Increased serum brain-derived neurotrophic factor with high-intensity interval training in stroke patients: A randomized controlled trial

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. 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.

Influence of High-Intensity Interval Training on Neuroplasticity Markers in Post-Stroke Patients: Systematic Review

Background: Exercise has shown beneficial effects on neuronal neuroplasticity; therefore, we want to analyze the influence of high-intensity interval training (HIIT) on neuroplasticity markers in post-stroke patients. Methods: A systematic review of RCTs including studies with stroke participants was conducted using the following databases (PubMed, LILACS, ProQuest, PEDro, Web of Science). Searches lasted till (20/11/2023). Studies that used a HIIT protocol as the main treatment or as a coadjutant treatment whose outcomes were neural plasticity markers were used and compared with other exercise protocols, controls or other kinds of treatment. Studies that included other neurological illnesses, comorbidities that interfere with stroke or patients unable to complete a HIIT protocol were excluded. HIIT protocol, methods to assess intensity, neuroplasticity markers (plasmatic and neurophysiological) and other types of assessments such as cognitive scales were extracted to make a narrative synthesis. Jadad and PEDro scales were used to assess bias. Results: Eight articles were included, one included lacunar stroke (less than 3 weeks) and the rest had chronic stroke. The results found here indicate that HIIT facilitates neuronal recovery in response to an ischemic injury. This type of training increases the plasma concentrations of lactate, BDNF and VEGF, which are neurotrophic and growth factors involved in neuroplasticity. HIIT also positively regulates other neurophysiological measurements that are directly associated with a better outcome in motor learning tasks. Conclusions: We conclude that HIIT improves post-stroke recovery by increasing neuroplasticity markers. However, a limited number of studies have been found indicating that future studies are needed that assess this effect and include the analysis of the number of intervals and their duration in order to maximize this effect.

Aerobic exercise interventions for promoting cardiovascular health and mobility after stroke: a systematic review with Bayesian network meta-analysis

OBJECTIVE

To determine the superiority of aerobic exercise (AE) interventions on key outcomes of stroke recovery, including cardiorespiratory fitness (V̇O2peak, primary outcome), systolic blood pressure (SBP) and mobility (6 min Walk Test (6MWT) distance and 10 m Usual Gait Speed) after stroke.

DATA SOURCES

MEDLINE, EMBASE, Web of Science, CINAHL, CENTRAL, SPORTDiscus, PsycINFO and AMED Allied and Complementary Medicine were searched from inception to February 2023.

ELIGIBILITY CRITERIA

Randomised controlled trials were included that compared the effects of any AE interventions (low-intensity, moderate-intensity, high-intensity continuous training (HICT), high-intensity interval training (HIIT)) to no exercise, usual care or other AE interventions in individuals poststroke.

ANALYSES

Systematic review with Bayesian network meta-analysis (NMA) methodology was employed. Surface under the cumulative ranking curve (SUCRA) values were used to rank interventions. The Grading of Recommendations, Assessment, Development and Evaluation minimally contextualised framework for NMA was followed.

RESULTS

There were 28 studies (n=1298) included in the NMA for V̇O2peak, 11 (n=648) for SBP, 28 (n=1494) for 6MWT and 18 (n=775) for the 10 m Usual Gait Speed. The greatest effect on V̇O2peak, 6MWT and 10 m Usual Gait Speed was observed after HIIT and HICT. No differences between interventions were found for SBP. SUCRA values identified HIIT as the superior AE intervention for all outcomes of interest. HIIT was the most effective intervention for improving V̇O2peak (2.9 mL/kg/min (95% credible interval 0.8 to 5.0) moderate certainty) compared with usual care.

CONCLUSION

This NMA suggests that higher-intensity AE is superior to traditional low-intensity to moderate-intensity AE for improving outcomes after stroke.

The effect of moderate and vigorous aerobic exercise training on the cognitive and walking ability among stroke patients during different periods: A systematic review and meta-analysis

OBJECTIVE

The study examined whether rehabilitation using aerobic exercise is more appropriate for patients less than 3 months post-stroke or more appropriate for patients more than 3 months post-stroke.

METHOD

PubMed, Embase, Web of Science, Scopus and CNKI databases were searched from inception to September 2023. All studies included must be written in English and grey literature was excluded. The quality of the study was evaluated using the PEDro scale. Standard mean difference (SMD) and 95% confidence interval (CI) were calculated. The primary outcomes are cognitive ability and walking ability. The intervention of the experimental group must be or include high-intensity aerobic training or moderate-intensity aerobic training. In addition, we required low intensity routine exercises in control group.

RESULT

Only 15 studies were included in this meta-analysis. The results showed that aerobic exercise has a positive rehabilitation effect on cognitive and walking ability of stroke patients. Global Cognitive Function (SMD = 0.81 95%CI 0.49-1.12), Walking Capacity (SMD = 1.19, 95%CI 0.75-1.62), VO2peak (SMD = 0.97, 95%CI 0.66-1.28), and brain-derived neurotrophic factor (SMD = 2.73, 95%CI 2.03-3.43). We further observed that patients who suffered a stroke within the past three months exhibited superior rehabilitation outcomes compared to patients who suffered a stroke more than three months ago, specifically in terms of cognitive ability, walking tests, and cardiopulmonary function.

CONCLUSIONS

It is recommended to carry out treatment for patients in the initial stage of stroke, and it is required to pay attention to exercise intensity in the process of treatment to ensure patient safety.

