RELATIONSHIP BETWEEN PHYSICAL WORK LOAD AND OBESITY IN CHILEAN FOUNDRY WORKERS

摘要

Studies carried out in Chilean copper foundries reveal that workers are exposed to very high levels of radiant heat. Although mechanization has reduced the time of exposure, there are still many jobs with high physiological demands due to a combination of manual work and heat exposure. At the same time, it has been observed that Chilean miners are increasing their body fat and that overweight is putting an additional load which may result in very high work load. The present study was carried out with the following aims: To determine the average work load during foundry work To establish the effect of work capacity and body composition on the work load. The physiological work load was obtained from cardiac frequency recorded minute by minute using a telemetric unit (Polar Vantage) in a sample of 27 workers. Aerobic capacity was obtained from submaximal tests carried out in a bicycle ergometer (Monark, Sweden). Body composition, in terms of body fat and fat free mass, was estimated after measuring biceps, triceps, subscapular and suprailiac skinfolds according to a technique validated for Chilean workers. The results showed that the average aerobic capacity was low (2.3 l min-1) as compared to other groups of Chilean workers. This was more noticeable when expressed by kilogram body weight (28.8 ml min-1 kg-1), mainly due to the excess fat; 89% of the sample had overweight or were obese. A stepwise regression procedure showed that the average cardiovascular load at work was negatively correlated with aerobic capacity and positively correlated with globe temperature (R=0.86; R2=0.74; p 0.001). The results of this study only confirm the trend to obesity of Chilean mining workers and the effect that overweight has on their physical fitness. Manual work can be particularly critical when they perform their work exposed to heat. One chance would be to redesign work methods to reduce the time of exposure. The education of the workers, with materials specially prepared, seems a good alternative.