The effects of inspiratory muscle training on exercise tolerance in patients with post-covid-19 syndrome: a systematic review.

The present study aimed to clarify the effects of inspiratory muscle training (IMT) and expiratory muscle training (EMT) on ventilatory muscle strength, pulmonary function and responses during exercise testing. Young healthy women were randomly assigned to 3 groups: IMT (n=16); EMT (n=16); or untrained normal controls (NC, n=8). Subjects in the IMT and EMT groups trained for 15 minutes twice daily over 2 weeks at loads of 30% maximal inspiratory and expiratory muscle strength, respectively. Ventilatory muscle strength (maximal inspiratory and expiratory muscle strength; PImax and PEmax, respectively), pulmonary function and progressive exercise testing was performed. Both PImax and PEmax increased in the IMT group, and PEmax increased in the EMT group. Neither trained group demonstrated any change in pulmonary function or peak values during exercise testing. In the IMT group, exercise-induced increases in heart rate, oxygen uptake (VO2/kg) and rating of perceived exertion (RPE) decreased with training, as did increases in VO2/kg and RPE in the EMT group. The increased ventilatory muscle strength in both IMT and EMT groups might improve ventilatory efficacy during exercise, and increased inspiratory muscle strength might facilitate oxygen delivery through improved circulatory responses.

Effects of high intensity interval-based inspiratory muscle training in patients with heart failure: A single-blind randomized controlled trial

Background: Exercise intolerance and dyspnea are the main symptoms of heart failure (HF) patients. Inspiratory muscle weakness is a predictor of mortality in these patients. Aerobic training (AT) is strongly recommended for the treatment of HF patients. This modality of exercise increase pulmonary ventilation. It is unclear if this is sufficient to improve inspiratory muscle strenght in HF patients. Objectives: To compare the effects of inspiratory muscle training (IMT) and AT on inspiratory muscle strength in patients with systolic HF. Methods: Patients aged 30-70 years with NYHA II-III chronic systolic HF, LVEF≤40%, body mass index Results: Only IMT significantly increased MIP (-86±9 vs -106±9 cmH2O) and Pdi Tw (28±7 vs 36±8 cmH2O). There was a tendency towards improve MIP in AT group (-91±10 vs -94±10cmH2O, P=0.09). No differences was observed in UN group. Conclusions: IMT improves overall inspiratory muscle and diaphragmatic muscle strength in HF patients. AT seems improve only overall inspiratory muscle strength but not diaphragmatic muscle strength in chronic systolic HF patients.

Patients with COPD may experience respiratory muscle weakness. Two therapeutic approaches to the respiratory muscles are inspiratory muscle training and calisthenics-and-breathing exercises. The aims of the study are to compare the effects of inspiratory muscle training and calisthenics-and-breathing exercises associated with physical training in subjects with COPD as an additional benefit of strength and endurance of the inspiratory muscles, thoracoabdominal mobility, physical exercise capacity, and reduction in dyspnea on exertion. In addition, these gains were compared between subjects with and without respiratory muscle weakness. 25 subjects completed the study: 13 composed the inspiratory muscle training group, and 12 composed the calisthenics-and-breathing exercises group. Subjects were assessed before and after training by spirometry, measurements of respiratory muscle strength and test of inspiratory muscle endurance, thoracoabdominal excursion measurements, and the 6-min walk test. Moreover, scores for the Modified Medical Research Council dyspnea scale were reported. After intervention, there was a significant improvement in both groups of respiratory muscle strength and endurance, thoracoabdominal mobility, and walking distance in the 6-min walk test. Additionally, there was a decrease of dyspnea in the 6-min walk test peak. A difference was found between groups, with higher values of respiratory muscle strength and thoracoabdominal mobility and lower values of dyspnea in the 6-min walk test peak and the Modified Medical Research Council dyspnea scale in the inspiratory muscle training group. In the inspiratory muscle training group, subjects with respiratory muscle weakness had greater gains in inspiratory muscle strength and endurance. Both interventions increased exercise capacity and decreased dyspnea during physical effort. However, inspiratory muscle training was more effective in increasing inspiratory muscle strength and endurance, which could result in a decreased sensation of dyspnea. In addition, subjects with respiratory muscle weakness that performed inspiratory muscle training had higher gains in inspiratory muscle strength and endurance but not of dyspnea and submaximal exercise capacity. (ClinicalTrials.gov registration NCT01510041.).

