Half of middle-aged men who have a heart attack have shown warning signs of it up to a MONTH before Among 567 men 56 per cent had chest pain, 13 per cent had shortness of breath and 4 per cent suffered dizziness, fainting or palpitations Less than 10 per cent of people who suffer cardiac arrest outside hospital survive, which is why catching symptoms early is so important Many sudden heart attacks aren't always so sudden, new research suggests. In a study of middle-age men, more than half had possible warning signs up to a month before their hearts stopped abruptly. Cardiac arrest occurs when the heart stops due to a failure in its electrical system. Alert: Many middle-aged men who had heart attacks had suffered possible warning signs up to a month before their hearts stopped abruptly Patients can sometimes survive if they receive CPR immediately and a defibrillator is used quickly to shock the heart into a normal rhythm. Less than 10 per cent of people who suffer a cardiac arrest outside hospital survive, according to latest figures. Symptoms of a heart attack include chest pain - usually located in the centre of the chest and can feel like a sensation of pressure, tightness or squeezing - or pain in the other parts of the body. In this case, it can feel as if the pain is travelling from the chest to the arms (usually the left arm is affected, but it can affect both arms), jaw, neck, back and abdomen Other symptoms include shortness of breath, feeling sick, being sick, an overwhelming sense of anxiety (similar to having a panic attack) and feeling light-headed. Study lead author Doctor Eloi Marijon, a visiting scientist at Cedars-Sinai Heart Institute in the U.S. said: 'By the time rescuers get there, it's much too late.' Patients can sometimes survive if they receive CPR immediately and a defibrillator is used quickly to shock the heart into a normal rhythm Researchers gathered information about the symptoms and health history of men 35 to 65-years-old who had out-of-hospital cardiac arrests in the Portland area of Oregon between 2002 and 2012. Among 567 men who had out-of-hospital cardiac arrests, 53 per cent had symptoms prior to the cardiac arrest. Of those with symptoms, 56 per cent had chest pain, 13 per cent had shortness of breath and four per cent suffered dizziness, fainting or palpitations. Dr Marijon said almost 80 per cent of the symptoms occurred between four weeks and one hour before the sudden cardiac arrest. Most men had coronary artery disease, but only about half had been tested for it before their cardiac arrest. Now the researchers are conducting similar work in women. The study's senior author Doctor Sumeet Chugh, associate director for genomic cardiology at the Cedars-Sinai Heart Institute, said: 'The lesson is, if you have these kinds of symptoms, please don't blow them off. Go and see your healthcare provider. Don't waste time.' The findings were presented at the American Heart Association's Scientific Sessions. Symptoms of a heart attack include: Chest pain: usually located in the centre of your chest and can feel like a sensation of pressure, tightness or squeezing Pain in other parts of the body: it can feel as if the pain is travelling from your chest to your arms (usually the left arm is affected, but it can affect both arms), jaw, neck, back and abdomen Shortness of breath, feeling sick, being sick An overwhelming sense of anxiety (similar to having a panic attack) Feeling light headed, coughing, wheezing