Inspiratory Muscle Strength Training Research Articles

FEASIBILITY AND ACCEPTABILITY OF INSPIRATORY MUSCLE STRENGTH TRAINING AMONG OLDER ADULTS IN MYSORE, INDIA

Abstract Hypertension, a major risk for cardiovascular and cerebrovascular diseases, affects 1.3 billion globally and 229 million in India. While exercise has shown to lower blood pressure, 40% of older Indians report inadequate physical activity. Inspiratory Muscle Strength Training (IMST), a novel breathing exercise, shows promise for controlling hypertension, but little is known about its acceptability among older Indian adults. This study examined feasibility and acceptability of IMST in older adults with hypertension in Mysore, India. Between November-2022 and January-2023, 31 non-smoking adults aged 65 - 80 years, with a blood pressure □140/90 mm Hg were enrolled in a 6-week interventional study after informed-consent. Participants used a Power-breathe Plus breath trainer for 30 breaths a day, 5 days a week, for 6-weeks, weekly increasing resistance to a maximum of 30% of their Maximum Inspiratory Pressure. Participants underwent medical assessment, interviewer-administered survey to collect data on demographics, depression, cognition, physical performance, pulmonary function and acceptability, at baseline and post-intervention. Univariate analysis was conducted. Of 31 participants, 20% were male and 55% were on antihypertensive. Four participants discontinued by week two. Post-intervention, 22% had □10 mm Hg decrease in systolic- pressure and 37% □10 mm Hg decrease in diastolic- pressure. About 59% showed improvement in depression screening scores, 40% had improved cognitive scores and 48% reported improved physical-performance scores; 80% reported IMST was useful and 90% reported device was user-friendly; 45% reported improvements in breathlessness and exercise-tolerance. IMST was acceptable, feasible and safe as a hypertension intervention for older adults in Mysore, India.

Terapi Non Farmakologi untuk Pasien Hipertensi

This research aims to find out non-pharmacological measures to reduce blood pressure that can be carried out in the emergency room. The method used is a systematic review using the keywords Disinfectant Stethoscope via Scopus, Sage, Pubmed, and ScienceDirect. Inclusion criteria: full text (abstract, introduction, methods, results, discussion, and conclusions). The research results showed that from analyzing nine articles of non-pharmacological measures for hypertensive patients, namely Buteyko breathing, Bee-Humming Breathing Exercise, Phramari Pranayama, Aerobics, green tea extract (GT) and endurance training (RT), Inspiratory Muscle Strength Training, Aerobic exercise and stretching. In conclusion, Buteyko and bhramari pranayama are non-pharmacological measures that do not require much time. According to the author, they can be applied in the emergency room.
 Keywords: Hypertension, non-pharmacological therapy

A hypotensive protocol of inspiratory muscle strength training: Systematic review and meta-analysis with trial sequential analysis.

The aim of this study was to evaluate the hypotensive effect and optimal protocol of inspiratory muscle resistance training (IMST). Randomized controlled trials using IMST to lower blood pressure (BP) were retrieved from 12 databases as of July 2022. A meta-analysis of BP and heart rate variability (HRV) was performed and a trial sequence analysis was performed using trial sequential analysis (TSA) software. Twelve articles (n=386 participants) from five countries were included, with a mean quality score of 5.83. IMST achieved significant results in reducing systolic, diastolic, and mean arterial pressure (-7.93 [-12.08, -3.78]; -3.80 [-6.08, -1.53]; -4.90 [-13.76, 3.96]). Furthermore, TSA has shown that the findings for systolic and diastolic BP are conclusive. Finally, considerable variation remained between studies when analyzing HRV. The overall hypotensive effect of IMST was demonstrated by the TSA and was well tolerated in different populations. Of these, two interventions, high resistance or low resistance combined with slow breathing, showed the best efficacy under an 8-week exercise intervention. In addition, the process of lowering BP by modulating sympathetic vagal activity has not been further confirmed in this study. Future long-term interventions, especially those over 3months, are needed to observe the prolonged antihypertensive effects and modulatory mechanisms; controlling for variables such as respiratory rate and executing more rigorous studies to further explore antihypertensive options.

Acute upper and lower limb hemodynamic responses during single sessions of low- versus high-intensity inspiratory muscle strength training.

