Heart rate assessment during maximal static expiratory pressure and Valsalva maneuver in healthy young men* Avaliação da frequência cardíaca à medida de pressão expiratória máxima estática e à manobra de Valsalva em jovens saudáveis

Background: The measure of the maximal expiratory pressure (MEP) has some contraindications, as it is believed that the responses obtained in this measure are similar to the Valsalva maneuver (VM). Objective: The main purpose of this study was to evaluate the heart rate responses (HR) during the MEP and the VM measures in healthy young men into different postures aiming to identify whether and in which situation the MEP reproduces the responses obtained in the VM. Additionally we aim to estimate the workload realized during the maneuvers. Method: Twelve healthy young men were evaluated, instructed and familiarized with the maneuvers. The VM was characterized by an expiratory effort (40 mmHg) against a manometer for 15 seconds. The MEP measure has been performed according to the American Thoracic Society. Both measures were performed at sitting and supine positions. ANOVA two-way with Holm-Sidak post-hoc test (p<0.05) was used to analyse the heart rate variation (∆HR); Valsalva index (VI); MEP index (MEPI), and the estimated workload of the maneuvers (Wtotal, Wisotime, Wtotal/∆HRtotal and Wisotime/∆HRisotime). Results: The ∆HR during the maneuvers was not influenced by the supine and sitting positions. However, the ∆HR during the VM and VI were higher (supine: 47±9 bpm, 2.3±0.2; sitting: 41±10 bpm, 2.0±0.2, respectively) than ∆HR during the MEP and MEPI values (supine: 23±8 bpm, 1.5±0.2; sitting 24±8 bpm, 1.6±0.3, respectively) (p<0.001). The estimated workload of the maneuvers was statistically different (p<0.001) between the maneuvers, except to Wtotal/∆HR. Conclusions: In the studied conditions the MEP does not reproduces the HR response observed in the VM in healthy young men.