Increased blood lead levels in runners training in urban areas.

In an attempt to examine the hypothesis of whether physical activity causes increased uptake of lead in humans, blood lead levels were measured in 231 individuals. Included in the study were subjects who lived in Northern Italy and who practiced noncompetitive running in urban areas or along the countryside. The mean values (1.25 +/- 0.27 mumol/l) measured in a group of 28 runners who trained at tracks and on roads of a large town, characterized by heavy traffic and high atmospheric lead levels, were slightly higher than those recorded in a group of 10 runners of the same town who trained mostly in a rural environment (0.99 +/- 0.29 mumol/l) and, with a striking and significant difference, in a comparable group of 182 nonrunners (0.46 +/- 0.22 mumol/l). These background figures were similar to those found in 11 runners who lived in a smaller, less polluted urban area who trained in country roads (0.40 +/- 0.11 mumol/l). Blood lead levels were correlated significantly with the intensity and frequency of the running practice and were unrelated to smoking habits.