Long-term exposure to high CO2 in coal mine environment could lead to diminished exercise performance, acid-base changes and other health effects. CPET testing and blood gas analysis during the work at the head of coal mine excavation would provide an accurate estimate of true workplace-related impact on physical performance and health status.
We performed lung function testing (spirometry and single breath DlCO), blood gasses and modified Masters step test in 76 coal miners, that worked at least 10 years in a row as a head-excavation miners. CPET parameters were measured using portable metabolic analyzer. Tests were performed in duplicates: every subject underwent the same procedure out and in a coal mine –approximately 430 m under the ground level. CO2 in a coal mine was continuously monitored and mean value of was 1.21%. Paired tests were used for presentation of results.
There was no chronic acid-base disorder. pO2 of arterial blood, spirometry values and DlCO after exercise in and out of the coal mine were not significantly different. Ventilation in the coal mine was elevated with an average increase of 11%. Increase in ventilation was mainly due to increase in tidal volume. Increase in heart rate was lower during exercise and oxygen consumption was 11% less in the mine (same level of exercise). Anaerobic threshold did not differ.
No lung function of blood gas deficit was noted in tested coal miners. Exercise performance in coal mine atmosphere was not affected by increase in ventilation. Lower oxygen consumption during the same level of exercise in a coal mine could be due to more efficient skeletal muscle recruitment or unknown influence of other atmosphere conditions on sceletal muscle performance.
Physical work in a coal mine with increased CO2 levels of average 1.21% is not associated with chronic or acute respiratory and muscular changes.
Matjaz Flezar, None.