The purpose of this study was to investigate the acute effects of cigarette smoking on heart rate, vagal-cardiac nerve activity at rest and during a short isometric work (Experiment 1) and peak anaerobic power test of riding a bicycle (Experiment 2), and of 8-19 days of abstinence from cigarette on the cardiorespiratory capacity (VO₂, VE, HR, LA and vagal-cardiac nerve activity during the submaximal and maximal running on a treadmill and at rest (Experiment 3), in healthy adult men. Measurements of vagal-cardiac nerve activity were made at rest and during exercise by use of the technique of spectral analysis of heart rate variability. Smoking provoked the following changes; Heart rate at rest increased 1-22 beats/min. After bicycling peak anaerobic power test, heart rate increasing before cigarette smoking were due to decreasing the level of the vagal-cardiac nerve activity, and heart rate increasing after cigarette smoking were reversely due to increasing the level of the sympathetic nerve activity. Abstinence from cigarette smoking provoked the increase of vagal-cardiac nerve activity of levels and consequently decrease of heart rate during and after treadmill running at almost all stages. However, VO₂, VE and LA during submaximal and maximal running were different from subject.
　So we would like to suggest that smoking acutely increased the heart rate at rest, as a result of reducing baseline level of vagal-cardiac nerve activity. After the shortest bicycling anaerobic power test, heart rate increased as a result of reducing baseline of vagal-cardiac nerve activity before smoking, and heart rate increasing after smoking were reversely due to increasing sympathetic nerve activity. The abstinence (8-19 days) from smoking reduced the heart rate and increased the vagal-cardiac nerve activity during maximal and submaximal exercise and at rest.

DESCENTE SPORTS SCIENCE Vol.22/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE