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Estimation of the exertion requirements of coal mining work.

The work requirements of coal mining work were estimated by studying a group of 12 underground coal miners. A two level (rest, 300 kg X m/min) test was performed to estimate the linear relationship between each subject's heart rate and oxygen consumption. Then, heart rates were recorded during coal mining work with a Holter type recorder. From these data, the distributions of oxygen consumptions during work were estimated, allowing characterization of the range of exertion throughout the work day. The average median estimated oxygen consumption was 3.3 METS, the average 70th percentile was 4.3 METS, and the average 90th percentile was 6.3 METS. These results should be considered when assessing an individual's occupational fitness.