Inspiratory muscle strength training (IMST) has shown potential to improve both respiratory and cardiovascular function in health and disease. Less is known about acute hemodynamic responses to a single IMST session, therefore we assessed upper and lower limb blood flow via Doppler ultrasound in the brachial and popliteal arteries, respectively. Mean, anterograde, and retrograde blood flow (BF) and shear rate (SR) were assessed relative to baseline during low-intensity (15% maximal inspiratory pressure - PImax) and high-intensity (75% PImax) IMST. During low-intensity IMST, popliteal BF and SR were reduced by ∼10%, and brachial BF and SR were reduced by ∼40%. During high-intensity IMST, popliteal BF and SR were reduced by ∼20%, and brachial BF and SR were reduced by ∼35%. BF and SR responses were not statistically different between low-intensity and high-intensity training for either blood vessel (P > 0.05). In addition, anterograde BF and SR were significantly decreased in the brachial artery for both low-intensity and high-intensity training (P < 0.05), but not the popliteal artery (P > 0.05). Finally, during IMST retrograde BF and SR were significantly increased in both the upper and lower limbs during low-intensity and high-intensity training (P < 0.05). These data provide novel insight into the acute BF and SR responses to a single bout of IMST and may enhance our understanding of the mechanism(s) by which IMST imparts its beneficial chronic effects on cardiovascular function.NEW & NOTEWORTHY Herein, we demonstrate for the first time that upper and lower limb blood flow and shear rate patterns are altered during a single bout of IMST, at low- and high-intensity training. Specifically, anterograde blood flow and shear rate are significantly reduced in the brachial artery, whereas retrograde blood flow is significantly elevated in both the brachial and popliteal arteries. These findings provide insight into the vascular impact of IMST, which may inform future mechanistic studies.

Piloting Res-ET: A Remote Inspiratory Muscle Strength Training Intervention On Young Stroke Survivors

Piloting Res-ET: A Remote Inspiratory Muscle Strength Training Intervention On Young Stroke Survivors

A randomised controlled trial of prehabilitation in patients undergoing elective cardiac surgery.

The feasibility, safety and efficacy of prehabilitation in adult patients awaiting elective cardiac surgery are unknown. A total of 180 participants undergoing elective cardiac surgery were allocated randomly to receive either standard pre-operative care or prehabilitation, consisting of pre-operative exercise and inspiratory muscle training. The primary outcome was change in six-minute walk test distance from baseline to pre-operative assessment. Secondary outcomes included change in inspiratory muscle strength (maximal inspiratory pressure); sarcopenia (handgrip strength); quality of life and compliance. Safety outcomes were pre-specified surgical and pulmonary complications and adverse events. All outcomes were assessed at baseline; at pre-operative assessment; and 6 and 12 weeks following surgery. Mean (SD) age was 64.7 (10.2) years; 33/180 (18%) were women. In total, 65/91 (71.4%) participants who were allocated to prehabilitation attended at least four of eight supervised in-hospital exercise classes; participants aged > 50 years were more likely than younger participants to attend (odds ratio (95%CI) of 4.6 (1.0-25.1)). Six-minute walk test was not significantly different between groups (mean difference (95%CI) -7.8 m (-30.6-15.0), p = 0.503) in the intention-to-treat analysis. Subgroup analyses based on tests for interaction indicated improvements in six-minute walk test distance were larger amongst sarcopenic patients in the prehabilitation group (p = 0.004). Change in maximal inspiratory pressure from baseline to all time-points was significantly greater in the prehabilitation group, with the greatest mean difference (95%CI) observed 12 weeks after surgery (10.6 cmH2 O (4.6-16.6) cmH2 O, p < 0.001). There were no differences in handgrip strength or quality of life up to 12 weeks after surgery. There was no significant difference in postoperative mortality (one death in each group), surgical or pulmonary complications. Of 71 pre-operative adverse events, six (8.5%) were related to prehabilitation. The combination of exercise and inspiratory muscle training in a prehabilitation intervention before cardiac surgery was not superior to standard care in improving functional exercise capacity measured by six-minute walk test distance pre-operatively. Future trials should target patients living with sarcopenia and include inspiratory muscle strength training.

