RESUMO
INTRODUCTION: Respiratory muscle strength (RMS) is a determinant of vital capacity, and its decline can lead to inadequate ventilation and deficiency in the elimination of secretions from the airways. Studies analyzing RMS in older adults with Parkinson's disease (PD) and Alzheimer's disease (AD) remain scarce, making the analysis of this variable still very uncertain. The aim of this study was to analyze the RMS of older adults diagnosed with PD and AD, in relation to healthy control peers. METHODS: A cross-sectional study was conducted involving 65 older adults comprising 3 groups: PD (n = 20), AD (n = 20), and control (n = 25). The participants underwent anthropometric and cirtometric measurements associated with maximal respiratory pressures. We analyzed data using descriptive (mean and SD) and inferential statistics (1-way analysis of variance, Student t test, and Scheffé post hoc) with a level of significance of 5% (P < .05) and a CI of 95%. RESULTS: Although the anthropometric and cirtometric variables indicated similarity of values between groups (P > .05), the maximal inspiratory and expiratory pressures were considerably lower in the subjects with PD and AD (P < .01). CONCLUSIONS: The control of the anthropometric and cirtometric variables of the subjects indicates that RMS is affected by the aging process, and its decline increases in neurodegenerative conditions. This fact represents a serious risk for the development of atelectasis and other pneumo-functional complications, which must be considered in proposing of future therapies.