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. Additionaiiy we aim to estimate the workioad reaiized during the maneuvers. Method: Tweive heaithy young men were evaiuated, instructed and famiiiarized 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 ( Delta HR); Valsalva index (VI); MEP index (MEPI), and the estimated workload of the maneuvers (W sub(total), W sub(isotime), W sub(total)/ Delta HR sub(total) and W sub(isotime)/ Delta HR sub(isotime)). Results: The Delta HR during the maneuvers was not influenced by the supine and sitting positions. However, the Delta HR during the VM and VI were higher (supine: 47 plus or minus x9 bpm, 2.3 plus or minus 0.2; sitting: 41 plus or minus 10 bpm, 2.0 plus or minus 0.2, respectively) than Delta HR during the MEP and MEPI values (supine: 23 plus or minus 8 bpm, 1.5 plus or minus 0.2; sitting 24 plus or minus 8 bpm, 1.6 plus or minus 0.3, respectively) (p<0.001). The estimated workload of the maneuvers was statistically different (p<0.001) between the maneuvers, except to W sub(total)/ Delta HR. Conclusions: In the studied conditions the MEP does not reproduces the HR response observed in the VM in healthy young men.Original Abstract: Contextualizagao: A medida de pressao expiratoria maxima (PEmax) possui algumas contraindicacoes, pois acredita-se que as respostas obtidas nessa medida sao similares as respostas encontradas na manobra de Valsalva (MV). Objetivos: O objetivo principal e avaliar a resposta da frequencia cardiaca (FC) durante a medida da PEmax e da MV em jovens saudaveis, em diferentes posturas, para identificar se e em qual condicao a PEmax reproduz as respostas obtidas na MV e, adicionalmente, estimar o trabalho realizado nas manobras. Metodo: Doze jovens saudaveis foram avaliados, orientados e familiarizados com as manobras. A MV foi composta por um esforgo expiratorio (40 mmHg) durante 15 segundos contra um manometro. A PEmax foi executada segundo a American Thoracic Society. Ambas as medidas foram reallzadas nas posturas supino e sentado. Para a analise da variacao da frequencia cardiaca (AFC), indice de Valsalva (IV), indice da PEmax (IPEmax) e o trabalho estimado das manobras (W sub(total), W sub(isotime), W sub(total)/ Delta FC sub(total) e W sub(isotime)/ Delta FC sub(isotime)), utilizou-se ANOVA two-way com post-hoc de Holm-Sidak (p<0,05). Resultados: A Delta FC durante as manobras nao foi influenclada pelas posturas; entretanto, durante a MV, a AFC e os valores do IV foram maiores (supino: 47 plus or minus 9 bpm, 2,3 plus or minus 0,2; sentado: 41 plus or minus 10 bpm, 2,0 plus or minus 0,2, respectivamente) do que a Delta FC e os valores de IPEmax observados durante a PEmax (supino: 23 plus or minus 8 bpm, 1,5 plus or minus 0,2; sentado 24 plus or minus 8 bpm, 1,6 plus or minus 0,3, respectivamente) (p<0,001). Os trabalhos estimados das manobras foram estatisticamente diferentes (p<0,001) entre elas, exceto para o W sub(total)/ Delta FC. Conclusoes: Nas condig oes estudadas, a PEmax nao reproduz as respostas da FC observadas durante a MV em jovens saudaveis.