The cacophony of noise town centres could trigger heart problems, a new study suggests, after scientists found that fluctuating sounds on busy high streets disturb normal cardiac rhythms.
Researchers from Nottingham Trent University found that constant changes in noise - even at low levels - had an immediate and disruptive effect on the patterns of participants' normal heart rates.
The team says their findings add to a growing body of research which shows how our everyday surroundings could have wider implications for long-term health.
For the study, shoppers were asked to wear mobile body sensors to monitor their heart rates as they moved about Nottingham city centre for 45 minutes.
"We found that rapid changes in noise resulted in rapid disturbance to the normal rhythm of participants' hearts," said researcher Dr Eiman Kanjo of Nottingham Trent's School of Science and Technology.
"If this pattern is repeated regularly then there is a danger it might lead to cardiovascular problems."
It is known that repeated exposure to external stresses such as noise, pollution and crowded areas can lead to a range of long term physical illnesses and behavioural issues. Recent studies have found links between noise and heart related diseases.
But the study is the first to use sensors to attempt to model the short-term impact that city environments can have upon the human body.
The researchers, from the university's School of Science and Technology, also found that air pressure had an effect on heart rate as well as an impact upon body temperature.
Environmental data including noise, air pressure and light levels were compared to data from participants relating to heart rate, body temperature and movement and changes in the electrodermal activities of the skin.
None of the participants had heart problems, but the researchers say it would be useful to study whether people with heart conditions suffered a greater impact.
The team are also calling for decision-makers to develop, implement and improve guidelines and standards to protect public health around urban spaces.
"Repeated human exposure to environmental pollutants such as noise, air pollution, traffic or even crowded areas can cause severe health problems ranging from headaches and sleep disturbance to heart disease," added Dr Kanjo.
"Many people live in and around urban areas and every day will walk along city streets and get around by cars, trains or buses.
"It's important that the issue of noise is considered when designing city landscapes. Most importantly, local authorities should look at the multiple environmental factors that might affect our health at street level."
The research was published in the journal Information Fusion.
Heart attack - Symptoms and treatment
A heart attack is a serious medical emergency in which the supply of blood to the heart is suddenly blocked, usually by a blood clot.
Symptoms can include:
• chest pain - the chest can feel like it is being pressed or squeezed and pain can • radiate from the chest to the jaw, neck, arms and back
• shortness of breath
• feeling weak and/or light-headed
• overwhelming feeling of anxiety
Not everyone experiences severe chest pain; the pain can often be mild and mistaken for indigestion. It is the combination of symptoms that is important in determining if a person is having a heart attack, not the severity of chest pain.
Treating heart attack:
• Dial 999 and ask for an ambulance, if you think you or someone you know is having a heart attack.
• If the casualty is not allergic to aspirin and it's easily available, give them a tablet (ideally 300mg) to slowly chew and then swallow while waiting for the ambulance. The aspirin will help to thin the blood and reduce the risk of a heart attack.
Further treatment for a heart attack will depend on how serious it is. Two main treatments are:
• using medication to dissolve blood clots
• surgery to help restore blood to the heart