Power Spectral Analysis of Heart Rate Variability in Heavy Workers
Keywords:Power spectral analysis (PSA), cardiac autonomic nervous activities (CANA), heavy workers, sedentary workers
Introduction: Sedentary life style deteriorates Cardiac autonomic nervous activities (CANA). Regular physical activity may improve CANA.
Objective: Heart rate variability (HRV) was analyzed by Power Spectral method in heavy workers to find out the influence of regular physical activity on CANA.
Methods: This cross sectional study was carried out on 30 heavy workers aged 28-50 years (study group), at the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU) over a period of 1 year. Simultaneously 30 sedentary workers of high socioeconomic status (group C) were studied to observe the influence of socioeconomic condition on heart rate variability (HRV). For comparison thirty age, sex, body mass index (BMI) and socioeconomic condition matched apparently healthy sedentary subjects (control) were also studied. The study subjects were selected from rickshaw-pullers living in the slum area nearby the university and the controls from fourth class employee of the university. Group C were selected from the doctors serving in the university and some from personal contacts. Total power, low frequency (LF) power, high frequency (HF) power, LF nu (neutralized unit), HF nu and LF/HF ratio were assessed and analyzed by a Polygraph. For statistical analysis, one way analysis of variance (ANOVA), Independent-samples t-test and Pearson's correlation coefficient tests were done.
Results: Total power, HF power and HF nu were significantly (p<0.001) higher and LF power, LF nu and LF/HF ratio were significantly (p<0.001) lower in heavy workers than those of sedentary subjects. Total power and HF nu showed positive correlations and LF nu and LF/HF ratio showed negative correlation with duration of works per day but all these correlations were statistically non-significant.
Conclusion: Regular physical activity improves cardiac autonomic nerve function status with a cardiac parasympathetic predominance.
Key words: Power spectral analysis (PSA); cardiac autonomic nervous activities (CANA); heavy workers; sedentary workers
JAFMC Bangladesh. Vol 7, No 1 (June) 2011; 15-19