Cardiac workload of dressers in underground manual coal mines

Abstract

Introduction: Occupational disorders invite absenteeism amongst the miners. Though rapid technological advancement has happened, yet assessment of cardiac workload was largely ignored in underground coal mines in India. Methods: Physiological stress was evaluated in terms of working heart rate, net cardiac cost and relative cardiac cost. Heart rate was measured during their course of work by heart rate monitor at the coal face. Recovery heart rates and environmental heat load were also assessed. Results: Heart rate was found to be 117 and 122 beats/min respectively in first and second spell. NCC (49.7 and 54.8 beats /min) and RCC (47% and 52%) exhibit significant variations between spells, whereas rate of recovery had been very poor amongst the workers who regularly exceeded recommended levels of cardiac strain indices. The nature of work depicted it as a heavy job although recovery trend categorizes it heavier than that. ET and WBGT were above the recommended limits as per the guidelines of WHO and ACGIH. Conclusions: High physiological demand of the job with towering heat stress was found to hinder the recovery process and may cause deleterious impacts on the workers. Ergonomic interventions were highly felt towards job organization and up gradation of environmental conditions.

Cardiac strain comparison between workers with normal weight and overweight in the hot humid weather of the Persian Gulf region

“…After 60 minutes of heat exposure, the subject was made to stop work and sit on a footstool in the same work station, and the heart rate was measured at the last 30 seconds of each minute of the recovery period, that is, from 30 seconds to one minute (p 1 ) after stop of work, and from 2.5-3 minutes (p 3 ) and 4.5-5 minutes (p 5 ). [ 7 11 ] Assessment of heart rate recovery and reaching the normal rate was done by comparing P 1 and P 3 ; thus, if P 1 -P 3 <10 and P 3 < 90 beats per minute (bpm), the heart rate reduction pattern was normal; if P 1 -P 3 >10 and P 3 < 90 bpm, the duration of returning the heart rate to the normal pattern was long and conditions might require further analysis; and if P 1 -P 3 <10 and P 3 > 90 bpm, it would show that returning to normal heart rate had not happened, and this ‘no-recovery’ pattern indicated too much strain. [ 8 12 ] To estimate the physical activities, the Persian version of the Rating Perceived Exertion of the Eston-Parfitt was used.…”