Background: Fatiguing contractions of the inspiratory muscles may increase sympathetic tonus leading to peripheral vasoconstriction in healthy individuals. The so-called “inspiratory muscle metaboreflex” (IMM) is thought to be particularly active during heavy intensity exercise in order to deviate blood flow from locomotor to respiratory muscles. It remains unclear whether this phenomenon is also present in patients with COPD. Aims: To assess the effects of inspiratory muscle training (IMT) on leg blood flow and resistance during inspiratory resistance and exercise tolerance in COPD patients. Methods: Patients were randomized to IMT (30% of maximal inspiratory pressure; MIP) or SHAM (without resistance) intervention 30 min/day, 7 times/week, for 8 weeks using Power-breathTM (Southam, UK). High intensity constant load cardiopulmonary exercise test and IMM induction (60% of MIP until exhaustion) with calf blood flow (CBF) measurement by venous occlusion plethysmography (HokansonTM, USA) were performed before and after training. Results: 7 patients in IMT and 6 patients in SHAM group completed the study (66.8±9.1yr; FEV1= 37±13% pred; MIP=88±32cmH2O). When compared to SHAM, IMT significantly improved exercise tolerance (Δtlim; 15±65 vs 191±247s; p=0.05). There were no significant between-group differences regarding to CBF and calf vascular resistance (CVR). In addition, CBF and CVR after both interventions did not differ from baseline (p>0.05). Conclusions: IMT with 30% of MIP enhanced exercise tolerance in comparison to SHAM training in patients with COPD. This finding seems not to be mechanistically related to improvements in leg blood flow.

Declining inspiratory muscle function and structure and systemic low-level inflammation and oxidative stress may contribute to morbidity and mortality during normal ageing. Therefore, we examined the effects of inspiratory muscle training (IMT) in older adults on inspiratory muscle function and structure and systemic inflammation and oxidative stress, and reexamined the reported positive effects of IMT on respiratory muscle strength, inspiratory muscle endurance, spirometry, exercise performance, physical activity levels (PAL), and quality of life (QoL). Thirty-four healthy older adults (68 ± 3 yr) with normal spirometry, respiratory muscle strength, and physical fitness were divided equally into a pressure-threshold IMT or sham-hypoxic placebo group. Before and after an 8-wk intervention, measurements were taken for dynamic inspiratory muscle function and inspiratory muscle endurance using a weighted plunger pressure-threshold loading device; diaphragm thickness by using B-mode ultrasonography; plasma cytokine concentrations by using immunoassays; DNA damage levels in peripheral blood mononuclear cells by using comet assays; spirometry, maximal mouth pressures, and exercise performance by using a 6-min walk test; PAL by using a questionnaire and accelerometry; and QoL using a questionnaire. Compared with placebo, IMT increased maximal inspiratory pressure (+34% ± 43%, P = 0.008), diaphragm thickness at residual volume (+38% ± 39%, P = 0.03), and peak inspiratory flow (+35% ± 42%, P = 0.049) but did not change other spirometry measures, plasma cytokine concentrations, DNA damage levels in peripheral blood mononuclear cells, dynamic inspiratory muscle function, inspiratory muscle endurance, exercise performance, PAL, or QoL. These novel data indicate that in healthy older adults, IMT elicits some positive changes in inspiratory muscle function and structure but neither attenuates systemic inflammation and oxidative stress nor improves exercise performance, PAL, or QoL.