A short course of high-resistance, low-volume breathing exercise extends respiratory endurance and blunts cardiovascular responsiveness to constant load respiratory testing in healthy young adults

Our objective was to evaluate the effects of 6-weeks high-resistance, low-volume inspiratory muscle strength training (IMST) on respiratory endurance, blood pressure (BP) and heart rate (HR) responsiveness to high respiratory workloads. Ten healthy young adults completed two constant-load resistive breathing tests to exhaustion (Tlim) (target pressure =65 % maximal inspiratory pressure [PImax]; duty cycle = 0.7; breathing frequency matched to eupnea) separated by 6-weeks high-resistance (75 % maximal inspiratory pressure, PImax), low-volume (30 inspiratory efforts/day, 5 days/week) IMST. Throughout resistive breathing trials we measured beat-to-beat changes in BP and HR, mouth pressure, inspiratory muscle work and perceived exertion. POST resistive breathing tests revealed significant gains in endurance (PRE: 362.0 ± 46.6 s vs. POST: 663.8 ± 110.3 s, p = 0.003) and increases in respiratory muscle work (PRE: −9445 ± 1562 mmHg.s vs. POST: −16648 ± 3761 mmHg.s, p = 0.069). Conversely, systolic and diastolic BP responses, HR and ratings of perceived exertion all declined. Consistent with previous observations, 6 weeks high resistance, low volume IMST lowered casual resting SBP (p = 0.002), DBP (p = 0.007) and mean arterial pressure (p = 0.001) and improved static inspiratory pressure. High resistance, low volume inspiratory muscle strength training extends respiratory endurance and attenuates BP responsiveness in healthy, recreationally-active young adults. The outcomes have implications for improved athletic performance and for attaining and/or maintaining cardiorespiratory fitness.

A multi-trial, retrospective analysis of the antihypertensive effects of high-resistance, low-volume inspiratory muscle strength training.

Above-normal blood pressure (BP) is a primary risk factor for cardiovascular diseases. In a retrospective analysis of five pilot trials, we assessed the BP-lowering effects of high-resistance inspiratory muscle strength training (IMST) in adults aged 18-82 years and the impact of IMST on maximal inspiratory pressure (PIMAX), a gauge of inspiratory muscle strength and independent disease risk factor. Participants were randomized to high-resistance IMST (75% PIMAX) or low-resistance sham (15% PIMAX) training (30 breaths/day, 5-7 days/wk, 6 wk). IMST (n = 67) reduced systolic BP (SBP) by 9 ± 6 mmHg (P < 0.01) and diastolic BP (DBP) by 4 ± 4 mmHg (P < 0.01). IMST-related reductions in SBP and DBP emerged by week 2 of training (-4 ± 8 mmHg and -3 ± 6 mmHg; P ≤ 0.01, respectively) and continued across the 6-wk intervention. SBP and DBP were unchanged with sham training (n = 61, all P > 0.05). Select subject characteristics slightly modified the impact of IMST on BP. Greater reductions in SBP were associated with older age (β = -0.07 ± 0.03; P = 0.04) and greater reductions in DBP associated with medication-naïve BP (β = -3 ± 1; P = 0.02) and higher initial DBP (β = -0.12 ± 0.05; P = 0.04). PIMAX increased with high-resistance IMST and low-resistance sham training, with a greater increase from high-resistance IMST (+20 ± 17 vs. +6 ± 14 cmH2O; P < 0.01). Gains in PIMAX had a modest inverse relation with age (β = -0.20 ± 0.09; P = 0.03) and baseline PIMAX (β = -0.15 ± 0.07; P = 0.04) but not to reductions in SBP or DBP. These compiled findings from multiple independent trials provide the strongest evidence to date that high-resistance IMST evokes clinically significant reductions in SBP and DBP, and increases in PIMAX, in adult men and women.NEW & NOTEWORTHY In young-to-older adult men and women, 6 wk of high-resistance inspiratory muscle strength training lowers casual systolic and diastolic blood pressure by 9 mmHg and 4 mmHg, respectively, with initial reductions observed by week 2 of training. Given blood pressure outcomes with the intervention were only slightly altered by subject baseline characteristics (i.e., age, blood pressure medication, and health status), inspiratory muscle strength training is effective in lowering blood pressure in a broad range of adults.

Abstract P070: Vascular Conditioning Exercise Acutely Enhances Endothelial Function In Young Adults

