Biological process

response to lowered oxygen levels

Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a stimulus reflecting a decline in the level of oxygen.

This term should be used when a decrease in oxygen levels is not considered a stress response. For a hypoxic stress response, consider instead 'response to hypoxia ; GO:0001666'.