TY - JOUR T1 - Physiological responses to the six-minute walk test in older adults JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - p2152 AU - Victor Dourado AU - Ricardo Guerra AU - Letícia Antunes AU - Suzana Tanni AU - Irma Godoy Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/p2152.abstract N2 - Physiological responses to the six-minute walk test (6MWT) have been increasingly evaluated in patients with cardiopulmonary diseases. However, previous studies did not include healthy persons. The aim of this study was to evaluate age- and gender-related changes in physiological responses to the 6MWT and to establish a set of predictive equations for such variables. We evaluated 102 non-trained healthy older adults (48 men, aged 62±8) stratified in four age groups (40-49; 50-59; 60-69; ≥70). After familiarization, a third 6MWT was performed using a telemetric gas analyzer (k4b2) for assessing metabolic and cardiopulmonary responses as well as oxygen uptake (VO2) time constant (tau) by an exponential fitting. Lean body mass (LBM) (impedance) and handgrip strength (HGS) were measured in 81 subjects. A set of linear equations was provided for prediction of the main physiological variables. The rate of gas exchange (R), VO2/heart rate (HR), deficit-O2 and tauVO2 were not affected by sex as well as tidal volume (VT), R and VO2/HR were not affected by age. Deficit-O2 and tauVO2 presented a tendency to age-related changes (p = 0.06). Several prediction equations adjusted by sex, age, height, weight, LBM, HGS, and 6MWT showed R2 values ranging 0.114 to 0.574 (e.g. deficit-O2 and VT respectively). The best model for predicting VO2peak was adjusted by LBM and age (R2=0.435). None of the variables studied was selected as predictive factors for tauVO2. Therefore the prediction equations might provide a more appropriate frame of reference for normal physiological responses to the 6MWT in healthy older adults. Our results may be useful for better interpretation of walking performance in patients with cardiopulmonary disease. ER -