ABSTRACTThis study was conducted to determine the effects of inspiratory muscle training (IMT) on respiratory and peripheral muscles oxygenation during a maximal exercise tolerance test and on repeated-sprint ability (RSA) performance in professional women football players. Eighteen athletes were randomly assigned to one of the following groups: SHAM (n = 8) or IMT (n = 10). After a maximal incremental exercise test, all participants performed (on a different day) a time-to-exhaustion (Tlim) test. Peripheral and respiratory muscles oxygenation by near-infrared spectroscopy, breath-by-breath ventilatory and metabolic variables, and blood lactate concentration were measured. The RSA test was performed on a grass field. After a 6 week intervention, all athletes were reevaluated. Both groups showed increases in inspiratory muscles strength, exercise tolerance and RSA performance, however only the IMT group presented lower deoxyhemoglobin and total hemoglobin blood concentrations on intercostal muscles concomitantly to an increased oxyhemoglobin and total hemoglobin blood concentrations on vastus lateralis muscle during Tlim. In conclusion, these results may indicate the potential role of IMT to attenuate inspiratory muscles metaboreflex and consequently improve oxygen and blood supply to limb muscles during high-intensity exercise, with a potential impact on inspiratory muscle strength, exercise tolerance and sprints performance in professional women football players.

<h3>Objectives</h3> We investigated the effect of inspiratory muscle training (IMT) on inspiratory muscle strength, functional capacity and respiratory muscle kinematics during exercise in older adults. <h3>Methods</h3> 24 older adults (age: 68.3±2.5 years) were evenly randomised into an experimental (IMT) or control (SHAM-IMT) group. Both groups performed 30 breaths, twice daily, for 8 weeks, with the IMT group training at an intensity of ~50% maximal inspiratory pressure (PImax) and the SHAM-IMT group training at an intensity of &lt;15% PImax. Measurements of PImax, breathing discomfort (Borg scale ratings) during a bout of IMT at 50% PImax, 6MWT, accelerometry-assessed physical activity levels, and balance (mini-BEST), were assessed pre- and post-intervention. Furthermore, respiratory muscle kinematics were assessed via optoelectronic plethysmography (OEP) during constant work rate cycling at the same absolute intensity (75% predicted peak work rate) before and after training. Participant views towards the intervention were explored via interviews. <h3>Results</h3> Inspiratory muscle strength (reflected by an increased PImax) was significantly improved in the IMT group (by 20.0±11.9 cmH₂O; p=0.001) but not in the SHAM-IMT group (by 2.24±9.3 cmH₂O). Breathing discomfort ratings significantly decreased (from 3.5±0.9 to 1.7±0.8) following IMT but did not change (3.6±1.0 to 3.3±1.2) in SHAM-IMT. The 6MWD increased by 18.8±28.4 m (p=0.042) in the IMT group with no change (-0.4±29.0 m) in SHAM-IMT. Sedentary time was decreased following IMT (by 28.0±39.8 min; p=0.042), and the reactive component within the mini-BEST balance was improved (by 1.2±0.8; p&lt;0.001) in the IMT group only. OEP measures showed a significantly greater contribution of the pulmonary and abdominal rib cage compartments to the total tidal volume (V_T) expansion only in the IMT group. Older adults reported positive experiences with IMT, highlighting facilitators such as ease of use and sessions not being time-consuming. <h3>Conclusions</h3> IMT significantly improved inspiratory muscle strength, IMT-induced breathing discomfort, and functional capacity in this population. Observations of respiratory muscle kinematics during exercise suggest greater expansion of the rib cage compartment following IMT, potentially due to a greater contribution of intercostal muscles and the diaphragm. Qualitative measures revealed that IMT is well-tolerated in healthy older adults.

Randomized Controlled Trial of the Effect of Inspiratory Muscle Training and Incentive Spirometry on Respiratory Muscle Strength, Chest Wall Expansion, and Lung Function in Elderly Adults.

