For a man who is unfit, high physical demands at work are linked to an increased risk of death from heart disease, researchers in Denmark say. Study leader Andreas Holtermann of Bispebjerg University Hospital in Copenhagen and colleagues analyzed 2,707 men. Thirty percent of men in this group had high physical work demands, compared to 3.5 percent for those at higher socioeconomic levels, Holtermann said. The study, published in the Journal of Occupational and Environmental Medicine, found long-term risk of death from heart attack was 14 percent for men in lower social classes, compared to about 9 percent in higher social classes. However, the main risk factor was not low socioeconomic status, but rather low physical fitness -- men with low fitness and high physical work demands were nearly three times more likely to die from heart disease, compared to those with low work demands, Holtermann said. Among men who did heavy work, the heart risk was about 40 percent lower for those with high physical fitness. \"These observations indicate that physical fitness is a protector of or a risk modifier among men exposed to high physical loads on their cardiovascular system,\" Holterman said in a statement. \"The results suggest that by maintaining good physical fitness, men who engage in heavy labor can avoid increased risk, and possibly even lower their risk of death from heart disease.