Men who are physically unfit and indulge in high physical work are at an increased risk of death ischemic heart disease (IHD), a new study has revealed.
Andreas Holtermann and his team from the Bispebjerg University Hospital, Copenhagen conclude that the increase in risk is not explained by the higher rates of heavy work and health risk factors among men at lower socioeconomic levels.
A previous study of 5,250 Danish men found an increased risk of death from IHD like heart attack in men with high physical work demands and low physical fitness.
However, social class was a potential confounding factor, as, men at lower socioeconomic levels are more likely to have jobs involving heavy work, and that also have higher rates of lifestyle risk factors like smoking and obesity.
To address this question, the researchers analyzed 2,707 men in the lower socioeconomic levels, with thirty percent of them having high physical work demands, compared to 3.5 percent with higher socioeconomic levels.
The long-term risk of death from IHD was 14 percent for men in the lower social classes, compared to about nine percent in the higher social classes.
However, the main risk factor was not low socioeconomic status, but rather low physical fitness, and men with low fitness and high physical work demands were nearly three times more likely to die from IHD, compared to those with low work demands.
Among men who did heavy work, the 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," the researchers said.
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.
The study has been recently published in the Journal of Occupational and Environmental Medicine.