[Sleep disturbance caused by noise]

This contribution is a state-of-the-art of recent knowledge regarding effects from environmental noise on sleep and proposes acoustic thresholds likely to help public authorities in setting up regulations. It recalls physiological sleep aspects and the cyclic organization of the various stages; then it examines noise effects, principally those arising from road traffic, planes and trains. Such effects are firstly considered as changes in sleep organization during night. It is noted that laboratory and home experiments lead to the same conclusions: duration of deep sleep is appreciably reduced for younger people, while the dream phase is disturbed for older people. These disturbances are associated with an average energetic level Leq. Then partial effects are investigated, either electro-encephalographic or cardiac; these effects are more especially associated with isolated acoustic phenomena and determined from the noise peak level. Other variables, e.g. back noise, phenomena number per period, interval between two noises, have an effect on probability of a local phenomenon which can be connected to a given peak level. The conclusion is that two acoustic values must be retained for considering sleep disturbances: the first one is the energetic level inside the room, with a comfort threshold of 35 dB(A) by night, and the second one is the lowest peak level which should not exceed 50 dB(A).