No Evidence That Hyperpnea-Based Respiratory Muscle Training Affects Indexes of Cardiovascular Health in Young Healthy Adults

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

BACKGROUND

Given the promising effects of inspiratory muscle training (IMT), determining the most appropriate IMT protocol will optimize the training benefits.

OBJECTIVES

The objective of this study was to determine the effects of high intensity interval-based inspiratory muscle training (H-IMT) on cardiovascular, pulmonary, physical, and psychosocial functions in patients with heart failure and reduced ejection fraction (HFrEF).

METHODS

Thirty-four patients with HFrEF were randomly assigned to the H-IMT or control group for 3 days/week, 8 weeks training period. The H-IMT group performed IMT at least 70% of the maximal inspiratory pressure, whereas the control group performed unloaded IMT. Each session occurred 7 sets with a total of 21 min consisting of 2-min training and 1-min interval. Heart rate variability (HRV), arterial stiffness, respiratory muscle strength and endurance, diaphragm thickness, quadriceps strength, functional capacity, frailty, dyspnea, fatigue, disease-specific health-related quality of life (HRQoL), and generic HRQoL were evaluated at baseline and after 8 weeks training period by blinded assessors.

RESULTS

Statistically significant between-group differences were observed in the time domain parameters of HRV, arterial stiffness, inspiratory and quadriceps muscle strength, respiratory muscle endurance, diaphragm thickness, functional capacity, frailty, dyspnea, fatigue, and disease-specific HRQoL in favor of the H-IMT group (p<0.05).

CONCLUSIONS

H-IMT is an effective protocol for improving cardiac autonomic function, arterial stiffness, inspiratory and quadriceps muscle strength, respiratory muscle endurance, diaphragm thickness, functional capacity, frailty, dyspnea, fatigue, and disease-specific quality of life in patients with HFrEF.

CLINICAL TRIAL REGISTRATION

NCT04839211.

Effects of Inspiratory Muscle Training in Patients With Pulmonary Hypertension

The study aimed to examine the effects of inspiratory muscle training (IMT) in patients with pulmonary hypertension (PH). A total of 24 patients with PH were included in the randomized controlled evaluator-blind study. IMT was performed at 40% to 60% of the maximal inspiratory pressure for 30 min/d, 7 d/wk (1 day supervised) for 8 weeks. Respiratory muscle strength, dyspnea, diaphragm thickness (DT), pulmonary functions, 24-hour ambulatory blood pressure (BP), arterial stiffness, exercise capacity, upper extremity functional exercise capacity, physical activity levels, fatigue, anxiety-depression levels, activities of daily living (ADL), and quality of life were evaluated. A total of 24 patients (treatment = 12, control = 12) completed the 8-week follow-up. There was no significant difference between the patient groups in terms of demographic and clinical characteristics (p >0.05). Considering the change between the groups in the treatment and control groups, brachial and central BP, dyspnea, respiratory muscle strength, DT in total lung capacity, knee extension muscle strength, functional exercise capacity, upper extremity functional exercise capacity, physical activity, ADL, fatigue, anxiety, and quality of life improved in favor of the IMT group (p <0.05). In conclusion, IMT has improved brachial and central BP, dyspnea, respiratory muscle strength, DT in total lung capacity, knee extension muscle strength, functional exercise capacity, upper extremity functional exercise capacity, physical activity, ADL, fatigue, anxiety, and quality of life compared with the control group. IMT is an effective method in cardiopulmonary rehabilitation for patients with PH.

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.

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 50 years 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 (5 min/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.