Uninterrupted sleep is a prerequisite for normal physiological and mental functioning. Noise can cause difficulties in falling asleep, awakenings, changes in sleep architecture (sleep structure, reduction in the proportion of sleep with rapid eye movements – REM). The main physiological effects caused by noise during sleep can cause an increase in blood pressure, acceleration of heart rate, constriction of blood vessels, changes in breathing, increased body movements. Exposure to nocturnal noise also affects the sequelae that become apparent the next day after waking such as fatigue, bad mood, reduced productivity.
The quietness of the environment makes us sleep deeper and more rested when we wake up in the morning.
According to the principles of sleep hygiene, a kind of decalogue of healthy sleep, the bedroom should be a place, darkened, with a reduced temperature (16-19 degrees Celsius, the exception is the elderly, whose bodies and requirements change with age, so for seniors it is recommended to sleep at 20 degrees) and, very importantly, soundproofed. Each of the elements enhances the processes that occur during natural sleep:
- Humans sleep best when it’s dark, because that’s when they have optimal melatonin levels,
- Falling asleep is associated with a drop in body temperature, hence we do not want to overheat at night,
- Silence allows our brains to recuperate instead of processing more stimuli.
Ensuring perfect silence in the bedroom in the modern world is not easy. The basis and first step is to effectively identify sound events during our sleep. Both their number, time of occurrence and intensity. Occasional events – noises, of not very high intensity, that are recognized by our brain do not necessarily pose a threat to our night’s rest. A car driving down the street periodically, a refrigerator turning on from time to time, or the sound of the wind outside the window may not be registered by us at all if they are a permanent part of the environment in which we sleep. Sounds below 30 dB (roughly equivalent to the volume of a leaf rustle or a whisper) are considered safe for sleep.
In contrast, sounds above 55 dB (the volume level of a vacuum cleaner or hair dryer, for example) will have a negative impact on sleep and health. At the same time, it is worth remembering that an occasional plane passing in the surroundings, although louder, will negatively affect less sleep fragmentation, compared to the sounds of cars or trains, heard constantly by people living near a highway or train station. For this reason, appropriate regulations are being created to limit the emission of noise generated by means of transportation in situations where these sources could have a detrimental effect on the health of residents who are constantly within their range.
