Heart rate response to industrial work at different outdoor temperatures with or without temperature control system...

Different outdoor temperatures, the association between indoor temperature control at the workplace and working heart rates of industrial employees were evaluated. The subjects, 6,016 male and female employees in 21 industrial plants in Israel, were screened for cardiovascular risk factors between 1985-87 (The CORDIS Study). The data collected included resting heart rate, working heart rate (based on one hour ambulatory ECG), outdoor temperatures, temperature control (TC) status of the plant, workload, age and health-related habits. At outdoor temperatures below or above 22-28 degrees C, subjects working in plants with TC had lower mean working heart rate HR (-2 bpm) than those working in plants without TC (p < 0.0004 after adjustment for confounders). No statistically significant differences in mean working HR were found between subjects working with TC (at all the outdoor temperatures) and those without TC within the outdoor temperature range 22-28 degrees C. Based on working heart rate, indoor temperature control in industrial plants appears to moderate the cardiovascular strain in working subjects during both cold and hot days.