Introduction: Vascular conditioning exercise (VCE), otherwise known as high-resistance inspiratory muscle strength training, is a potent non-pharmacological therapy to reduce blood pressure. When performed daily for 6 weeks, systolic blood pressure is reduced by ~6-10 mmHg on average, in part, by increasing nitric oxide-mediated endothelial dependent dilation (EDD). While the adaptations to long-term VCE have been described, the acute effects of VCE that may mediate the long-term vascular adaptations have not been thoroughly investigated. Hypothesis: We assessed the hypothesis that a single bout of VCE would increase EDD for at least 40 minutes after exercise completion, while arterial stiffness would not be affected. Methods: Nitric oxide-mediated EDD and ischemia-induced maximal shear rate were assessed with brachial artery flow-mediated dilation, and arterial stiffness was assessed via carotid-femoral pulse wave velocity. Assessments were performed before, 10 minutes after, and 40 minutes after a single bout of VCE (5 sets of 6 breaths at 50% of maximal inspiratory pressure with 1-minute rest intervals) or a time-matched rest interval in nine young adults (22.3 ± 2.6 years; 3 male, 6 female) using a randomized crossover design, with at least 48 hours between visits. Results: All values are mean difference ± SD. There were no differences between interventions in EDD at baseline (0.73 ± 3.7%; p =0.569). EDD was significantly higher 10 minutes post-VCE, relative to the rest intervention (3.28 ± 3.37%; p = 0.019), but there were no differences at 40 minutes post-intervention (0.01 ± 4.46%; p =0.992). Further, there were no differences in maximal shear rate between measurements (all p -values &gt;0.05), indicating the changes in EDD were not due to a modified hyperaemic response. Lastly, there were no differences in arterial stiffness (Baseline: 0.22 ± 0.75 m/s; Post-10: 0.26 ± 0.51 m/s; Post-40: 0.27 ± 0.33 m/s; all p -values &gt;0.05). Conclusions: A single bout of VCE transiently enhances EDD in healthy young adults, although this effect disappears within 40 minutes of exercise completion. This acute functional response to VCE can partially explain the large improvements in EDD that are seen in response to daily VCE performance over longer periods.

Inspiratory muscle strength training for lowering blood pressure and improving endothelial function in postmenopausal women: comparison with "standard of care" aerobic exercise.

Background: High blood pressure (BP), particularly systolic BP (SBP), is the major modifiable risk factor for cardiovascular diseases and related disorders of aging. SBP increases markedly with aging in women such that the prevalence of above-normal SBP (i.e., ≥120 mmHg) in postmenopausal women exceeds rates in age-matched men. This increase in SBP is associated with vascular endothelial dysfunction, mediated by excessive reactive oxygen species-induced oxidative stress and consequent reductions in nitric oxide bioavailability. Moderate-intensity aerobic exercise is a recommended lifestyle strategy for reducing SBP. However, adherence to aerobic exercise guidelines among postmenopausal women is low (<30%) and aerobic exercise does not consistently enhance endothelial function in estrogen-deficient postmenopausal women. High-resistance inspiratory muscle strength training (IMST) is a time-efficient, adherable lifestyle intervention that involves inhaling against resistance through a handheld device (30 breaths/day). Here, we present the protocol for a randomized controlled trial investigating the efficacy of 3 months of high-resistance IMST compared to guideline-based, “standard-of-care” aerobic exercise training for decreasing SBP and improving endothelial function in estrogen-deficient postmenopausal women with above-normal SBP (120–159 mmHg) at baseline (ClinicalTrials.gov Identifier: NCT05000515). Methods: A randomized, single-blind, parallel-group design clinical trial will be conducted in 72 (36/group) estrogen-deficient postmenopausal women with above-normal SBP. Participants will complete baseline testing and then be randomized to either 3 months of high-resistance IMST (30 breaths/day, 6 days/week, 75% maximal inspiratory pressure) or moderate-intensity aerobic exercise training (brisk walking 25 min/day, 6 days/week, 40–60% heart rate reserve). Outcome measures will be assessed after 3 months of either intervention. Following end-intervention testing, participants will abstain from their assigned intervention for 6 weeks, after which BP and endothelial function will be assessed to evaluate the potential persistent effects of the intervention on the primary and secondary outcomes. Discussion: This study is designed to compare the effectiveness of time-efficient, high-resistance IMST to guideline-based aerobic exercise training for lowering SBP and improving endothelial function, and interrogating potential mechanisms of action, in estrogen-deficient postmenopausal women. Clinical Trial Registration: ClinicalTrials.gov, Identifier: NCT05000515.

