Short-Term Inspiratory Muscle Training Enhances Functional and Metabolic Health in Older Adults

Background: Age-related declines in respiratory muscle strength and ventilatory efficiency can impair functional capacity and metabolic health in older adults. Inspiratory muscle training (IMT) has been proposed as a practical intervention to counteract these changes, yet its systemic effects remain unclear. This study aimed to examine the effects of short-term IMT on functional capacity, diaphragm thickness, and liver tissue characteristics in healthy elderly men. Methods: Thirty community-dwelling men aged 60–80 years were randomly assigned to an IMT or control group. The IMT group performed four weeks of breathing exercises using a POWERbreathe® device at 40% of maximal inspiratory pressure, with a weekly 10% increase. Pre- and post-intervention assessments included the six-minute walk test (6MWT), diaphragm thickness and liver density via computed tomography, and quality of life (QoL; SF-12). Results: Four weeks of inspiratory muscle training significantly improved diaphragm thickness (11.7%), fatty liver density (FLD) (+16.7%), and six-minute walk performance (+5.3%), with large time × group effects favoring the IMT group. While physical quality of life showed modest, comparable improvements, mental health outcomes demonstrated a moderate, time-dependent enhancement without a significant group interaction. Conclusions: Short-term IMT improved diaphragmatic function and functional capacity in older men and was associated with favorable changes in a liver-related biomarker; however, given that only a single liver-related metric was assessed, these findings should not be interpreted as evidence of overall improvements in liver health.**背景**：老年人的呼吸肌力量与通气效率随年龄增长出现的退行性下降，可损害其功能能力与代谢健康。吸气肌肉训练（Inspiratory Muscle Training，IMT）已被提出作为对抗此类变化的实用干预手段，但其全身效应目前仍不明确。本研究旨在探讨短期吸气肌肉训练对健康老年男性的功能能力、膈肌厚度及肝组织特征的影响。 **方法**：本研究纳入30名年龄在60~80岁之间的社区居住男性，将其随机分配至吸气肌肉训练组或对照组。训练组受试者使用POWERbreathe®设备进行为期4周的呼吸训练，初始负荷为最大吸气压力的40%，每周递增10%。干预前后的评估指标包括6分钟步行试验（Six-Minute Walk Test，6MWT）、计算机断层扫描（Computed Tomography，CT）测量的膈肌厚度与肝脏密度，以及生活质量（Quality of Life，QoL；SF-12量表）。 **结果**：为期4周的吸气肌肉训练可显著提升受试者的膈肌厚度（11.7%）、脂肪肝密度（Fatty Liver Density，FLD，+16.7%）与6分钟步行成绩（+5.3%），且呈现出较大的时间×组效应，训练组的改善效果更优。尽管躯体生活质量仅出现小幅且相似的改善，但心理健康指标呈现出中等程度的、随时间变化的提升，未出现显著的组间交互作用。 **结论**：短期吸气肌肉训练可改善老年男性的膈肌功能与功能能力，且与肝脏相关生物标志物的良性变化相关；但由于仅评估了单一肝脏相关指标，本研究结果不应被解读为肝脏整体健康状况改善的证据。