ACOUSTIC AND SPIROMETRIC INDICES OF FORCED EXPIRATION NOISE IN THE CONDITIONS OF 5-DAY DRY IMMERSION
Dynamic studies of forced expiration (FE) indices involved 7 normal males aged 21 to 25 participating in a 5-d experiment with dry immersion (DI). FE spirometry was conducted simultaneously with registration of tracheal noise with the help of a microphone. Indices included acoustic duration of tracheal noise ( Та ), forced lung capacity (FLC), FE volume per a second (FEV1), peak expiratory rate (PER) and time to reach ( Т <sub>PER</sub> ) before DI, on DI days 1 and 4, and next day after completion. PER showed a significant decrease by 8.4 % on DI day-1 and rose by 8.9 % on DI day-4, though remaining below pre-DI values. Throughout the experiment, FLC and FEV1 did not change on the average. There was a noticeable increase of Та by 17 % after DI which may suggest strengthening of respiratory resistance and invites further investigation. A moderate negative correlation was stated between TA and the Gensler index (r = -0.63), whereas correlation with the other spirometric indices was weak or absent.