Twenty-one world experts on sleep medicine and epidemiologists met to review the effects on health ofdisturbed sleep. Invited experts reviewed the state of the art in sleep parameters, sleep medicine and,long-term effects on health of disturbed sleep in order to define a position on the secondary and long-term effects of noise on sleep for adults, children and other risk groups. This report gives definitions ofnormal sleep, of indicators of disturbance (arousals, awakenings, sleep deficiency and fragmentation);it describes the main sleep pathologies and disorders and recommends that when evaluating the healthimpact of chronic long-term sleep disturbance caused by noise exposure, a useful model is the healthimpact of chronic insomnia.