EFFECTS OF AGE, HEART-RATE, GENDER, TOBACCO AND ALCOHOL INGESTION ON R-R INTERVAL VARIABILITY IN HUMAN ECG

To evaluate the possibly confounding effects of age, gender, heart rate, tobacco and alcohol ingestion on the coefficient of variation of the electrocardiographic R-R interval (CV(RR)), ECGs in the supine posture were obtained in 68 healthy men and 33 healthy women. The C-CV(RSA) and C-CV(MWSA) (two component CVs reflecting respiratory sinus arrhythmia and Mayer wave related sinus arrhythmia, respectively) were computed in each subject from component spectral powers using autoregressive spectral and component analyses. Results of multiple regression analysis indicated that age was inversely related to CV(RR), C-CV(RSA) and C-CV(MWSA) in both sexes. Heart rate was positively related to C-CV(MWSA) in males. However, no significant difference in the CV(RR), C-CV(RSA) or C-CV(MWSA) was found between males and females. The C-CV(MWSA) was not correlated with the C-CV(RSA) in either males or females. These data indicate that the CV(RR), C-CV(RSA) and C-CV(MWSA) are affected by age and partly by heart rate; gender, moderate smoking or drinking habits might not strongly influence autonomic nervous system function. On the other hand, the C-CV(RSA) in the supine posture appears to be independent of the C-CV(MWSA). The positive relationship observed between the C-CV(MWSA) and heart rate suggests that the C-CV(MWSA) may be associated with sympathetic activity.