The Association of Cigarette Smoking on Exercise Capacity and Skeletal Muscle Function in Taiwan Adult Smokers

Background and purpose: Cigarette smoking would post threats to physical health. Even though studies suggested that long-term cigarette smoking would lead to cardiovascular diseases, pulmonary diseases, or even cancer development, the smoking population all around the world was still common. Before progressing into the disease stage, cigarette smokers might have presented decreasing exercise capacity, skeletal muscle function, and cardiac autonomic function as early signs of physiological function decline. The purposes of this study are (1) to investigate the difference in exercise capacity, skeletal muscle function, and cardiac autonomic function between smokers and never smokers, and (2) to test the hypothesis that cigarette smoking is an independent factor associated with exercise capacity.

Methods: This is a cross-sectional observational study. This study will invite 150 participants from community in Taipei City. The body composition will be analyzed by bioelectrical impedance analysis, and resting heart rate variability will be evaluated by the heart rate variability monitor. Besides, grip strength, exhale carbon monoxide concentration, pulmonary function test, respiratory muscle performance will be measured. Moreover, subject will have to fill up the Fagerström Test for Nicotine Dependence and Seven-Day Physical Activity Recall Questionnaire. Last will be the cardiopulmonary exercise testing. Statistical analyses will be performed by statistical software for social sciences (SPSS) statistical package v.21.0 for Windows. (IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp.) Between-group comparisons of exercise capacity, skeletal muscle function and heart rate variability parameters will be performed using independent Student's t-test. Pearson's correlation coefficient will be used to test the correlations between outcome parameters. Stepwise regression analysis will be used to examine the independent association between smoking and exercise capacity after controlling for confounders. The α level will be set at 0.05. The results of this study would provide the early effects of cigarette smoking on physical function, and highlight the importance of early detection and intervention.