Cardiac strain of confectionery worker in relation to heat exposure during regular work shift

CONTEXT: In India, a wide variety of occupations are performed in adverse indoor working environment. Work physiological studies in these jobs are scanty as compared to investigations done on more arduous outdoor occupations. AIMS AND OBJECTIVES: Physiological strain of workers engaged in sweet making activities was assessed in terms of cardiac strain indices in relation to heat stress. SETTING AND DESIGN: 33 full-time workers from eastern India were compared for cardiac strain profile obtained during summer and winter during their regular work shift. A comparison was also done in between younger (n=12) and older (n=16) subjects. MATERIALS AND METHODS: Working heart rate (WHR) was recorded continuously during work. The pulse deceleration index (PDI) was obtained from recovery heart rate (RHR). Net cardiac cost (NCC) and relative cardiac cost (RCC) were the main indices used to evaluate physical strain. Thermal stress assessed from wet bulb globe temperature (WBGT). STATISTICAL ANALYSIS: Students’ t-test and Wilcoxon signed rank paired tests were used for comparing physiological responses. Values were considered significant when P < 0.05. RESULTS: Work load was significantly higher in summer for all workers. RCC of younger workers in winter and summer ranged between 18% and 26%. This was significantly lower as compared to the RCC of older workers which was 27% in winter and 30% in summer. The physiological workload appeared to be moderate in nature. The WBGT index was above the recommended range in summer for both the groups. Older workers showed a no recovery pattern in terms of recovery pulse that indicated toward a cumulative stress which may be attributed to a combined effect of heat and work in summer and extra amount of work performed in winter season. CONCLUSION: The physical workload is aggravated with various ergonomic stressors present in the work place. An ergonomic intervention has been indicated as further scope of this study.