Noise has been called ‘the invisible killer’ by Professor Charlotte Clark of St George’s University, University of London. ‘It is a public health crisis because we have got huge numbers of people exposed in their everyday lives.’ Noise is causing heart attacks, stroke, diabetes and dementia, insidiously affecting people even when they sleep. While no one in government wants to talk about it, ‘there is really good evidence that traffic noise affects heart health.’ she says. Only the cheerful sounds of the playground have a good effect on the body.

We have an ’emotional response to sound,’ says Professor Clark. Noise, detected by the ear, is passed onto the brain. One part of the brain, the amygdala, makes an immediate emotional assessment. If the noise seems threatening, the heart rate goes up and the nervous system is activated to release stress hormones like cortisol and adrenaline. This increases heart rate, blood pressure and general inflammation in the body. ‘If you’re exposed like this over several years, your body is reacting all the time. This increases your risk of developing things like heart attacks, high blood pressure, strokes and Type 2 diabetes. You never turn off your ears. When you are asleep, you are still listening. ‘