Science · Core 7
Acoustics
Hearing never switches off.
We keep responding to sound while we sleep. Noise affects rest, concentration and, over the long term, the heart.
Why it matters
Unwanted sound triggers the body's stress response even when we are not consciously aware of it, and it can fragment sleep without fully waking us. Inside buildings, acoustics also affect how tiring a space is to be in: echo, background noise from equipment, and sound travelling between rooms.
What the research shows
Noise has effects beyond hearing. Environmental noise causes annoyance, disturbs sleep and causes daytime sleepiness, increases the occurrence of high blood pressure and cardiovascular disease, and impairs cognitive performance in schoolchildren 1.
Night-time noise is the most concerning. Noise at night disrupts sleep structure and produces arousals, rises in blood pressure and heart rate, stress hormones and oxidative stress, which may contribute to longer-term cardiovascular harm 2,3.
Guideline levels. The World Health Organization recommends keeping night-time road traffic noise below 45 dB Lnight outside the home, with lower recommended levels for rail and aircraft noise 4.
What can be done
Identify the main sources first: traffic, neighbours, plant equipment, or sound travelling within the building. Then address the weakest points: window glazing and seals, door seals, wall and floor insulation, and the location of bedrooms and study spaces. Soft furnishings and acoustic panels reduce echo in hard-surfaced rooms. Quiet, well-located heat pumps and air conditioners make a real difference at night.
How we assess it
We measure background and peak sound levels, log bedrooms overnight, assess echo in living and work spaces, and trace how sound travels between rooms and from outside.
Evidence at a glance
- Well supported
Night-time noise disturbs sleep, and long-term transport noise is linked with cardiovascular disease. 1,2
- Reasonable
Improving glazing, seals and room layout to reduce bedroom noise. Well-established acoustically; health benefits in homes are inferred from exposure studies.
General information only, not medical advice. How we grade evidence.
References
- Basner M, Babisch W, Davis A, et al. Auditory and non-auditory effects of noise on health. Lancet. 2014;383(9925):1325-1332. doi.org/10.1016/S0140-6736(13)61613-X · PubMed 24183105
- Münzel T, Gori T, Babisch W, Basner M. Cardiovascular effects of environmental noise exposure. Eur Heart J. 2014;35(13):829-36. doi.org/10.1093/eurheartj/ehu030 · PubMed 24616334
- Halperin D. Environmental noise and sleep disturbances: a threat to health? Sleep Sci. 2014;7(4):209-12. doi.org/10.1016/j.slsci.2014.11.003 · PubMed 26483931
- World Health Organization Regional Office for Europe. Environmental noise guidelines for the European Region. Copenhagen: WHO Europe; 2018. www.who.int/europe/publications/i/item/9789289053563