Longitudinal Ultrasound Assessment of Diaphragmatic and Respiratory Muscle Function Following Respiratory Muscle Training in Frail Older Adults

N/ANot Yet RecruitingNCT07258615

Universidad Francisco de Vitoria30 enrolled

Overview

This study aims to evaluate the effects of an 8-week inspiratory muscle training program on diaphragmatic and respiratory muscle function in frail older adults aged 80 years and above. Frailty is associated with reduced physical capacity, impaired respiratory performance, and a higher risk of disability. Inspiratory muscle training is a simple, low-cost intervention that may improve breathing function, strength, and overall health in very old adults, but evidence in this age group remains limited. Participants will be randomly assigned to one of two groups: a high-load inspiratory muscle training group or a low-load sham training group. Both groups will use a threshold device and perform 30 breaths once per day, five days per week, for eight weeks. The experimental group will train with progressively increasing resistance (50% to 80% of maximal inspiratory pressure), while the sham group will use a minimal and non-progressive load (15% of maximal inspiratory pressure). All sessions will be supervised and monitored for safety. The main goal of the study is to determine whether inspiratory muscle training improves maximal inspiratory pressure (MIP), an established measure of global inspiratory muscle strength. Secondary outcomes include ultrasound-based assessments of diaphragmatic structure and function, such as diaphragm thickness, contractile fraction, diaphragmatic excursion, inspiratory time, and inspiratory velocity during deep breathing and sniff maneuvers. These measurements will help clarify the physiological adaptations produced by inspiratory muscle training in this population. Assessments will be performed before the intervention, immediately after the 8-week program, and again at one and three months after the end of the intervention to examine both immediate and short-term effects. This study may contribute valuable evidence regarding the safety, feasibility, and clinical benefits of inspiratory muscle training in frail very old adults, supporting its potential implementation in rehabilitation and geriatric care.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

Interventions

Inspiratory Muscle TrainingDEVICE

Participants perform 30 breaths once daily, 5 days per week for 8 weeks using a threshold inspiratory muscle training device. The load begins at 50% of maximal inspiratory pressure (MIP) and increases by 5 cmH₂O weekly up to 80% of MIP. Sessions are supervised and oxygen saturation and heart rate are monitored.

Sham Inspiratory Muscle TrainingDEVICE

Participants use the same device and schedule as the experimental group (30 breaths once daily, 5 days per week for 8 weeks) but with a constant load of 15% of maximal inspiratory pressure (MIP), with no weekly progression. This mimics the procedure while providing minimal physiological stimulus. Supervision and monitoring are identical to the experimental arm.

Eligibility

Sex: ALLMin age: 80 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Adults aged 80 years or older. * Clinical diagnosis of frailty, defined by a Short Physical Performance Battery (SPPB) score \< 9. * Ability to stand and walk with or without assistive devices. * Ability to understand and follow instructions for inspiratory muscle training. * Stable medical condition for at least 3 months prior to enrollment. * Capacity to provide informed consent or availability of a legal representative. Exclusion Criteria: * Acute or unstable cardiovascular, respiratory, or metabolic conditions. * Severe cognitive impairment that prevents understanding the procedures. * Diagnosis of neuromuscular diseases affecting respiratory muscles (e.g., ALS, myopathies). * Severe or uncontrolled hypertension (≥180/110 mmHg). * Recent thoracic or abdominal surgery (\<3 months). * Severe musculoskeletal disorders limiting participation in training. * History of recurrent syncope, severe dizziness, or intolerance to respiratory maneuvers. * Any condition judged by the research team to compromise safety or participation.

Outcomes

Primary Outcomes

Maximal Inspiratory Pressure (MIP)

Maximal Inspiratory Pressure (MIP) will be measured using a calibrated handheld manometer following standardized respiratory assessment guidelines. Participants will be instructed to perform a maximal inspiratory effort from residual volume through the mouthpiece with their nose occluded. At least three maneuvers will be recorded, ensuring less than 10% variability between attempts. The highest reproducible value (cmH₂O) will be used for analysis. This measure reflects global inspiratory muscle strength and is widely validated in older and frail populations.