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Csanády, G.A. ; Filser, J.G.

The relevance of physical activity for the kinetics of inhaled gaseous substances.

Arch. Toxicol. 74, 663-672 (2001)
DOI PMC
Open Access Green as soon as Postprint is submitted to ZB.
Inhalation is the most important route of absorption for many volatile substances. The inhaled chemical is distributed via the bloodstream into the organs and tissues. It is eliminated mainly unchanged by exhalation and also via metabolism. The blood concentration can be considered as a surrogate for the body burden of the chemical. It depends on the rate of uptake and on the rate of elimination. The rate of uptake by inhalation is determined by the blood:air partition coefficient of the gaseous compound, the actual concentration of the chemical already in the blood entering the lungs, the blood flow through the lungs, and the alveolar ventilation. The latter is greatly influenced by physical activity, which thus has a crucial impact on the rate of uptake. Consequently, the blood concentration of an inhaled chemical and the resulting alveolar retention, representing the rate of metabolism at steady-state, are dependent on the intensity of physical work. Both parameters can be calculated for steady-state conditions using simple algebraic equations, if one assumes that the rate of metabolic elimination is limited by the blood flow through the metabolizing organs. This assumption is valid for many rapidly metabolized inhaled gases and vapours at low concentrations present under workplace conditions. The derived equations give the theoretical background for the observations presented from a series of experimental studies which demonstrate that physical activity can be a major determinant of the toxicokinetics of inhaled compounds. Practical examples illustrate the procedure. We conclude that workplace-related physical activity should be taken into account for compounds with blood:air partition coefficients above 6 in the determination of occupational limit concentrations in air.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords toxicokinetics; inhalation; physical activity; alveolar retention; body burden; volatile compounds; PHYSIOLOGICALLY BASED PHARMACOKINETICS; PARTITION-COEFFICIENTS; INHALATION PHARMACOKINETICS; GAS UPTAKE; ORGANIC-SOLVENTS; RISK ASSESSMENT; STEADY-STATE; VENOUS-BLOOD; N-HEXANE; EXPOSURE
ISSN (print) / ISBN 0340-5761
e-ISSN 1432-0738
Journal Archives of Toxicology
Quellenangaben Volume: 74, Issue: 11, Pages: 663-672 Article Number: , Supplement: ,
Publisher Springer
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Institute of Molecular Toxicology and Pharmacology (TOXI)