This study aimed to investigate the effects of inspiratory muscle training (IMT) on inspiratory muscle strength, dyspnea, and quality of life (QOL) in COPD patients. A comprehensive search was undertaken on the Web of Science, Scopus, Embase, Cochrane, and PubMed databases, encompassing data published up to 31 March 2024. A meta-analysis was subsequently conducted to quantify the standardized mean difference (SMD) and 95% confidence interval (CI) for the effects of IMT in COPD patients. Sixteen studies met the inclusion criteria. IMT significantly improved inspiratory muscle strength (SMD, 0.86, p < 0.00001), dyspnea (SMD = -0.50, p < 0.00001), and QOL (SMD = 0.48, p = 0.0006). Subgroup analysis showed that <60% maximal inspiratory muscle pressure (PImax) IMT (inspiratory muscle strength, SMD = 1.22, p = 0.005; dyspnea, SMD = -0.92, p < 0.0001), IMT conducted for ≤20 min (inspiratory muscle strength, SMD = 0.97, p = 0.008; dyspnea, SMD = -0.63, p = 0.007; QOL, SMD = 1.66, p = 0.007), and IMT conducted >3 times per week (inspiratory muscle strength, SMD = 1.06, p < 0.00001; dyspnea, SMD = -0.54, p < 0.00001; QOL, SMD = 0.48, p = 0.0009) had greater effects. This meta-analysis provides clinicians with evidence supporting the recommendation that COPD patients engage in IMT at <60% PImax for more than 3 times per week, with each session lasting no more than 20 min, to improve inspiratory muscle strength, dyspnea, and QOL.

Introduction: Asthma is characterized by a narrowing and inflammation of the bronchi, with symptoms of dyspnea, fatigue and exercise limitation. Physical therapy includes inspiratory muscle training and breathing exercises, given that an increase in inspiratory muscle strength and resistance can improve the symptoms of the disease. Objective: To describe the effects of inspiratory muscle training (IMT) and breathing exercises in children with asthma. Methods: This is a systematic review of the literature using the Cochrane, PubMed Scopus e Web of Science databases. The following descriptors were used: asthma, inspiratory muscle training, breathing exercises and child in Portuguese, English and Spanish. Two independent evaluators screened studies that used breathing exercises and IMT in children with asthma. Results: Of a total of 312 titles, eight studies were included, of which six are randomized clinical trials and two are observational studies All the studies included breathing exercises, with the objective of adjusting breathing patterns and pulmonary ventilation, reducing pulmonary hyperinflation, bronchospasm and sensation of dyspnea. However, as these exercises were not performed solely, the effects of this intervention could not be verified. Two studies performed IMT and showed an increase in maximal respiratory pressure. Conclusion: Breathing exercises are widely used in clinical practice as part of the management of asthma in children; however it is not possible to measure the effects in this population. IMT seems to improve inspiratory and expiratory muscle strength, but its indication in the pediatric population is not a standard procedure.

We evaluated the effects of specific inspiratory muscle training on simulated time-trial performance in trained cyclists. Using a double-blind, placebo-controlled design, 16 male cyclists (VO 2max = 64 - 2 ml·kg -1 ·min -1 ; mean - sx ¥ ) were assigned at random to either an experimental (pressure-threshold inspiratory muscle training) or sham-training control (placebo) group. Pulmonary function, maximum dynamic inspiratory muscle function and the physiological and perceptual responses to maximal incremental cycling were assessed. Simulated time-trial performance (20 and 40 km) was quantified as the time to complete pre-set amounts of work. Pulmonary function was unchanged after the intervention, but dynamic inspiratory muscle function improved in the inspiratory muscle training group ( P h 0.05). After the intervention, the inspiratory muscle training group experienced a reduction in the perception of respiratory and peripheral effort (Borg CR10: 16 - 4% and 18 - 4% respectively; compared with placebo, P h 0.01) and completed the simulated 20 and 40 km time-trials faster than the placebo group [66 - 30 and 115 - 38 s (3.8 - 1.7% and 4.6 - 1.9%) faster respectively; P = 0.025 and 0.009]. These results support evidence that specific inspiratory muscle training attenuates the perceptual response to maximal incremental exercise. Furthermore, they provide evidence of performance enhancements in competitive cyclists after inspiratory muscle training.

