Cardiorespiratory fitness and peripheral muscle function in physically active adult smokers

Smoking may yield impairment in physical fitness. We hypothesized that adult smokers present decreased physical fitness despite a good level of physical activity in daily life (PADL). We aimed to compare the cardiorespiratory fitness (CRF) and peripheral muscle function in physically active adult smokers and non-smokers. Seventeen smokers (SG), free of lung disease, and 18 non-smokers (CG) aged 30 to 65 years were enrolled. The participants used a triaxial accelerometer for 7 days to assess PADL and those who performed l 2.5 h/wk of moderate to vigorous physical activity were excluded. Anthropometrics, body composition, spirometry, cardiopulmonary exercise testing (CPET), and isokinetic muscle function of the dominant upper and lower limb were assessed. The smoking load in the SG was 30 pack-yr and all the participants presented normal spirometry. There were no significant differences between SG and CG regarding the time spent in moderate–vigorous (5.2 ± 2.5 vs. 5.4 ± 2.0 h) and in vigorous–very vigorous PADL (0.16 ± 0.24 vs. 0.16 ± 0.23 h). The SG presented lower values of FEV 1 (88 ± 14 vs. 104 ± 12%pred.) and FVC (88 ± 15 vs. 104 ± 14%pred.). Peak V9O 2 in the CPET was significantly reduced in the SG (90 ± 12 vs. 101 ± 17%pred.). Despite the similar intensity of PADL, the SG showed increased time spent lying (7.2 ± 6.2 vs. 3.5 ± 2.4%) and tended to spend more time sitting (26 ± 9 vs. 21 ± 8%; p = 0.08). Peripheral muscle function and body composition were preserved in the SG. We may conclude that smoking affects cardiorespiratory fitness even in physically active adult smokers.