The effect of smoking on the cardiovascular autonomic functions: a cross sectional study

Smoking is a worldwide major cause of preventable morbidity and mortality. Smoking affects the cardiovascular system by several mechanisms. The present study was planned to study the effect of smoking on the cardiovascular autonomic functions among smokers.

Hundred male subjects who were in the age group of 25 to 40 years, who included 50 smokers and 50 non - smokers who formed the control group were selected for the present study. The participant subjects were selected from among the staff members, residents and the patients from the routine OPD. Prior informed written consents were obtained from them after explaining to them, the procedure and the purpose of the study tests. The Cardiovascular Autonomic Function Tests were assessed by using a CANWIN AUTONOMIC ANALYSER which was available in the department.

After applying the 'Z'-test for the difference between the two sample means, it was observed that there was a highly significant difference between the mean values of the para-sympathetic function tests among the smokers and the non - smokers (i.e. p<0.01) The Resting Heart Rate had significantly increased and the Expiration: Inspiration Ratio, the 30:15 Ratio (Response to standing) and the Valsalva Ratio had significantly decreased in the smokers as compared to those in the non - smokers. After applying the 'Z'-test for the difference between the two sample means, it was observed that there was no significant difference between the mean values of the Postural hypotension test (i.e. p>0.05) and that there was a highly significant difference between the mean values of the Sustained handgrip test in the smokers and the non - smokers (i.e. p<0.01).