Limb Hemodynamic Responses to a Single Bout of Inspiratory Muscle Strength Training

BackgroundInspiratory muscle strength training (IMST) has been shown to bring about improvements in respiratory muscle strength and reductions in blood pressure after 6 weeks of daily high intensity training. However, there has been little investigation into the effects of IMST on limb blood flow, and it is unclear how hemodynamics are altered within a single bout of training.PurposeTo investigate the acute effects of one session of either low or high intensity IMST on blood flow in the upper and lower limbs.MethodsParticipants (n=7, 57% female) aged 20 to 47 years completed two randomized laboratory visits wherein resting blood flow was measured via duplex Doppler ultrasound at the left brachial and popliteal arteries. Following baseline measures, participants' maximal inspiratory pressure (PImax) was measured using a PowerBreathe K3 device. Participants performed one session (30 breaths) of IMST at either 15% or 75% of their PImax, and blood flow was measured again at each artery for five breaths during the final ten breaths of the training. At their second visit, subjects performed whichever training level had yet to be completed and blood flow was assessed as described above.ResultsMean blood flow at the brachial artery appeared reduced during both 15% (p=0.070) and 75% training (p=0.078), which may be attributed to a significant increase in retrograde blood flow in both cases (p=0.014 and p=0.037, respectively). This increase in retrograde blood flow tended to be greater during the 75% training (p=0.066). Popliteal artery blood flow showed similar trends to brachial artery blood flow.ConclusionsWhile IMST appears to reduce brachial artery mean blood flow during a single training session, this may be due to alterations in retrograde blood flow, which tended to increase in an intensity‐dependent manner. Further investigation into the chronic hemodynamic effects of IMST is warranted.

High‐intensity, low‐volume inspiratory muscle strength training blunts the cardiovascular response to constant load respiratory testing

Previous studies indicate inspiratory muscle strength training (IMST) may attenuate blood pressure (BP) and heart rate (HR) responsiveness to sustained respiratory muscle work. However, these previous studies used a less vigorous IMST intervention and did not have subjects gauge perception of respiratory effort. Our objective in this study was to evaluate the effects of 6 weeks high intensity (75% maximum inspiratory pressure), low volume (5 sets of 6 breaths/day) IMST on BP and HR responses to a resistive breathing trial (RBT) to exhaustion (target pressure = 65% of maximal inspiratory pressure or PImax; duty cycle = 0.7; breathing frequency matched to eupnea). We recruited 10 (7M; 3F) healthy young adults to complete two RBT, pre‐ and then again post‐, 6 weeks IMST. Throughout the RBT we assessed beat‐to‐beat changes in BP and HR, inspiratory pressure, respiratory muscle work (mmHg.s) and recorded participant ratings of perceived exertion (RPE) via the Borg scale. We report significant IMST‐related improvements in endurance time (PRE: 362.0 ±46.6s vs. POST: 663.8 ±110.3s, p=0.003) and respiratory muscle work (PRE: ‐9445 ±1562mmHg.s vs. POST: ‐16648 ±3761mmHg.s, p=0.069). Remarkably, despite significant gains in work and endurance, the latter stages of the post RBT were characterized by a reduced cardiovascular responsiveness (i.e., SBP, DBP and HR) and lower RPE, consistent with a blunting of the metaboreflex.

High‐Resistance Inspiratory Muscle Strength Training‐Associated Increases in Exercise Tolerance in Midlife/Older Adults are Related to Circulating Acylcarnitines

BackgroundAge‐related declines in cardiorespiratory fitness (CRF) and exercise tolerance are major independent risk factors for cardiovascular diseases and mortality in midlife/older adults (ML/O; ≥50 years). Aerobic exercise is a well‐established strategy to improve CRF and exercise tolerance; however, adherence to time‐intensive physical activity (PA) guidelines is poor. High‐resistance inspiratory muscle strength training (IMST; 30 breaths/day against resistance, ~5 min/day) is a time‐efficient, highly adherable form of physical training but the effects of high‐resistance IMST on CRF and exercise tolerance in ML/O adults are unknown. We investigated if high‐resistance IMST would increase CRF and exercise tolerance and, if so, whether the improvements would be related to changes in circulating metabolites.MethodsThirty‐five ML/O adults performed 6 weeks of high‐resistance IMST (75% maximal inspiratory pressure [PIMAX], n=17, 9F/8M) or Sham training (15% PIMAX, n=18, 8F/10M). Peak oxygen uptake (VO2peak) was determined with an incremental treadmill exercise test to exhaustion (modified Balke protocol). Exercise tolerance was defined as treadmill time to exhaustion (TTE). Metabolic pathways modulated by high‐resistance IMST were assessed using mass spectrometry‐based plasma metabolomics.ResultsAdherence was high to both IMST and Sham training (IMST=94% of training sessions completed; Sham=90%). Body weight, body mass index (BMI), and leisure time PA levels remained stable in both groups across the intervention (all p&gt;0.05). VO2peak was unchanged after 6 weeks of either high‐resistance IMST (pre=27.7±1.2 ml/kg/min, post=27.9±1.2 ml/kg/min; p=0.75) or Sham training (pre=27.2±1.7 ml/kg/min, post=26.7±1.6 ml/kg/min; p=0.20). However, high‐resistance IMST increased TTE by 12%, with no change after Sham (IMST: pre=540±42 sec, post=606±33 sec; Sham: pre=562±39 sec, post=553±44 sec; group*time: p=0.03). TTE increases were related to changes in 18 metabolites (all p&lt;0.05), predominantly plasma acylcarnitines, which play key roles in energy production and fatty acid metabolism. Indeed, of the 19 carnitines measured, 11 were positively associated with TTE change post‐IMST. The strongest relations to TTE were seen with acyl‐C14:1 (R2=0.57; p&lt;0.01), acyl‐C10 (R2=0.54; p&lt;0.01), and acyl‐C12 (R2=0.52; p=0.01). These relations were not seen in the Sham group (all p&gt;0.05).ConclusionsIn ML/O adults, high‐resistance IMST does not increase CRF, but does improve TTE independent of changes in body weight, BMI, or PA. Improved TTE was related to changes in circulating metabolites, particularly increases in plasma acylcarnitines. These preliminary findings suggest 5 min/day of high‐resistance IMST is a promising, highly adherable mode of physical training that increases exercise tolerance and modulates metabolic pathways in ML/O adults.