Measuring Neuroplasticity in Response to Cardiovascular Exercise in People With Stroke: A Critical Perspective

BACKGROUND

Rehabilitative treatments that promote neuroplasticity are believed to improve recovery after stroke. Animal studies have shown that cardiovascular exercise (CE) promotes neuroplasticity but the effects of this intervention on the human brain and its implications for the functional recovery of patients remain unclear. The use of biomarkers has enabled the assessment of cellular and molecular events that occur in the central nervous system after brain injury. Some of these biomarkers have proven to be particularly valuable for the diagnosis of severity, prognosis of recovery, as well as for measuring the neuroplastic response to different treatments after stroke.

OBJECTIVES

To provide a critical analysis on the current evidence supporting the use of neurophysiological, neuroimaging, and blood biomarkers to assess the neuroplastic response to CE in individuals poststroke.

RESULTS

Most biomarkers used are responsive to the effects of acute and chronic CE interventions, but the response appears to be variable and is not consistently associated with functional improvements. Small sample sizes, methodological variability, incomplete information regarding patient's characteristics, inadequate standardization of training parameters, and lack of reporting of associations with functional outcomes preclude the quantification of the neuroplastic effects of CE poststroke using biomarkers.

CONCLUSION

Consensus on the optimal biomarkers to monitor the neuroplastic response to CE is currently lacking. By addressing critical methodological issues, future studies could advance our understanding of the use of biomarkers to measure the impact of CE on neuroplasticity and functional recovery in patients with stroke.

Comparative efficacy of different exercise methods to improve cardiopulmonary function in stroke patients: a network meta-analysis of randomized controlled trials

Background

Although some studies have shown that exercise has a good effect on improving the cardiopulmonary function of stroke patients, it still needs to be determined which exercise method does this more effectively. We, therefore, aimed to evaluate the effectiveness of different exercise methods in improving cardiovascular function in stroke patients through a network meta-analysis (NMA), providing a basis to select the best treatment plan for stroke patients.

Methods

We systematically searched CNKI, WanFang, VIP, CBM, PubMed, Embase, Web of Science, and The Cochrane Library databases from establishment to 30 April 2023. Randomized controlled trials (RCTS) on exercise improving cardiopulmonary function in stroke patients were included, and we screened the included articles and extracted the relevant data. RevMan (version 5.4) and Stata (version 17.0) were used for data analysis.

Results

We included 35 RCTs and a total of 2,008 subjects. Intervention measures included high-intensity interval training (HIIT), aerobic training (AT), resistance training (RT), combined aerobic and resistance exercise (CE), and conventional therapy (CT). In the network meta-analysis, the surface under the cumulative ranking area (SUCRA) ranking result indicated that HIIT improved peak oxygen uptake (VO2peak) and 6 mins walking distance (6MWD) optimally, with rankings of HIIT (100.0%) > CE (70.5%) > AT (50.2%) > RT (27.7%) > CT (1.6%), and HIIT (90.9%) > RT (60.6%) > AT (48.9%) > RT (48.1%) > CT (1.5%), respectively. The SUCRA ranking result showed that CE improved systolic blood pressure (SBP) and diastolic blood pressure (DBP) optimally, with rankings of CE (82.1%) > HIIT (49.8%) > AT (35.3%) > CT (32.8%), and CE (86.7%) > AT (45.0%) > HIIT (39.5%) > CT (28.8%), respectively.

Conclusion

We showed that exercise can effectively improve the cardiopulmonary function of stroke patients. HIIT was the most effective in improving VO2peak and 6MWD in stroke patients. CE was the most effective in improving SBP and DBP in stroke patients. However, due to the limitations of existing clinical studies and evidence, larger sample size, multi-center, and high-quality RCTs are needed to verify the above conclusions in the future.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier [CRD42023436773].

Home-based high-intensity interval training for people with Parkinson's: Protocol for the HIIT-Home4Parkinson's randomized, controlled feasibility study

Background

High-intensity interval training (HIIT) is feasible and beneficial for some people with Parkinson's (PwP), although adherence to extended programs may be problematic. PwP face barriers to exercise such as lack of time, expense, and difficulty with travel logistics due to motor symptoms. HIIT based in the home setting if practical, could therefore be apposite for PwP by overcoming these barriers. However, until now, no home-based HIIT program for PwP has been developed. Cocreated by PwP, clinicians, and family members, the HIIT-Home4Parkinson's (HH4P) program is an innovative, 12-week home-based HIIT program for PwP. This protocol describes a feasibility study designed to assess the feasibility and safety of the HH4P program, explore outcomes that may be sensitive to change, and inform the implementation of a potential full trial.

Methods/design

Using a randomized controlled parallel group design, 24 independently mobile people with Parkinson's of mild to moderate disease severity will be randomized 1:1 to either the HH4P program plus usual care, or usual care alone. Both groups will be assessed at baseline, and upon the completion of the program. Outcomes will include feasibility and safety factors such as recruitment, completion, adverse events, and intervention fidelity with qualitative evaluation along with mechanistic, physiological, and clinical outcomes.

Discussion

Results of this study will inform the rationale and methodological considerations for a full trial with long-term follow-up. Ultimately, further establishing the practicality and utility of home-based HIIT could provide an important exercise option for PwP, potentially leading to extended participation and increased health and well-being for this population.

Effectiveness of high-intensity interval training on peripheral brain-derived neurotrophic factor in adults: A systematic review and network meta-analysis

BACKGROUND

High-intensity interval training (HIIT) has emerged as an alternative training method to increase brain-derived neurotrophic factor (BDNF) levels, a crucial molecule involved in plastic brain changes. Its effect compared to moderate-intensity continuous training (MICT) is controversial. We aimed to estimate, and to comparatively evaluate, the acute and chronic effects on peripheral BDNF levels after a HIIT, MICT intervention or a control condition in adults.

