Manual work can raise heart disease risk by 20 per cent, especially if it is combined with gym work outs People in physically demanding jobs more at risk than office workers And exercise in the gym can make situation even worse Greek research suggests more activity has 'overloading' effect on body Work that is physically demanding may boost your chances of suffering heart disease compared with desk jobs, claim researchers. Doing a hard day's work increases the risk of cardiovascular disease by 20 per cent more than office workers, with the risk increasing with the amount of exertion involved. The surprising find by Greek researchers runs contrary to official guidelines in most western countries which recommend physical activity to stave off heart attacks. At risk: People who do physically demanding jobs such as bricklaying are more likely to have heart problems A second study from Belgium and Denmark showed that exercise in a gym improved the coronary health of office workers but had a detrimental effect on those who already carried out manual labour as part of their job. Dr Demosthenes Panagiotakos, who led the Greek study, said people in physically demanding jobs could be under extra stress, were lower paid and might have less access to healthcare. He said it was unclear why hard work increased heart disease risk, when greater physical activity was normally linked to a lower risk. But the higher risk experienced by manual workers should make them targets for prevention by healthcare staff, he added. Making things worse: People who have physically demanding jobs increase their chance of heart disease if they work out at the gym as well Dr Els Clays, who led the Belgian and Danish study, said 'The results of this study suggest that additional physical activity during leisure time in those who are already physically exhausted from their daily occupation does not induce a 'training' effect but rather an overloading effect on the cardiovascular system.' The studies were presented yesterday at a meeting of the European Society of Cardiology in Rome. In the UK people are advised to do 150 minutes of moderate activity such as gardening, dancing or brisk walking, or 75 minutes of vigorous exercise including playing sport, running or aerobics every week. Three out of four Britons fail to achieve this. The study by Dr Panagiotakos, Associate Professor of Biostatistics-Epidemiology at Harokopio University, Athens, looked at 250 patients who suffered a first stroke and 250 who had a first heart attack, and they were compared with a control group of 500 healthy people. Stroke and heart patients were more likely to have a physically demanding jobs than those in the control group - with the more demanding jobs carrying the greatest risk, said the researchers. Having a sedentary job led to a 20 per cent lower risk of a heart attack or stroke. In a second study investigators in Belgium and Denmark looked at more than 14,000 middle-aged men who did not have heart disease and followed them for three years on average. They found physically demanding work was a risk factor for developing coronary heart disease. They also found that men in physical jobs who also did moderate to high levels of exercise in their spare time had a fourfold higher risk of heart disease. Dr Clays said 'From a public health perspective it is very important to know whether people with physically demanding jobs should be advised to engage in leisure time activity.'