The measurement of inspiratory muscle strength is achieved by static measures of respiratory maximum pressures (inspiratory- MIP and expiratory- MEP) and is an important tool for determining the existence and prognosis of neuromuscular and lung disorders. <b>Aim:</b> To develop predictive equations of inspiratory pressure Maximum and Maximum Expiratory Pressure for healthy people sedentary and active. <b>Materials and Methods:</b> Participants were 177 sedentary healthy and active, aged 20 and 80 years. The volunteers were selected according to the following criteria: a BMI between 18.0 and 29.5 kg / m2 and no history of smoking. Individuals with a history of respiratory or cardiovascular disease were excluded, as well as individuals with any neuromuscular disease that prevented the tests. Maximal respiratory pressures were determined according to a standardized protocol. <b>Results:</b> Two regression models were adjusted: 1 (age- gender) and 2 (gender and physical activity). For the model MEP, there was an increase in the R² 15.91% to 26.18%, indicating that with age and activity can be explained 26.18% of the variability of MEP. For the model of MIP, the R² went from 6.05% to 16.46%, indicating that with age and activity can be explained 16.46% of the variability of MIP. <b>Conclusion:</b> Was checked with the adjusted models, there was a considerable gain in the predictive quality of the models for MEP and MIP add Physical Activity.