Solvent Exposure, Shiftwork, and Sleep.

The effects of different conditions of occupational exposure to organic solvents on subjective sleep quality were studied with and without shiftwork. Laboratory studies showed that four hours of daytime exposure to ethanol (400, 800 ppm) by inhalation led to blood ethanol levels below 0.01 per thousand and had marginal effects on the following night's sleep. Exposures to acetone (1,000 ppm), ethyl acetate (400 ppm), and a solvent mixture (acetone 500 ppm, ethyl acetate 200 ppm) increased the subjective depth of sleep. In a field study with eight hours of exposure, during three different work shifts, dose-response relationships between acetone concentrations during the shiftwork and the depth of sleep were found. Nevertheless, the solvent-exposed shift workers reported a reduced sleep quality, mainly in connection with daytime sleep, in comparison with non-exposed shift workers. The effects of solvent exposure during shiftwork on sleep varied with time of day of the exposure.