A comparison of the effects of inspiratory muscle strength and endurance training on exercise capacity, respiratory muscle strength and endurance, and quality of life in pacemaker patients with heart failure: A randomized study

BackgroundStudies have widely investigated the effects of inspiratory muscle strength training in patients with heart failure (HF). The effects of inspiratory muscle strength or endurance training on outcomes in patients with pacemakers have not been adequately studied. ObjectivesThe aim was to compare the effects of inspiratory muscle strength and endurance training on exercise capacity, quality of life (QoL), peripheral and respiratory muscle strength, respiratory muscle endurance, pulmonary function, dyspnea, fatigue, and physical activity levels in pacemaker patients with HF. MethodsA randomized, controlled, double-blind study was conducted. Fourteen pacemaker patients with HF received inspiratory muscle strength training (IMST) at 50% of maximal inspiratory pressure (MIP), and 18 patients received endurance training (IMET) at 30% of MIP 7 days/8 weeks. Exercise capacity [6 min. walking test (6MWT) and the Incremental Shuttle Walking Test (ISWT)], pulmonary function, respiratory muscle strength [MIP, maximal expiratory pressure (MEP)], endurance, peripheral muscle strength, dyspnea, fatigue, QoL, and physical activity level were evaluated before and after. ResultsDemographic characteristics were similar in IMST (3F/11M, 56.92 ± 7.61y, EF: 25%, ICD/CRT:11/3) and IMET (4F/14M, 56 ± 10.77y, EF: 30%, ICD/CRT:16/2) groups (p > 0.05). Significant improvements were present in MIP, MEP, respiratory muscle endurance, peripheral muscle strength, 6MWT and ISWT walking distances, dyspnea, QoL, physical activity level, fatigue scores within groups (p ≤ 0.05). However, there were no significant differences between the groups (p > 0.05). There were no significant improvements in FEV1%, FVC%, FEV1/FVC%, and FEF25-75 within and between the groups (p > 0.05). ConclusionsInspiratory muscle strength and endurance training similarly improves respiratory and peripheral muscle strength, exercise capacity, QoL, physical activity level, and decreases dyspnea and fatigue and are safe and effective in pacemaker patients with HF. Trial registrationwww.ClinicalTrials.gov; study number: NCT03501355.

Translational Potential of High-Resistance Inspiratory Muscle Strength Training.

Age-associated cardiovascular (CV) dysfunction increases the risk for CV diseases. Aerobic exercise training can improve CV function, but only a minority of adults meet aerobic exercise guidelines. High-resistance inspiratory muscle strength training is a time-efficient lifestyle intervention that may promote adherence and improve CV function. However, further investigation is needed to translate inspiratory muscle strength training into the public health domain.

Effect of Moderate- or High-Intensity Inspiratory Muscle Strength Training on Maximal Inspiratory Mouth Pressure and Swimming Performance in Highly Trained Competitive Swimmers.

