Assessment of cardiac strain amongst underground coal carriers—A case study in India

A study of cardiac cost assessment among 12 healthy underground coal carriers was conducted whose average age was 35.6±8.3 years. Before going down the mine heart rate at rest was measured which had been 64±5 beats min −1. During their course of loading activity the average working heart rate was found to be 124±9.8 beats min −1. The maximum heart rate were estimated (184±8.2 beats min −1) and it was observed that during the period of activity they had been quite above their recommended levels of cardiac stresses. The speed with and without load was calculated and the overall speed of loading was reported to be 4.3±0.6 km h −1 with a mean lead distance 23.1±7.6 m. Since the degree of stress during their course of action is related to their efficient activity, an attempt was made to evaluate the job nature and relative cardiac strains throughout the period of observations. Hot environmental situations that could impose a great cardiac stress to the workers were also reported.