Effects of obesity, current smoking status, and alcohol consumption on heart rate variability in male white-collar workers.

In order to examine the effects of mild to moderate obesity, moderate to heavy smoking, and moderate alcohol consumption on cardiac parasympathetic activities and systemic sympathetic activities, a cross-sectional survey was carried out in 282 healthy Japanese male white-collar workers. Their autonomic activities were assessed as amplitudes of spectral components of heart rate variability (HRV) which was measured in the annual physical examination at their work sites. Taking the effects of aging on HRV into account, the cardiac parasympathetic activity at supine rest and its response to a change in posture were reduced in mildly to moderately obese subjects with a body mass index of 21-36, whereas the sympathetic activity was not. The effects of smoking and alcohol consumption on HRV were not confirmed. The above results means that we should consider obesity as a covariate when we examine possible relationships between cardiac parasympathetic activity and other environmental factors. There is a need for further studies on the relationships among obesity, change in parasympathetic activity, and development of health problems. The dose-effect relationships between long-term smoking or alcohol consumption and chronic changes in autonomic activities also remain to be determined.