METHODS

The CINAHL, Cochrane, PubMed, PEDro, Scopus, SPORTDiscus, and Web of Science databases were searched for randomized controlled trials (RCTs) from inception to June 30, 2023. A network meta-analysis was performed to assess the acute and chronic effects of HIIT versus control condition, HIIT versus MICT and MICT versus control condition on BDNF levels. Pooled standardized mean differences (SMDs) and their 95% confidence intervals (95% CIs) were calculated for RCTs using a random-effects model.

RESULTS

A total of 22 RCTs were selected for the systematic review, with 656 participants (aged 20.4-79 years, 34.0% females) and 20 were selected for the network meta-analysis. Network SMD estimates were significant for HIIT versus control condition (1.49, 95% CI: 0.61, 2.38) and MICT versus control condition (1.08, 95% CI: 0.04, 2.12) for acutely BDNF increase. However, pairwise comparisons only resulted in a significant effect for HIIT versus control condition.

CONCLUSIONS

HIIT is the best training modality for acutely increasing peripheral BDNF levels in adults. HIIT may effectively increase BDNF levels in the long term.

Effect of High-Intensity Interval Training and Moderate-Intensity Continuous Training in People With Poststroke Gait Dysfunction: A Randomized Clinical Trial

Background The exercise strategy that yields the greatest improvement in both cardiorespiratory fitness (V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ ) and walking capacity poststroke has not been determined. This study aimed to determine whether conventional moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT) have different effects on V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ and 6-minute walk distance (6MWD). Methods and Results In this 24-week superiority trial, people with poststroke gait dysfunction were randomized to MICT (5 days/week) or HIIT (3 days/week with 2 days/week of MICT). MICT trained to target intensity at the ventilatory anaerobic threshold. HIIT trained at the maximal tolerable treadmill speed/grade using a novel program of 2 work-to-recovery protocols: 30:60 and 120:180 seconds. V̇O2 and heart rate was measured during performance of the exercise that was prescribed at 8 and 24 weeks for treatment fidelity. Main outcomes were change in V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ and 6MWD. Assessors were blinded to the treatment group for V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ but not 6MWD. Secondary outcomes were change in ventilatory anaerobic threshold, cognition, gait-economy, 10-meter gait-velocity, balance, stair-climb performance, strength, and quality-of-life. Among 47 participants randomized to either MICT (n=23) or HIIT (n=24) (mean age, 62±11 years; 81% men), 96% completed training. In intention-to-treat analysis, change in V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ for MICT versus HIIT was 2.4±2.7 versus 5.7±3.1 mL·kg-1·min-1 (mean difference, 3.2 [95% CI, 1.5-4.8]; P<0.001), and change in 6MWD was 70.9±44.3 versus 83.4±53.6 m (mean difference, 12.5 [95% CI, -17 to 42]; P=0.401). HIIT had greater improvement in ventilatory anaerobic threshold (mean difference, 2.07 mL·kg-1·min-1 [95% CI, 0.59-3.6]; P=0.008). No other between-group differences were observed. During V̇O2 monitoring at 8 and 24 weeks, MICT reached 84±14% to 87±18% of V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ while HIIT reached 101±22% to 112±14% of V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ (during peak bouts). Conclusions HIIT resulted in more than a 2-fold greater and clinically important change in V ̇ O 2 peak $$ \dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}} $$ than MICT. Training to target (ventilatory anaerobic threshold) during MICT resulted in ~3 times the minimal clinically important difference in 6MWD, which was similar to HIIT. These findings show proof of concept that HIIT yields greater improvements in cardiorespiratory fitness than conventional MICT in appropriately screened individuals. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03006731.

Time-efficient, high-resistance inspiratory muscle strength training increases cerebrovascular reactivity in midlife and older adults

Aging is associated with increased risk for cognitive decline and dementia due in part to increases in systolic blood pressure (SBP) and cerebrovascular dysfunction. High-resistance inspiratory muscle strength training (IMST) is a time-efficient, intensive respiratory training protocol (30 resisted inspirations/day) that lowers SBP and improves peripheral vascular function in midlife/older adults with above-normal SBP. However, whether, and by what mechanisms, IMST can improve cerebrovascular function is unknown. We hypothesized that IMST would increase cerebrovascular reactivity to hypercapnia (CVR to CO2), which would coincide with changes to the plasma milieu that improve brain endothelial cell function and enhance cognitive performance (NIH Toolbox). We conducted a 6-wk double-blind, randomized, controlled clinical trial investigating high-resistance IMST [75% maximal inspiratory pressure (PImax); 6×/wk; 4 females, 5 males] vs. low-resistance sham training (15% PImax; 6×/wk; 2 females, 5 males) in midlife/older adults (age 50-79 yr) with initial above-normal SBP. Human brain endothelial cells (HBECs) were exposed to participant plasma and assessed for acetylcholine-stimulated nitric oxide (NO) production. CVR to CO2 increased after high-resistance IMST (pre: 1.38 ± 0.66 cm/s/mmHg; post: 2.31 ± 1.02 cm/s/mmHg, P = 0.020). Acetylcholine-stimulated NO production increased in HBECs exposed to plasma from after vs. before the IMST intervention [pre: 1.49 ± 0.33; post: 1.73 ± 0.35 arbitrary units (AU); P < 0.001]. Episodic memory increased modestly after the IMST intervention (pre: 95 ± 13; post: 103 ± 17 AU; P = 0.045). Cerebrovascular and cognitive function were unchanged in the sham control group. High-resistance IMST may be a promising strategy to improve cerebrovascular and cognitive function in midlife/older adults with above-normal SBP, a population at risk for future cognitive decline and dementia.NEW & NOTEWORTHY Midlife/older adults with above-normal blood pressure are at increased risk of developing cognitive decline and dementia. Our findings suggest that high-resistance inspiratory muscle strength training (IMST), a novel, time-efficient (5-10 min/day) form of physical training, may increase cerebrovascular reactivity to CO2 and episodic memory in midlife/older adults with initial above-normal blood pressure.

High-intensity interval training versus moderate-intensity continuous training on patient quality of life in cardiovascular disease: a systematic review and meta-analysis

This systematic review and meta-analysis aimed to compare the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on the quality of life (QOL) and mental health (MH) of patients with cardiovascular disease (CVDs). Web of Science, Medline, Embase, Cochrane (CENTRAL), CINAHL, China National Knowledge Infrastructure, Wanfang, and China Science and Technology Journal databases were searched from their date of establishment to July, 2023. A total of 5798 articles were screened, of which 25 were included according to the eligibility criteria. The weighted mean difference (WMD) and standardized mean difference (SMD) were used to analyze data from the same and different indicator categories, respectively. The fixed-effects model (FE) or random-effects model (RE) combined data based on the between-study heterogeneity. There were no statistically significant differences regarding QOL, physical component summary (PCS), mental component summary (MCS), and MH, including depression and anxiety levels, between the HIIT and MICT groups [SMD = 0.21, 95% confidence interval (CI)  - 0.18-0.61, Z = 1.06, P = 0.290; SMD = 0.10, 95% CI  - 0.03-0.23, Z = 1.52, P = 0.128; SMD = 0.07, 95% CI  - 0.05-0.20, Z = 1.13, P = 0.25; SMD = - 0.08, 95% CI  - 0.40-0.25, Z = - 0.46, P = 0.646; WMD = 0.14. 95% CI  - 0.56-0.84, Z = 0.39, P = 0.694, respectively]. HIIT significantly improved PCS in the coronary artery disease (CAD) population subgroup relative to MICT. HIIT was also significantly superior to MICT for physical role, vitality, and social function. We conclude that HIIT and MICT have similar effects on QOL and MH in patients with CVD, while HIIT is favorable for improving patients' self-perceived physiological functioning based on their status and social adjustment, and this effect is more significant in patients with CAD.

A Systematic Review on the Effects of Acute Aerobic Exercise on Neurophysiological, Molecular, and Behavioral Measures in Chronic Stroke

BACKGROUND

A single bout of aerobic exercise (AE) can produce changes in neurophysiological and behavioral measures in healthy individuals and those with stroke. However, the effects of AE-priming effects on neuroplasticity markers and behavioral measures are unclear.

OBJECTIVES

This systematic review aimed to examine the effects of AE on neuroplasticity measures, such as corticomotor excitability (CME), molecular markers, cortical activation, motor learning, and performance in stroke.

METHODS

A literature search was performed in MEDLINE, CINAHL, Scopus, and PsycINFO databases. Randomized and non-randomized studies incorporating acute AE in stroke were selected. Two reviewers independently assessed the risk of bias and methodological rigor of the studies and extracted data on participant characteristics, exercise interventions, and neuroplasticity related outcomes. The quality of transcranial magnetic stimulation reported methods was assessed using a standardized checklist.

RESULTS

A total of 16 studies were found suitable for inclusion. Our findings suggest mixed evidence for the effects of AE on CME, limited to no effects on intracortical inhibition and facilitation and some evidence for modulating brain derived neurotrophic factor levels, motor learning, and cortical activation. Exercise intensities in the moderate to vigorous range showed a trend towards better effects on neuroplasticity measures.

CONCLUSION

It appears that choosing a moderate to vigorous exercise paradigm for at least 20 to 30 minutes may induce changes in some neuroplasticity parameters in stroke. However, these findings necessitate prudent consideration as the studies were diverse and had moderate methodological quality. There is a need for a consensus on an exercise priming paradigm and for good-quality, larger controlled studies.

Feasibility of performing a multi-arm clinical trial examining the novel combination of repetitive transcranial magnetic stimulation and aerobic exercise for post-stroke depression

BACKGROUND

Post-stroke depression (PSD) occurs in approximately one-third of chronic stroke survivors. Although pharmacotherapy reduces depressive symptoms, side effects are common and stroke survivors have increased likelihood of multimorbidity and subsequent polypharmacy. Thus, alternative non-pharmacological treatments are needed. Combining two non-pharmacological anti-depressant treatments, aerobic exercise (AEx) and repetitive transcranial magnetic stimulation (rTMS), has been demonstrated to be feasible and well-tolerated in chronic stroke survivors.

OBJECTIVES

The purpose of this trial was to determine the feasibility of conducting a multi-arm combinatorial trial of rTMS and AEx and to provide an estimate of effect size of rTMS+AEx on PSD symptoms.

METHODS

Twenty-four participants were allocated to one of four treatment arms AEx, rTMS, rTMS+AEx, or non-depressed Control receiving AEx. All participants received a total of 24 treatment sessions. Participant adherence was the primary outcome measure for feasibility and within group effect sizes in Patient Health Questionnaire-9 (PHQ-9) score was the primary outcome for preliminary efficacy.

