Those working in physically demanding jobs are more susceptible to heart disease than their desk-bound counterparts, new research shows Friday. Those undertaking a hard day\'s physical craft were at least 20 percent more likely to suffer from cardiovascular disease than those in an office, with the risk increasing with the amount of exertion involved, Greek researchers found in the research highlighted here by the media. A second study from Belgium and Denmark suggested that out-of-work exercise, such as 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. Men whose jobs involved strenuous physical work were four times more likely to have coronary heart disease when they also exercised in their leisure time, researchers reported. Dr. Demosthenes Panagiotakos, who led the Greek study, said the surprising results might be attributed to the extra stress experienced by people in physically demanding jobs. He also said people in manual roles were more likely to be lower paid, and therefore have less access to healthcare. Dr. Els Clays, who led the Belgian and Danish study, added: \"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. \"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 today at the EuroPRevent 2013 in Rome and published by the press here.