Blood carbon monoxide levels as a function of daily cigarette consumption and physical activity.

Carboxyhaemoglobin concentrations (COHb) have been measured in groups of individuals smoking while engaged in different activities. The three groups chosen (meat porters, office workers, and pregnant women) had finger-prick blood samples taken at about six hours into their working day. COHb was measured by the method of Commins and Lawther (1965), a method subsequently shown to have a mean error of 0-67% (SD 0 65) in the range 0-40% COHb (Lily, Cole, and Hawkins, 1972). A highly significant difference (P < 0 005) was found between the COHb