ASSESSMENT OF IMMEDIATE IMPACT OF CIGARETTE SMOKING ON CARDIAC SYMPTHOVAGAL BALANCE IN YOUNG HEALTHY ADULT

Smilee Johncy S.*, Ashwini S. and Victor Thomas V.

ABSTRACT

Cigarette smoking has detrimental effects on the cardiovascular system, particularly by compromising the control of the Autonomic Nervous System, which results in diminished cardiovascular function. The immediate influence of cigarette smoking on cardiac sympthovagal balance was not well studied. This study investigated the short-term effects of smoking on autonomic cardiac control in healthy young adult cigarette smokers aged 18 to 30 years. After smoking a cigarette, heart rate variability (HRV) readings were recorded 5, 10, and 30 minutes later. The values were compared with initial resting HRV recordings. Both the paired and unpaired t-tests were used to analyse the data. Our study, showed a statistically significant increase in Low Frequency (LF) in msec2, LF nu, and LF/HF measures at 5 and 10 minutes post-smoking, remaining slightly elevated even at 30 minutes. Conversely, Total Power, High Frequency (HF) in msec2, and HF nu showed a significant decrease during the same intervals, with lower levels persisting to a smaller extent at 30 minutes. The most pronounced changes occurred 5 to 10 minutes after smoking. Smoking cigarettes suppresses cardiac vagal modulation and causes an instantaneous rise in sympathetic activity. This results in a short-term decrease in cardiac vagal activity and an enhancement of cardiac sympathetic activity. These acute effects generally reverse approximately 30 minutes post-smoking, indicating a temporary shift in sympathovagal balance towards sympathetic dominance. Hence smoking causes autonomic dysfunction with predominantly sympathetic over activity making them more vulnerable to cardiovascular diseases.

Keywords: Cigarette smoking, Heart Rate Variability, LF/HF ratio.