RESULTS

Mean adherence rates to the exercise intervention for AEx, rTMS+AEx, and Control subjects were 83%, 98%, and 95%, respectively. Mean adherence rates for rTMS and rTMS+AEx subjects were 97% and 99%, respectively. The rTMS and rTMS+AEx treatment groups demonstrated clinically significant reductions of 10.5 and 6.2 points in PHQ-9 scores, respectively.

CONCLUSION

Performing a multi-arm combinatorial trial examining the effect of rTMS+AEx on PSD appears feasible. All treatment arms demonstrated strong adherence to their respective interventions and were well received. rTMS and the combination of AEx with rTMS may be alternative treatments for PSD.

Change in Central Cardiovascular Function in Response to Intense Interval Training: A Systematic Review and Meta-analysis

INTRODUCTION

High-intensity interval training and sprint interval training significantly increase maximal oxygen uptake (V̇O 2max ), which enhances endurance performance and health status. Whether this response is due to increases in central cardiovascular function (cardiac output (CO) and blood volume) or peripheral factors is unknown.

PURPOSE

This study aimed to conduct a systematic review and meta-analysis to assess the effects of high-intensity interval training and sprint interval training (referred to as intense interval training) on changes in central cardiovascular function.

METHODS

We performed a systematic search of eight databases for studies denoting increases in V̇O 2max in which CO, stroke volume (SV), blood volume, plasma volume, end-diastolic/systolic volume, or hematocrit were measured.

RESULTS

Forty-five studies were included in this analysis, comprising 946 men and women of various health status (age and V̇O 2max , 20-76 yr and 13-61 mL·kg -1 ·min -1 ) who performed 6-96 sessions of interval training. Results showed an increase in V̇O 2max with intense interval training that was classified as a large effect ( d = 0.83). SV ( d = 0.69), and CO ( d = 0.49) had moderate effect sizes in response to intense interval training. Of 27 studies in which CO was measured, 77% exhibited significant increases in resting CO or that obtained during exercise. Similarly, 93% of studies revealed significant increases in SV in response to intense interval training. Effect sizes for these outcomes were larger for clinical versus healthy populations. Plasma volume, blood volume, and hematocrit had small effect sizes after training ( d = 0.06-0.14).

CONCLUSIONS

Increases in V̇O 2max demonstrated with intense interval training are attendant with increases in central O 2 delivery with little contribution from changes in hematocrit, blood volume, or plasma volume.

The impact of aerobic and resistance training intensity on markers of neuroplasticity in health and disease

OBJECTIVE

To determine the effects of low- vs. high-intensity aerobic and resistance training on motor and cognitive function, brain activation, brain structure, and neurochemical markers of neuroplasticity and the association thereof in healthy young and older adults and in patients with multiple sclerosis, Parkinson's disease, and stroke.

DESIGN

Systematic review and robust variance estimation meta-analysis with meta-regression.

DATA SOURCES

Systematic search of MEDLINE, Web of Science, and CINAHL databases.

RESULTS

Fifty studies with 60 intervention arms and 2283 in-analyses participants were included. Due to the low number of studies, the three patient groups were combined and analyzed as a single group. Overall, low- (g=0.19, p = 0.024) and high-intensity exercise (g=0.40, p = 0.001) improved neuroplasticity. Exercise intensity scaled with neuroplasticity only in healthy young adults but not in healthy older adults or patient groups. Exercise-induced improvements in neuroplasticity were associated with changes in motor but not cognitive outcomes.

CONCLUSION

Exercise intensity is an important variable to dose and individualize the exercise stimulus for healthy young individuals but not necessarily for healthy older adults and neurological patients. This conclusion warrants caution because studies are needed that directly compare the effects of low- vs. high-intensity exercise on neuroplasticity to determine if such changes are mechanistically and incrementally linked to improved cognition and motor function.

The Effect of Endurance Training on Serum BDNF Levels in the Chronic Post-Stroke Phase: Current Evidence and Qualitative Systematic Review

Research in modern neurorehabilitation focusses on cognitive and motor recovery programmes tailored to each stroke patient, with particular emphasis on physiological parameters. The objectives of this review were to determine whether a single bout of endurance activity or long-term endurance activity regulates exercise-dependent serum brain-derived neurotrophic factor (BDNF) levels and to evaluate the methodological quality of the studies. To assess the effectiveness of endurance exercise among patients in the chronic post-stroke phase, a systematic review was performed, including searching EBSCOhost, PEDro, PubMed, and Scopus for articles published up to the end of October 2021. The PRISMA 2020 outline was used, and this review was registered on PROSPERO. Of the 180 papers identified, seven intervention studies (comprising 200 patients) met the inclusion criteria. The methodological quality of these studies was evaluated by using the Physiotherapy Evidence Database (PEDro) criteria. The effect of exercise was evaluated in four studies with a single bout of endurance activity, two studies with long-term endurance activity, and one study with a single bout of endurance activity as well as long-term endurance activity. The results of our systematic review provide evidence that endurance exercise might augment the peripheral BDNF concentration in post-stroke individuals.

Effects of two different exercise paradigms on cardiac function, BDNF-TrkB expression, and myocardial protection in the presence and absence of Western diet

Background

Brain-derived neurotrophic factor (BDNF) -tropomyosin-related kinase receptor B (TrkB) signaling is a vital regulator of myocardial performance. Here, we tested the impact of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on heart function, metabolic parameters, and serum/cardiac BDNF (with its TrkB receptor) in animals fed a Western (WD) or regular diet (ND). Further, myocardial expression of pro-inflammatory cytokine interleukin-18 (IL-18) and cardioprotective molecule heme oxygens-1 (HO-1) were monitored.

