomes in aging. Treadmill‐based graded maximal exercise testing (GXT) is a common technique for measuring CRF in exercise studies. Because it is often challenging for older adults to reach the commonly accepted criterion measure of oxygen consumption, alternate, submaximal measures have been explored.

APOE4 carriers display loss of anticipatory cerebral vascular regulation over AD progression.

Introduction: Maintenance of cerebral blood flow during orthostasis is impaired with aging and associated with cognitive decline, but the effect of Apolipoprotein 4-allele () is unknown.

Methods: Older adults (n=108) ( carriers, n=47; noncarriers, n=61) diagnosed as cognitively-normal (NC), MCI, or AD participated. Middle cerebral artery blood velocity (MCAv), assessed using Transcranial Doppler ultrasound, and beat-to-beat mean arterial blood pressure (MAP) were continuously recorded during a sit-to-stand transition.

Predicting Walking Capacity Outcomes After Moderate to High Intensity Locomotor Training in Chronic Stroke.

Purpose: Moderate-to-high intensity locomotor training (M-HIT) is strongly recommended in stroke rehabilitation but outcomes are variable. This study aimed to identify baseline clinical characteristics that predict change in walking capacity following M-HIT in chronic stroke.

Methods: This analysis used data from the HIT-Stroke Trial (N=55), which involved up to 36 sessions of either moderate or high intensity locomotor training.

Blood pressure and heart rate variability to assess autonomic response to an acute bout of high intensity interval exercise in healthy young adults.

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.

Prevalence and Detection of Obstructive Sleep Apnea Early after Stroke.

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 ∼15 days post-stroke.

Dual-task balance control reveals cerebrovascular-behavioral relationships in older adults resistant to cognitive decline.

Introduction:: Age-related decline in cerebrovascular function is linked to cognitive dysfunction. Cognitive dual-task interference in balance control is well-known clinically and is emerging as a key risk factor for dementia and falls. Links between cerebral blood flow, white matter hyperintensities, and dual-task performance have been found under pathologic conditions (e.

Feasibility of a Recumbent Stepper for Short-Interval, Low-Volume High-Intensity Interval Exercise in Stroke.

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.

Peripheral vascular function in stroke: systematic review and meta-analysis.

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.

Lower dynamic cerebral autoregulation following acute bout of low-volume high-intensity interval exercise in chronic stroke compared to healthy adults.

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.

Blood Pressure Variability and Autonomic Response to an Acute Bout of High Intensity Interval Exercise in Healthy Young Adults.

Unlabelled: 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.

Financial Cost Analysis Associated with a Locomotor Exercise Randomized Controlled Trial in Chronic Stroke.

Background: Post-stroke recovery trials pose distinct recruitment and retention challenges, and understanding the financial requirements of conducting randomized controlled trials is crucial to ensure sufficient resources for successful study execution. The purpose of this analysis was to quantify the costs at a single site with a large catchment area of the Moderate-Intensity Exercise Versus High-Intensity Interval Training to Recover Walking Post-Stroke, HIT Stroke Trial.

Methods: To determine cost, study expense reports were gathered and divided into four categories: oversight, recruitment, retention, and outcome assessments.

Biomarker Responses to Acute Exercise and Relationship with Brain Blood Flow.

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.

A roadmap for research in post-stroke fatigue: Consensus-based core recommendations from the third Stroke Recovery and Rehabilitation Roundtable.

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.

Lower middle cerebral artery blood velocity during low-volume high-intensity interval exercise in chronic stroke.

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.

The Association of Tacrolimus Formulation on Cerebral Blood Flow and Cognitive Function.

Unlabelled: 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.

Aerobic Exercise Improves Cortical Inhibitory Function After Stroke: A Preliminary Investigation.

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.

A roadmap for research in post-stroke fatigue: Consensus-based core recommendations from the third Stroke Recovery and Rehabilitation Roundtable.

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.

Force sensor reduced measurement error compared with verbal command during sit-to-stand assessment of cerebral autoregulation.

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.

Training parameters and longitudinal adaptations that most strongly mediate walking capacity gains from high-intensity interval training post-stroke.

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.

Optimal Intensity and Duration of Walking Rehabilitation in Patients With Chronic Stroke: A Randomized Clinical Trial.

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.

Can mixed circuit training elicit the recommended exercise intensity and energy expenditure in people after stroke?

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 (%VOR), 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.

Proceedings from the Albert Charitable Trust Inaugural Workshop on 'Understanding the Acute Effects of Exercise on the Brain'.

An inaugural workshop supported by "The Leo and Anne Albert Charitable Trust," was held October 4-7, 2019 in Scottsdale, Arizona, to focus on the effects of exercise on the brain and to discuss how physical activity may prevent or delay the onset of aging-related neurodegenerative conditions. The Scientific Program Committee (led by Dr. Jeff Burns) assembled translational, clinical, and basic scientists who research various aspects of the effects of exercise on the body and brain, with the overall goal of gaining a better understanding as to how to delay or prevent neurodegenerative diseases.

Hippocampal blood flow rapidly and preferentially increases after a bout of moderate-intensity exercise in older adults with poor cerebrovascular health.

Over the course of aging, there is an early degradation of cerebrovascular health, which may be attenuated with aerobic exercise training. Yet, the acute cerebrovascular response to a single bout of exercise remains elusive, particularly within key brain regions most affected by age-related disease processes. We investigated the acute global and region-specific cerebral blood flow (CBF) response to 15 minutes of moderate-intensity aerobic exercise in older adults (≥65 years; n = 60) using arterial spin labeling magnetic resonance imaging.