Related factors of low back pain (LBP) among school personnel were investigated. We designed a cross-sectional study employing questionnaires, which included a Japanese version of the Job Content Questionnaire. Subjects consisted of 3306 male and 3184 female school personnel in all public schools and kindergartens operated by Nagoya City, Japan. Prevalence of LBP in each work category was compared to that in general teachers of each gender after adjusting for age. Male teachers at schools for the handicapped and in classrooms for the handicapped showed significantly higher LBP prevalence. Among female participants, teachers at schools for the handicapped, physical education teachers, kindergarten personnel and school nurses displayed higher LBP prevalence. In work categories which demonstrated high LBP prevalence, low social support and low job satisfaction were related to LBP of school nurses despite low physical loads. High job demand and physical loads correlated to LBP in kindergarten personnel.

We investigated the effects of laughing and weeping induced by watching comedy and tragedy videos on mood and autonomic nervous function. Ten healthy female subjects volunteered for the experiment. Chest electrocardiogram and respiration curve were recorded before, after, and during watching a comedy or a tragedy video. We also asked them to fill out profiles of mood states (POMS) to evaluate their mood states while watching videos. Autonomic nervous function was estimated by spectral analysis of heart rate variability (HRV). All subjects more or less laughed and wept while watching comedy and tragedy videos, respectively. Anger-hostility score of the POMS decreased and vigor score increased significantly after watching comedy videos, while depression-dejection score increased significantly after watching tragedy ones. Although both contents tended to increase a low to high frequency component ratio (LF/HF ratio) of HRV, the time course of responses was different. The LF/HF ratio which reflects cardiac sympathovagal balance increased immediately after they started watching comedy videos, and returned to the basal level right after they stopped watching, whereas the LF/HF ratio increased gradually to a lesser extent while watching tragedy videos. In contrast, the high-frequency component which reflects cardiac parasympathetic nerve activity gradually decreased while watching both videos but did not return to the basal level after watching tragedy ones. These results suggest that laughing has strong but transient effects on the autonomic nervous system, while weeping or feeling sad has moderate but sustained effects on it.

We investigated the effects of vital exhaustion (VE) on cardiac autonomic functions in relation to working conditions such as overtime and frequent business trips, and to lifestyles such as smoking on 52 healthy middle-aged male workers. VE was evaluated by an abbreviated Maastricht Vital Exhaustion Questionnaire. Cardiac autonomic function at supine rest was assessed by spectral analysis of heart rate variability in an annual health checkup. The mean amplitude of the high frequency (HF: 0.15-0.4 Hz) component was lower in the high-VE group, whereas no significant difference in the ratio of the low frequency (LF: 0.04-0.15 Hz) component power to HF power (the LF/HF ratio) was observed among VE groups. There were significant interactive effects of VE and smoking on HF amplitude, and of VE and frequent business trips on the LF/HF ratio. VE symptoms were related to the suppression of the cardiac para-sympathetic nervous function at rest in middle-aged male workers, but not to the alteration in sympathovagal balance. Smoking and overwork such as frequent business trips may amplify the autonomic dysfunction in relation to VE among workers with a pronounced feeling of VE.

Blood Pressure and Heart Rate Variability in Taxi Drivers on Long Duty Schedules: Fumio KObayashi, et al. Department of Health and Psychosocial Medicine, Aichi Medical University School of Medicine Objective To clarify the mechanisms of excessive risk of cardiovascular disease among taxi drivers, the effects of taxi driving with long work hours on taxi drivers' blood pressure and heart rate variability were examined. Methods We measured the physical activity level, ambulatory blood pressure, and Holter ECG in 34 healthy middleaged male taxi drivers over one work day and the two following non‐work days. The subjects worked for a 24‐h period starting at 07:00, then rested from work for 48 h. Ambulatory blood pressure was recorded automatically at 30‐min intervals over the 72‐h period. Holter ECG records were also kept for the 72 h, and temporal changes in the R‐R interval were analyzed by the complex demodulation method (COM). The amplitude of the high frequency (HF) components (central frequency 0.30 Hz), and the ratio of lowfrequency components (central frequency 0.09 Hz) to high‐frequency components (LlH) was calculated. Results Blood pressure during the work day was significantly higher than that during the non‐work days, with a stronger effect in the hypertensive subjects. There were no significant overall differences in heart rate variability between the work day and the non‐work days, but the temporal patterns of HF and UH on the work day revealed a potent effect of reversed‐phased circadian rhythm for work at night. Conclusions Long duty taxi driving raises blood pressure and may increase cardiovascular risk as a result. The conflict between the circadian rhythms of autonomic nervous activity and work activity at night may also result in increased risk.

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