Reference values for respiratory muscle strength and maximal voluntary ventilation in the Brazilian adult population: A multicentric study

Aim To determine reference values and propose prediction equations for respiratory muscle strength, maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and endurance by means of maximal voluntary ventilation (MVV) in healthy Brazilian adults. Methods Anthropometric data, level of physical activity, pulmonary function, and respiratory muscle strength and maximal voluntary ventilation of 243 participants (111 men and 132 women) aged 20 to 80 years were assessed at three cities in the southeast and northeast region of Brazil. Results Mean maximal respiratory pressures and MVV were higher in men (MIP = 111.0 ± 28.0; MEP = 149.6 ± 40.3; MVV = 150.6 ± 35.2) than in women (MIP = 87.9 ± 17.6; MEP = 106.7 ± 25.2; MVV = 103.4 ± 23.2; all p < 0.05). Based on regression models, the following prediction equations were proposed for men: MIP = 137–0.57 (age), R2 = 0.13, standard error of estimate (SEE) = 26.11; MEP = 179.9–0.67 x (age), R2 = 0.08, SEE = 38.54; and MVV = 206.3–1.18 x (age), R2 = 0.36, SEE = 28.08. Prediction equations were also proposed for women: MIP = 107.3–0.4 x (age), R2 = 0.16, SEE = 16.10; MEP = 127.4–0.43 x (age), R2 = 0.08, SEE = 24.09; and MVV = 146.3–0.86 x (age), R2 = 0.42, SEE = 17.56. Conclusion Reference values for MIP, MEP, and MVV were determined in healthy Brazilian adults. Results from different Brazilian regions provided adequate prediction equations considering an ethnically heterogeneous population.