Methods

Wistar rats were divided into HIIT, MICT, and sedentary (SED), all fed a WD or ND, for 12 weeks. Heart function, protein expression, and serum factors were assessed via echocardiography, western blotting, and ELISA, respectively.

Results

WD plus SED caused insulin resistance, dyslipidemia, visceral fat deposition, serum BDNF depletion as well as cardiac upregulation of IL-18 and downregulation of HO-1, without affecting, heart function and BDNF-TrkB expression. The cardiometabolic risk factors, serum BDNF losses, and IL-18 overexpression were similarly obviated by HIIT and MICT, although HO-1 expression was boosted by HIIT exclusively (even in ND). HIIT enhanced heart function, regardless of the diet. HIIT augmented cardiac BDNF expression, with a significant difference between ND and WD. Likewise, HIIT instigated TrkB expression only in ND.

Conclusions

HIIT and MICT can cope with myocardial inflammation and cardiometabolic risk factors in WD consumers and, exclusively, HIIT may grant further protection by increasing heart function, BDNF-TrkB expression, and HO-1 expression. Thus, the HIIT paradigm should be considered as a preference for subjects who require heart function to be preserved or enhanced.

Stepper-Based Training Improves Monocyte-Platelet Aggregation and Thrombin Generation in Nonambulatory Hemiplegic Patients

PURPOSE

Nonambulatory stroke patients are extremely sedentary, but most available data concerning exercise training in stroke patients are related to ambulatory patients. This study aimed to investigate the efficacy of stepper-based exercise training on cardiopulmonary fitness, monocyte subtypes, and associated monocyte-platelet aggregates (MPA) and thrombin generation (TrG) in nonambulatory hemiplegic patients with ischemic stroke.

METHOD

Thirty-eight patients were randomized into exercise training (ET, n = 20) and usual care (UC, n = 18) groups. The ET underwent supervised exercise training (60% peak work rate) using a recumbent stepper for two to four sessions per week and 36 sessions in total. In addition, 12 healthy participants were enrolled as healthy controls. Monocyte characteristics, MPA, and plasma TrG kinetics were determined before and after intervention by flow cytometry and calibrated automated thrombogram® (CAT).

RESULTS

Seventeen and 15 patients completed the protocol in the ET and UC groups. Peak V̇O2 improved in ET (15.7 ± 4.8 vs 18.9 ± 5.3 mL·min-1·kg-1, +20%), so did the phase angle of the hemiplegic limbs. The counts of total MPA and MPA associated with three monocyte subtypes, alongside CD42b expression all declined in ET with subtypes 2 and 1 being the most prominent. Macrophage inflammatory protein 1β (MIP-1 β) level also declined. The TrG kinetics was attenuated after ET by delaying initiation and reducing the rising slope and peak of thrombin production. In UC, no difference was revealed in the pre-post comparison.

CONCLUSIONS

Stepper-based ET is feasible in nonambulatory hemiplegic patients and is effective in improving aerobic fitness. Moreover, it decreases heteroaggregation of monocytes with platelets, especially in monocyte subtypes 2 and 1. Thrombin generation was also attenuated. Hence, stepper-based ET may be incorporated in the rehabilitation of nonambulatory hemiplegic patients.

What are the effects of acute exercise and exercise training on cerebrovascular hemodynamics following stroke? A systematic review and meta-analysis

INTRODUCTION

Limited data exist regarding the effects of acute exercise and exercise training on cerebrovascular hemodynamic variables post-stroke.

PURPOSE

This systematic review and meta-analysis 1) examined the effects of acute exercise and exercise training on cerebrovascular hemodynamic variables reported in the stroke exercise literature; and 2) synthesized the peak middle cerebral artery blood velocity (MCAv) achieved during an acute bout of moderate-intensity exercise in individuals post-stroke.

METHODS

Six databases (MEDLINE, EMBASE, Web of Science, CINAHL, PsycINFO, AMED) were searched from inception to December 1^st 2021, for studies that examined the effect of acute exercise or exercise training on cerebrovascular hemodynamics in adults post-stroke. Two reviewers conducted title and abstract screening, full-text evaluation, data extraction, and quality appraisal. Random effects models were used in meta-analysis.

RESULTS

Nine studies, including 4 acute exercise (n=61) and 5 exercise training studies (n=193), were included. Meta-analyses were not statistically feasible for several cerebrovascular hemodynamic variables. Descriptive analysis reveals that exercise training may increase cerebral blood flow and cerebrovascular reactivity to carbon dioxide among individuals post-stroke. Meta-analysis of three acute exercise studies revealed no significant changes in MCAv during acute moderate intensity exercise (n=48 participants, mean difference = 5.2 cm/s, 95% CI [-0.6, 11.0], P=0.08) compared to resting MCAv values.

CONCLUSION

This review suggests that individuals post-stroke may have attenuated cerebrovascular hemodynamics as measured by the MCAv during acute moderate-intensity exercise. Higher quality research utilizing agreed upon hemodynamic variables are needed to synthesize the effects of exercise training on cerebrovascular hemodynamics post-stroke.

Research on control method of upper limb exoskeleton based on mixed perception model

As one of the research hotspots in the field of rehabilitation robotics, the upper limb exoskeleton robot has been widely used in the field of rehabilitation. However, the existing methods cannot comprehensively and accurately reflect the motion state of patients, which may lead to overtraining and secondary injury of patients in the process of rehabilitation training. In this paper, an upper limb exoskeleton control method based on mixed perception model of motion intention and intensity is proposed, which is based on the 6 degree-of-freedom upper limb rehabilitation exoskeleton in the laboratory. First, the kinematic information and heart rate information in the rehabilitation process of patients are collected, corresponding to patients’ motion intention and motion intensity, and fused to obtain the mixed perception vector. Second, the motion perception model based on long short-term memory neural network is established to realize the prediction of upper limb motion trajectory of patients and compared with back-propagation neural network to prove its effectiveness. Finally, the control system is built, and both offline and online test of the control method proposed are implemented. The experimental results show that the method can achieve comprehensive motion state perception of patients, realize real-time and accurate prediction trajectory according to human motion intention and intensity. The average prediction accuracy is 95.3%, and predicted joint angle error is less than 5 degrees. Therefore, the control method based on mixed perception model has good robustness and universality, which provides a new method for the active control of upper limb exoskeleton.

The impact Of high-intensity interval training On functioning And health-related quality Of life In post-stroke patients: A systematic review With meta-analysis

OBJECTIVE

To examine the effects of high-intensity interval training on the functioning and health-related quality of life of post-stroke patients.

METHODS

We searched the following electronic databases: MEDLINE/Pubmed, Cochrane Central Register of Controlled Trials, PEDro database, and Scielo up to January 2022 for randomized controlled trials that investigated the effects of high-intensity interval training in post-stroke patients. Two reviewers selected the studies independently. Study quality was evaluated using the PEDro scale. The mean difference (MD), standard mean difference (SMD), and 95% confidence intervals (CIs) were calculated.

RESULTS

Nine studies met the study criteria (375 patients). The age of the participants ranged from 55.8 to 72.1 years. The studies included patients within 2 weeks of stroke onset to patients longer than 1 month of stroke. High-intensity interval training resulted in improvement in cardiorespiratory fitness (peak oxygen uptake) MD (3.8 mL/kg/min, 95% CI: 2.62, 5.01, n  =  91), balance MD 5.7 (95% CI: 3.50, 7.91; N = 64), and gait speed SMD (0.2 m/s; 95% CI: 0.05, 0.27; N = 100) compared with continuous aerobic training. The health-related quality of life did not differ between the groups. Compared to usual care, high-intensity interval training improved the cardiorespiratory fitness SMD (0.5 95% CI: 0.14, 0.81, n  =  239). No serious adverse events were observed.

CONCLUSIONS

The findings of this systematic review show that high-intensity interval training was more efficient than continuous aerobic training to gain cardiorespiratory fitness, balance and gait speed in post-stroke patients. In addition, compared to usual care, high-intensity interval training improved cardiorespiratory fitness.

Supervised Cycling Training Improves Erythrocyte Rheology in Individuals With Peripheral Arterial Disease

Peripheral arterial disease (PAD) results in insufficient flow to lower extremities. Aerobic exercise provides health benefits for individuals with PAD, but basic science behind it is still debated. Twenty-one PAD patients aged about 70 years with female/male as 7/14 were recruited. Among them, 11 were randomized to have supervised cycling training (SCT) and 10 to receive general healthcare (GHC) as controls. SCT participants completed 36 sessions of SCT at the first ventilation threshold within 12 weeks and the controls received GHC for 12 weeks. Ankle-brachial index (ABI), 6-min walk test (6MWT), peak oxygen consumption (V˙O_2peak), minute ventilation (V˙_E), minute carbon dioxide production (V˙CO₂), erythrocyte rheology, including the maximal elongation index (EI_max) and shear stress at 50% of maximal elongation (SS_1/2), and the Short Form-36 (SF-36) questionnaire for quality of life (QoL) were assessed before and 12 weeks after initial visit. SCT significantly decreased the SS_1/2 as well as SS_1/2 to EI_max ratio (SS_1/2/EI_max) and increased the erythrocyte osmolality in the hypertonic region as well as the area under EI-osmolality curve. The supervised exercise-induced improvement of erythrocyte deformability could contribute to the increased peripheral tissue O₂ delivery and was possibly related with increased V˙O_2peak. The physiological benefit was associated with significantly increased ABI, 6-min walking distance, cardiorespiratory fitness, and SF-36 score. However, no significant changes in aerobic capacity and erythrocyte rheological properties were observed after 12-week of GHC. In conclusion, SCT improves aerobic capacity by enhancing erythrocyte membrane deformability and consequently promotes QoL in PAD patients.

The Exercising Brain: An Overlooked Factor Limiting the Tolerance to Physical Exertion in Major Cardiorespiratory Diseases?

“Exercise starts and ends in the brain”: this was the title of a review article authored by Dr. Bengt Kayser back in 2003. In this piece of work, the author highlights that pioneer studies have primarily focused on the cardiorespiratory-muscle axis to set the human limits to whole-body exercise tolerance. In some circumstances, however, exercise cessation may not be solely attributable to these players: the central nervous system is thought to hold a relevant role as the ultimate site of exercise termination. In fact, there has been a growing interest relative to the “brain” response to exercise in chronic cardiorespiratory diseases, and its potential implication in limiting the tolerance to physical exertion in patients. To reach these overarching goals, non-invasive techniques, such as near-infrared spectroscopy and transcranial magnetic stimulation, have been successfully applied to get insights into the underlying mechanisms of exercise limitation in clinical populations. This review provides an up-to-date outline of the rationale for the “brain” as the organ limiting the tolerance to physical exertion in patients with cardiorespiratory diseases. We first outline some key methodological aspects of neuromuscular function and cerebral hemodynamics assessment in response to different exercise paradigms. We then review the most prominent studies, which explored the influence of major cardiorespiratory diseases on these outcomes. After a balanced summary of existing evidence, we finalize by detailing the rationale for investigating the “brain” contribution to exercise limitation in hitherto unexplored cardiorespiratory diseases, an endeavor that might lead to innovative lines of applied physiological research.

