Night noise guidelines for Europe - WHO/Europe - World Health ...

EFFECTS ON SLEEP 55
Motility
0.042
0.040
0.038
0.036
0.034
Fig. 3.4
Increase in mean motility (body movements during
sleep). Converted from inside relation with [3]
0.032
42 2 62 2 82
L
night, outside, facade
The increase in m night is 22% over the baseline motility (0.03 on average) if indoor
L night,inside increases from 0 (absence of aircraft noise) to 35 dB(A) (living close to a runway).
This increase is independent of age, although the absolute level varies.
Other chronic effects like the use of sleeping pills, changes in BP and changes in levels
of stress hormones are discussed in the next chapter.
3.3 CONCLUSIONS
During sleep the auditory system remains fully functional. Incoming sounds are
processed and evaluated and although physiological changes continue to take place,
sleep itself is protected because awakening is a relatively rare occurrence. Adaptation
to a new noise or to a new sleeping environment (for instance in a sleep laboratory)
is rapid, demonstrating this active protection. The physiological reactions do not
adapt, as is shown by the heart rate reaction and the increase of average motility
with sound level. The autonomous physiological reactions are a normal reaction to
these stimuli, but the question is whether prolonged “abuse” of this system leads to
adverse consequences for the organism. The next chapter tries to answer that.
NIGHT NOISE GUIDELINES FOR EUROPE