A study of Autonomic functions in shift workers

A person is considered as a shift worker if the work schedule is outside the routine 9am 5pm. Shift work causes considerable disturbance of biological clock and alteration in sleep wake cycle. This alteration imposes a stress in the body causing significant disturbances in the autonomic functions. The study includes two study groups of age, sex and BMI matched 30 shift workers and 30 non- shift workers. All the 60 subjects undergo Heart Rate Variability and other autonomic function tests. The results showed significant increase in LF, LF HF, and Blood pressure raise in Isometric Hand Grip is more in shift workers suggestive of sympathetic over activity. The values of HF, 3015, EI and Valsalva ratio is reduced suggestive of parasympathetic withdrawal. Reduced mean RR interval suggests reduced Heart rate variability. Thus shift workers showed sympathetic over activity, parasympathetic withdrawal and reduced Heart Rate Variability. The changes in shift workers may due to altered circadian rhythm.