Inspiratory muscle strength training (IMST) can improve exercise performance. Increased maximal inspiratory mouth pressure (MIP) could be beneficial for swimmers to enhance their performance. This study aimed to clarify the effect of high-intensity IMST for 6weeks on MIP and swimming performance in highly trained competitive swimmers. Thirty male highly trained competitive swimmers were assigned to high-intensity IMST (HI; n = 10), moderate-intensity IMST (MOD; n = 10), and control (n = 10) groups. The 6-week IMST intervention comprised twice daily sessions for 6d/wk at inspiratory pressure threshold loads equivalent to 75% MIP (HI) and 50% MIP (MOD). Before and after the intervention, MIP and swimming performance were assessed. Swimming performance was evaluated in free and controlled frequency breathing 100-m freestyle swimming time trials in a 25-m pool. For controlled frequency breathing, participants took 1 breath every 6 strokes. The MIP values after 2 and 6 weeks of IMST in the HI and MOD groups were significantly higher than those before IMST (P = .0001). The magnitudes of the MIP increases after 6 weeks of IMST did not differ between the HI (13.4% [8.7%]) and MOD (13.1% [10.1%]) groups (P = .44). The 100-m freestyle swimming times under the controlled frequency condition were significantly shorter after IMST than those before IMST in both the HI (P = .046) and MOD (P = .042) groups. Inspiratory pressure threshold load equivalent to 50% MIP could be sufficient to improve MIP and swimming performance under the controlled frequency breathing condition in highly trained competitive swimmers.

Six Months of Inspiratory Muscle Training to Lower Blood Pressure and Improve Endothelial Function in Middle-Aged and Older Adults With Above-Normal Blood Pressure and Obstructive Sleep Apnea: Protocol for the CHART Clinical Trial.

Background: Cardiovascular disease is a major global health concern and prevalence is high in adults with obstructive sleep apnea (OSA). Lowering blood pressure (BP) can greatly reduce cardiovascular disease risk and physical activity is routinely prescribed to achieve this goal. Unfortunately, many adults with OSA suffer from fatigue, daytime sleepiness, and exercise intolerance—due to poor sleep quality and nocturnal hypoxemia—and have difficulty initiating and maintaining an exercise program. High-resistance inspiratory muscle strength training (IMST) is a simple, time-efficient breathing exercise consistently reported to reduce BP in small, selective groups of both healthy and at-risk adults. Herein we present the study protocol for a randomized clinical trial to determine the long-term efficacy of IMST performed regularly for 24 weeks in middle-aged and older adults with OSA. The primary outcome is casual systolic BP. Secondary outcomes are 24-h systolic BP and circulating plasma norepinephrine concentration. Other outcomes include vascular endothelial function (endothelial-dependent and -independent dilation), aortic stiffness, casual and 24-h diastolic BP, and the influence of circulating factors on endothelial cell nitric oxide and reactive oxygen species production. Overall, this trial will establish efficacy of high-resistance IMST for lowering BP and improving cardiovascular health in middle-aged and older adults with OSA.Methods: This is a single-site, double-blind, randomized clinical trial. A minimum of 92 and maximum of 122 male and female adults aged 50–80 years with OSA and above-normal BP will be enrolled. After completion of baseline assessments, subjects will be randomized in a 1:1 ratio to participate in either high-resistance or sham (low-resistance) control IMST, performed at home, 5 min/day, 5 days/week, for 24 weeks. Repeat assessments will be taken after the 24-week intervention, and after 4 and 12 weeks of free living.Discussion: This study is designed to assess the effects of 24 weeks of IMST on BP and vascular function. The results will characterize the extent to which IMST can reduce BP when performed over longer periods (i.e., 6 months) than have been assessed previously. Additionally, this study will help to determine underlying mechanisms driving IMST-induced BP reductions that have been reported previously.Clinical Trial Registration: This trial is registered with ClinicalTrials.gov (Registration Number: NCT04932447; Date of registration June 21, 2021).

Treatment effectiveness for Vocal Cord Dysfunction in adults and adolescents: A systematic review.