Associations Between Time After Stroke and Exercise Training Outcomes: A Meta-Regression Analysis

Background Knowledge gaps exist regarding the effect of time elapsed after stroke on the effectiveness of exercise training interventions, offering incomplete guidance to clinicians. Methods and Results To determine the associations between time after stroke and 6-minute walk distance, 10-meter walk time, cardiorespiratory fitness and balance (Berg Balance Scale score [BBS]) in exercise training interventions, relevant studies in post-stroke populations were identified by systematic review. Time after stroke as continuous or dichotomized (≤3 months versus >3 months, and ≤6 months versus >6 months) variables and weighted mean differences in postintervention outcomes were examined in meta-regression analyses adjusted for study baseline mean values (pre-post comparisons) or baseline mean values and baseline control-intervention differences (controlled comparisons). Secondary models were adjusted additionally for mean age, sex, and aerobic exercise intensity, dose, and modality. We included 148 studies. Earlier exercise training initiation was associated with larger pre-post differences in mobility; studies initiated ≤3 months versus >3 months after stroke were associated with larger differences (weighted mean differences [95% confidence interval]) in 6-minute walk distance (36.3 meters; 95% CI, 14.2-58.5), comfortable 10-meter walk time (0.13 m/s; 95% CI, 0.06-0.19) and fast 10-meter walk time (0.16 m/s; 95% CI, 0.03-0.3), in fully adjusted models. Initiation ≤3 months versus >3 months was not associated with cardiorespiratory fitness but was associated with a higher but not clinically important Berg Balance Scale score difference (2.9 points; 95% CI, 0.41-5.5). In exercise training versus control studies, initiation ≤3 months was associated with a greater difference in only postintervention 6-minute walk distance (baseline-adjusted 27.3 meters; 95% CI, 6.1-48.5; fully adjusted, 24.9 meters; 95% CI, 0.82-49.1; a similar association was seen for ≤6 months versus >6 months after stroke (fully adjusted, 26.6 meters; 95% CI, 2.6-50.6). Conclusions There may be a clinically meaningful benefit to mobility outcomes when exercise is initiated within 3 months and up to 6 months after stroke.

Can high-intensity interval training improve mental health outcomes in the general population and those with physical illnesses? A systematic review and meta-analysis

OBJECTIVE

High-intensity interval training (HIIT) is a safe and feasible form of exercise. The aim of this meta-analysis was to investigate the mental health effects of HIIT, in healthy populations and those with physical illnesses, and to compare the mental health effects to non-active controls and other forms of exercise.

DESIGN

Random effects meta-analyses were undertaken for randomised controlled trials (RCTs) comparing HIIT with non-active and/or active (exercise) control conditions for the following coprimary outcomes: mental well-being, symptoms of depression, anxiety and psychological stress. Positive and negative affect, distress and sleep outcomes were summarised narratively.

DATA SOURCES

Medline, PsycINFO, Embase and CENTRAL databases were searched from inception to 7 July 2020.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

RCTs that investigated HIIT in healthy populations and/or those with physical illnesses and reported change in mental well-being, depression, anxiety, psychological stress, positive/negative affect, distress and/or sleep quality.

RESULTS

Fifty-eight RCTs were retrieved. HIIT led to moderate improvements in mental well-being (standardised mean difference (SMD): 0.418; 95% CI: 0.135 to 0.701; n=12 studies), depression severity (SMD: -0.496; 95% CI: -0.973 to -0.020; n=10) and perceived stress (SMD: -0.474; 95% CI: -0.796 to -0.152; n=4) compared with non-active controls, and small improvements in mental well-being compared with active controls (SMD:0.229; 95% CI: 0.054 to 0.403; n=12). There was a suggestion that HIIT may improve sleep and psychological distress compared with non-active controls: however, these findings were based on a small number of RCTs.

CONCLUSION

These findings support the use of HIIT for mental health in the general population.

LEVEL OF EVIDENCE

The quality of evidence was moderate-to-high according to the Grading of Recommendations Assessment, Development and Evaluation) criteria.

PROSPERO REGISTRATION NUMBER

CRD42020182643.

Is High-Intensity Interval Training Suitable to Promote Neuroplasticity and Cognitive Functions after Stroke?

Stroke-induced cognitive impairments affect the long-term quality of life. High-intensity interval training (HIIT) is now considered a promising strategy to enhance cognitive functions. This review is designed to examine the role of HIIT in promoting neuroplasticity processes and/or cognitive functions after stroke. The various methodological limitations related to the clinical relevance of studies on the exercise recommendations in individuals with stroke are first discussed. Then, the relevance of HIIT in improving neurotrophic factors expression, neurogenesis and synaptic plasticity is debated in both stroke and healthy individuals (humans and rodents). Moreover, HIIT may have a preventive role on stroke severity, as found in rodents. The potential role of HIIT in stroke rehabilitation is reinforced by findings showing its powerful neurogenic effect that might potentiate cognitive benefits induced by cognitive tasks. In addition, the clinical role of neuroplasticity observed in each hemisphere needs to be clarified by coupling more frequently to cellular/molecular measurements and behavioral testing.