BackgroundThe effect of inspiratory muscle training (IMT) applied along with function in Hypertension (HT) patients is uncertain. In this study, it was to determine the effectiveness of functional IMT (F-IMT) on functional lower and upper exercise capacity, mobility, peripheral and respiratory muscle strength, blood pressure, fatigue, physical activity, and quality of life (HRQoL) in HT patients.MethodsProspective, randomized controlled, assessor-blinded, parallel three-armed trial. Forty-five patients with HT were divided into F-IMT group (IMT with 50% maximal inspiratory pressure (MIP)/4 weeks + exercise and IMT with 50% MIP/4 weeks, n = 15), IMT group (MIP 50%, n = 15) and control group (CG, breathing exercises, n = 15). 6-min walking test (6-MWT), 6-min pegboard ring test (6PBRT), 1-min sit to stand test (1STS), mobility, peripheral muscle strength, MIP, maximal expiratory pressure (MEP), systolic& diastolic blood pressure (SBP, DBP), fatigue, physical activity, and HRQoL were evaluated before and after 8 weeks of training.ResultsIncreases in 6-MWT were higher in F-IMT (p < 0.001). 6PBRT, 1STS, quadriceps femoris strength were improved and SBP reduced in F-IMT and IMT than CG (p < 0.001). Mobility, handgrip, HRQoL, and physical activity level increased within groups (p < 0.05). MIP increased within F-IMT and IMT; MEP, fatigue, DBP improved only within F-IMT (p < 0.05).ConclusionsF-IMT is more effective in enhancing exercise capacity, reducing fatigue and DBP, and improving MEP. Both IMT and F-IMT show similar benefits for upper extremity exercise capacity, quadriceps femoris strength, SBP, and MIP. Mobility, HRQoL, and physical activity levels are increased with F-IMT, IMT, and breathing exercises.Trial registrationClinicalTrials.gov Identifier: NCT06343246 (03/29/2024).

Evidence to date strongly suggests that poor inspiratory muscle performance is associated with dyspnea, poor exercise tolerance and poor functional status in patients with heart failure (HF). A growing body of literature has examined the effects of inspiratory muscle training (IMT) in HF patients with the majority of studies reporting favorable effects on several of the above limitations and a substantial number of related deficiencies due to inadequate inspiration and inspiratory muscle strength and endurance. The domains and manifestations of HF, which were significantly improved by IMT in one or more of the 18 out of 19 studies of IMT, included dyspnea, quality of life, balance, peripheral muscle strength and blood flow, peripheral muscle sympathetic nervous activity, heart rate, respiratory rate, peak VO2, 6-min walk test distance, ventilation, VE/VCO2 slope, oxygen uptake efficiency, circulatory power, recovery oxygen kinetics and several indices of cardiac performance. This paper will also review the available IMT literature with a focus on methods of IMT and clinical outcomes. Key differences between available IMT methods will be highlighted with a goal to improve IMT efforts and decrease the pathophysiological manifestations of heart disease and HF.

To determine the effects of inspiratory muscle training (IMT) alone on inspiratory muscle strength and endurance, pulmonary function, pulmonary complications, and length of hospital stay in patients undergoing coronary artery bypass graft surgery (CABG). We conducted a literature search across databases (Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily; Ovid Embase; Ovid Cochrane Central Register of Controlled Trials; Ovid Cochrane Database of Systematic Reviews; and Scopus) from inception to December 2021. The eligibility criteria were randomized controlled trials that investigated the effects of IMT versus usual care or sham IMT in patients undergoing CABG. A total of 12 randomized clinical trials with 918 patients were included in the meta-analysis. Postoperative IMT was associated with improved maximal inspiratory pressure (MIP), maximum inspiratory pressure (PImax), and six-minute walking test (6MWT) and with a decrease in length of hospital stay (LOS). For preoperative IMT, there was statistical significance between intervention and MIP, PImax, forced expiratory volume in one second (FEV1), forced vital capacity (FVC), postoperative pulmonary complications (PPCs), and LOS. Pre- and postoperative IMT resulted in improvements in MIP. Isolated IMT in patients who underwent CABG improved their inspiratory muscle strength and endurance, pulmonary function, and 6MWT and helped decrease postoperative pulmonary complications and the length of hospital stay.