Laaddosis

Laaddosis is a theoretical construct used to describe the cumulative exposure of a system to a stressor, blending the notions of dose and load. It appears in discussions across toxicology, physiology, and systems biology as a way to quantify how repeated or prolonged exposure translates into response.

Definition and units: The laaddosis (LD) is conceived as the time-weighted exposure to a stressor, essentially a sum or integral of exposure over time. In some proposals, accumulated exposure is expressed in laaddosis units (LU). Weighting factors may be included to reflect absorption, metabolism, and individual sensitivity.

Relation to other concepts: Laaddosis overlaps with cumulative dose and allostatic load, but emphasizes the combined effect of exposure magnitude and duration. It helps illustrate how short, intense exposures and long, mild exposures can yield similar burdens over time.

Applications: Proponents discuss laaddosis in toxicology, occupational health, ecotoxicology, and environmental health to model chronic risk, guide exposure limits, and compare exposure scenarios. It is also invoked in debates about psychosocial or digital stress where repeated strain accumulates.

Reception and limitations: The term is not widely standardized in formal literature. Critics argue that laaddosis can oversimplify complex dynamics such as recovery, adaptation, and susceptibility variability. In practice, researchers typically rely on established metrics such as cumulative exposure, dose–response curves, or allostatic load indexes.

See also: cumulative dose, allostatic load, exposure assessment.