Chen Chien-Liang, Tang Jing-Shia, Li Ping-Chia, Chou Pi-Ling
Department of Physical Therapy, I-Shou University Kaohsiung, Taiwan.
Department of Nursing, Chung-Hwa University of Medical Technology Tainan, Taiwan ; Institute of Allied Health Sciences, National Cheng Kung University Tainan, Taiwan.
Front Physiol. 2015 Dec 10;6:376. doi: 10.3389/fphys.2015.00376. eCollection 2015.
This study compared the immediate effects of smoking on cardiorespiratory responses to dynamic arm and leg exercises.
This randomized crossover study recruited 14 college students. Each participant underwent two sets of arm-cranking (AC) and leg-cycling (LC) exercise tests. The testing sequences of the control trial (participants refrained from smoking for 8 h before testing) and the experimental trial (participants smoked two cigarettes immediately before testing) were randomly chosen. We observed immediate changes in pulmonary function and heart rate variability after smoking and before the exercise test. The participants then underwent graded exercise tests of their arms and legs until reaching exhaustion. We compared the peak work achieved and time to exhaustion during the exercise tests with various cardiorespiratory indices [i.e., heart rate, oxygen consumption (VO2), minute ventilation (VE)]. The differences between the smoking and control trials were calculated using paired t-tests. For the exercise test periods, VO2, heart rate, and VE values were calculated at every 10% increment of the maximal effort time. The main effects of the time and trial, as well as their trial-by-time (4 × 10) interaction effects on the outcome measures, were investigated using repeated measure ANOVA with trend analysis.
5 min after smoking, the participants exhibited reduced forced vital capacities and forced expiratory volumes in the first second (P < 0.05), in addition to elevated resting heart rates (P < 0.001). The high-frequency, low-frequency, and the total power of the heart rate variability were also reduced (P < 0.05) at rest. For the exercise test periods, smoking reduced the time to exhaustion (P = 0.005) and the ventilatory threshold (P < 0.05) in the LC tests, whereas no significant effects were observed in the AC tests. A trend analysis revealed a significant trial-by-time interaction effect for heart rate, VO2, and VE during the graded exercise test (all P < 0.001). Lower VO2 and VE levels were exhibited in the exercise response of the smoking trial than in those of the control LC trials, whereas no discernable inter-trial difference was observed in the AC trials. Moreover, the differences in heart rate and VE response between the LC and AC exercises were significantly smaller after the participants smoked.
This study verified that smoking significantly decreased performance and cardiorespiratory responses to leg exercises. However, the negative effects of smoking on arm exercise performance were not as pronounced.
本研究比较了吸烟对动态手臂和腿部运动心肺反应的即时影响。
这项随机交叉研究招募了14名大学生。每位参与者都进行了两组手臂曲柄运动（AC）和腿部骑行运动（LC）测试。对照试验（参与者在测试前8小时不吸烟）和试验性试验（参与者在测试前立即吸两支烟）的测试顺序是随机选择的。我们观察了吸烟后和运动测试前肺功能和心率变异性的即时变化。然后，参与者进行了手臂和腿部的分级运动测试，直到筋疲力尽。我们将运动测试期间达到的峰值工作量和运动至疲劳的时间与各种心肺指标[即心率、耗氧量（VO2）、分钟通气量（VE）]进行了比较。吸烟试验和对照试验之间的差异采用配对t检验计算。在运动测试期间，VO2、心率和VE值在最大努力时间每增加10%时进行计算。使用重复测量方差分析和趋势分析研究时间和试验的主要影响，以及它们对结果测量的试验×时间（4×10）交互作用。
吸烟5分钟后，参与者除静息心率升高（P<0.001）外，第一秒用力肺活量和用力呼气量也降低（P<0.05）。静息时心率变异性的高频、低频和总功率也降低（P<0.05）。在运动测试期间，吸烟缩短了LC测试中的运动至疲劳时间（P = 0.005）和通气阈值（P<0.05），而在AC测试中未观察到显著影响。趋势分析显示，在分级运动测试期间，心率、VO2和VE存在显著的试验×时间交互作用（均P<0.001）。吸烟试验的运动反应中VO2和VE水平低于对照LC试验，而在AC试验中未观察到明显的试验间差异。此外，参与者吸烟后，LC和AC运动之间心率和VE反应的差异显著减小。
本研究证实，吸烟显著降低了腿部运动的表现和心肺反应。然而，吸烟对手臂运动表现的负面影响并不那么明显。
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