Effects of exercise training on heart rate variability in individuals with lower extremity arterial disease and claudication: A systematic review.

PURPOSE: To perform a systematic review of studies assessing the effects of regular exercise on heart rate variability (HRV) in individuals with lower extremity arterial disease (LEAD) and symptoms of claudication. METHODS: A systematic search in the electronic databases MEDLINE, Embase, and Scielo, was conducted and updated on January 21, 2023. Randomized clinical trials investigating patients with LEAD and IC, assessing ≥ 4 wk of exercise interventions, and reporting at least one HRV measure (e.g., time or frequency domains) at baseline and follow-up were included. Two reviewers independently screened studies for inclusion, performed data extraction, and quality assessment of included studies. RESULTS: Data from 7 trials were included (i.e., 5 walking, 1 resistance, and 1 isometric handgrip training), totaling 327 patients (66% males; range: 61 - 68 yr; ankle brachial index: 0.4 - 0.7). Following exercise training, three studies investigating walking training reported an increase in parasympathetic modulation indices and/or a decrease in sympathetic modulation indices (n = 2) as well as an increase in non-linear indices (n = 1). CONCLUSION: The current evidence is weak, and larger randomized controlled trials are needed to confirm the efficacy of exercise training in improving HRV. Additionally, the high divergence in the methodology of studies indicated the need for standard tools to improve the quality of HRV measurements in exercise trials. It is recommended to use standard procedures in future trials investigating HRV.

Moderate- and High-Intensity Inspiratory Muscle Training Equally Improves Inspiratory Muscle Strength and Endurance-A Double-Blind Randomized Controlled Trial.

BACKGROUND AND OBJECTIVE: Inspiratory muscle training (IMT) produced outstanding results in the physical performance of active subjects; however, little is known about the best training intensity for this population. The objective was to investigate the impact of an IMT of high intensity, using the critical inspiratory pressure (CIP), on inspiratory muscle strength (IMS), inspiratory muscle endurance (IME), peak power, and oxygen uptake of recreational cyclists; and to compare these results with moderate-intensity IMT (60% of maximal inspiratory pressure [MIP]). METHODS: Thirty apparently healthy male recreational cyclists, 20-40 years old, underwent 11 weeks of IMT (3 times per week; 55 min per session). Participants were randomized into 3 groups: sham group (6 cmH2O; n = 8); 60% MIP (MIP60; n = 10) and CIP (n = 12). All participants performed the IMS test and incremental IME test at the first, fifth, ninth, and 13th weeks of the experimental protocol. Cardiopulmonary exercise testing was performed on an electromagnetic braking cycle ergometer pre-IMT and post-IMT. Data were analyzed using a 2-way repeated measures ANOVA (group and period factors). RESULTS: IMS increased in CIP and MIP60 groups at the ninth and 13th weeks compared with the sham group (P < .001; ß = 0.99). Regarding IME, there was an interaction between the CIP and MIP60 groups in all periods, except in the initial evaluation (P < .001; ß = 1.00). Peak power (in watts) increased after IMT in CIP and MIP60 groups (P = .01; ß = 0.67). Absolute oxygen uptake did not increase after IMT (P = .49; ß = 0.05). Relative oxygen uptake to lean mass values did not change significantly (P = .48; ß = 0.05). CONCLUSION: High-intensity IMT is beneficial on IMS, IME, and peak power, but does not provide additional gain to moderate intensity in recreational cyclists.

Can respiratory muscle training change the blood pressure levels in hypertension? A systematic review with meta-analysis.

The aim was to systematically review randomized controlled trials investigating the effects of respiratory training on blood pressure control in hypertensive individuals. Systematic review with meta-analysis was coducted following the guidelines from PRISMA statement. Searches for randomized controlled trials were performed in four electronic databases (PubMed, Cochrane Library, SCOPUS, and PEDro). Studies were included if they were randomized controlled trials that examined the impact of respiratory training on blood pressure of individuals with systemic arterial hypertension and the patients had no other associated disease. Eight studies were included for final analysis (total of 270 participants; 18-85 years) and presented an average score of 6.25 in the PEDro scale, being considered of high methodological quality. The meta-analysis showed a reduction in systolic and diastolic blood pressure for respiratory training when the load was applied [-15.72 (-18.63; -12.81) and -7.08 (-9.03; -5.13) mmHg, respectively]. There was also a reduction in systolic, but not in diastolic blood pressure when the training was performed without load [-5.08 (-7.49; -2.66) and -1.04 (-2.55; +0.46) mmHg, respectively]. The respiratory training has a positive effect in BP in hypertensive patients, however, only when performed with load seems to be able to promote some beneficial effect on diastolic blood pressure reduction.

Metabolomics-Based Studies Assessing Exercise-Induced Alterations of the Human Metabolome: A Systematic Review.

This systematic review provides a qualitative appraisal of 24 high-quality metabolomics-based studies published over the past decade exploring exercise-induced alterations of the human metabolome. Of these papers, 63% focused on acute metabolite changes following intense and prolonged exercise. The best studies utilized liquid chromatography mass spectrometry (LC-MS/MS) analytical platforms with large chemical standard libraries and strong, multivariate bioinformatics support. These studies reported large-fold changes in diverse lipid-related metabolites, with more than 100 increasing two-fold or greater within a few hours post-exercise. Metabolite shifts, even after strenuous exercise, typically return to near pre-exercise levels after one day of recovery. Few studies investigated metabolite changes following acute exercise bouts of shorter durations (< 60 min) and workload volumes. Plasma metabolite shifts in these types of studies are modest in comparison. More cross-sectional and exercise training studies are needed to improve scientific understanding of the human system's response to varying, chronic exercise workloads. The findings derived from this review provide direction for future investigations focused on the body's metabolome response to exercise.

Assessment of the Coupling Strength of Cardiovascular Control via Joint Symbolic Analysis during Postural Challenge in Recreational Athletes.

Short-term cardiovascular control, comprising cardiac baroreflex and mechanisms governing cardiac contractility and vascular properties, links heart period (HP) and systolic arterial pressure (SAP) fluctuations. It is activated during postural challenge and this activation is traditionally quantified via linear tools such as HP-SAP squared coherence function. In this study the ability of a nonlinear bivariate tool based on joint symbolic analysis (JSA) approach was tested against HP-SAP coherence function during orthostatic challenge in recreational athletes. We studied 9 men healthy cycling practitioners (age: 20-40 yrs) at rest in supine condition (REST) and during active standing (STAND). The JSA method is based on the definition of symbolic HP and SAP patterns and on the evaluation of the rate of their simultaneous occurrence in both HP and SAP series. HP-SAP squared coherence was computed in the low frequency band (LF, from 0.04 to 0.15 Hz). We found the expected response to the postural stimulus, namely the increase of sympathetic modulation and the contemporaneous vagal withdrawal. However, only JSA was able to detect the expected increase of association between HP and SAP variability series over slow time scales. This result suggests that recreational athletes have more relevant nonlinear interactions between HP and SAP that might be missed by traditional linear tools and might require nonlinear tools to be efficiently described.