To determine whether treatment effectiveness can be established for a range of vocal cord dysfunction (VCD) interventions in adolescents and adults. A systematic review of the literature and risk of bias appraisal was completed using the Joanna Briggs Institute Critical Appraisal Tools. Data were qualitatively synthesized in the broad intervention groups of glottic airway and respiratory retraining, pharmacological therapies, airway device therapies and psychological therapies. Nine electronic databases, two clinical trial registries and the grey literature were searched from inception to September 2021 for articles on VCD interventions or equivalent terms. Studies were included if they were randomized controlled trials, non-randomized controlled trials, quasi-experimental pre- and post-test studies and within-subject repeated measure designs, participants were 13years or older, VCD was diagnosed using laryngoscopy or CT larynx, VCD intervention was provided and outcome measures reported on VCD symptoms. The search yielded no randomized controlled trials. There were 17 quasi-experimental studies that met the eligibility criteria, and these studies reported on glottic airway and respiratory retraining, botulinum toxin injections, inspiratory muscle strength training and amitriptyline; all were associated with VCD symptom reduction. In addition, 2 within-subject repeated measure studies reported inspiratory muscle strength training and respiratory retraining to be effective in reducing symptoms in participants with exertional VCD. The included studies were reported in full-text publications (11) and conference proceedings (8). There was a high risk of bias and low quality of evidence across all intervention areas. Glottic airway and respiratory retraining, botulinum toxin injections, low-dose amitriptyline and inspiratory muscle strength training devices have been associated with symptom reduction in adults and adolescents with vocal cord dysfunction. Limited objective data exist to support the effectiveness of these interventions, and robust controlled trials are needed in this area. Systematic Review Registration: CRD42018092274 (PROSPERO).

Time-efficient, high-resistance inspiratory muscle strength training for cardiovascular aging.

Cardiovascular diseases (CVD) remain the leading cause of death in developed and developing societies and aging is the primary risk factor for CVD. Much of the increased risk of CVD in midlife/older adults (i.e., adults aged 50years and older) is due to increases in blood pressure, vascular endothelial dysfunction and stiffening of the large elastic arteries. Aerobic exercise training is an effective lifestyle intervention to improve CV function and decrease CVD risk with aging. However, <40% of midlife/older adults meet guidelines for aerobic exercise, due to time availability-related barriers and other obstacles to adherence. Therefore, there is a need for new lifestyle interventions that not only improve CV function with aging but also promote adherence. High-resistance inspiratory muscle strength training (IMST) is an emerging, time-efficient (5min/day) lifestyle intervention. Early research suggests high-resistance IMST may promote adherence, lower blood pressure and potentially improve vascular endothelial function. However, additional investigation will be required to more definitively establish high-resistance IMST as a healthy lifestyle intervention for CV aging. This review will summarize the current evidence on high-resistance IMST for improving CV function with aging and will identify key research gaps and future directions.

Time-Efficient Inspiratory Muscle Strength Training Lowers Blood Pressure and Improves Endothelial Function, NO Bioavailability, and Oxidative Stress in Midlife/Older Adults With Above-Normal Blood Pressure.

BackgroundHigh‐resistance inspiratory muscle strength training (IMST) is a novel, time‐efficient physical training modality.Methods and ResultsWe performed a double‐blind, randomized, sham‐controlled trial to investigate whether 6 weeks of IMST (30 breaths/day, 6 days/week) improves blood pressure, endothelial function, and arterial stiffness in midlife/older adults (aged 50–79 years) with systolic blood pressure ≥120 mm Hg, while also investigating potential mechanisms and long‐lasting effects. Thirty‐six participants completed high‐resistance IMST (75% maximal inspiratory pressure, n=18) or low‐resistance sham training (15% maximal inspiratory pressure, n=18). IMST was safe, well tolerated, and had excellent adherence (≈95% of training sessions completed). Casual systolic blood pressure decreased from 135±2 mm Hg to 126±3 mm Hg (P<0.01) with IMST, which was ≈75% sustained 6 weeks after IMST (P<0.01), whereas IMST modestly decreased casual diastolic blood pressure (79±2 mm Hg to 77±2 mm Hg, P=0.03); blood pressure was unaffected by sham training (all P>0.05). Twenty‐four hour systolic blood pressure was lower after IMST versus sham training (P=0.01). Brachial artery flow‐mediated dilation improved ≈45% with IMST (P<0.01) but was unchanged with sham training (P=0.73). Human umbilical vein endothelial cells cultured with subject serum sampled after versus before IMST exhibited increased NO bioavailability, greater endothelial NO synthase activation, and lower reactive oxygen species bioactivity (P<0.05). IMST decreased C‐reactive protein (P=0.05) and altered select circulating metabolites (targeted plasma metabolomics) associated with cardiovascular function. Neither IMST nor sham training influenced arterial stiffness (P>0.05).ConclusionsHigh‐resistance IMST is a safe, highly adherable lifestyle intervention for improving blood pressure and endothelial function in midlife/older adults with above‐normal initial systolic blood pressure.RegistrationURL: https://www.clinicaltrials.gov; Unique identifier: NCT03266510.