Nurses with high blood pressure and physically demanding jobs are nearly three times more likely to develop heart disease as those with normal pressure and less active roles, according to researchers.
Lead author Karen Allesøe, from the University of Southern Denmark, said: “Previous research has shown that men and women with physically demanding jobs have an increased risk of heart disease.
“Lifting and carrying cause a rise in blood pressure and may put people with hypertension at particular risk of a cardiovascular event,” she said. “We wanted to investigate whether women with hypertension and physically demanding jobs have an especially high risk of heart disease.”
The study, published in the European Journal of Preventive Cardiology, included 12,093 female nurses who had taken part in the 1993 Danish Nurse Cohort Study.
Data on hypertension and physical activity at work were collected via questionnaire. Activity was classified as “sedentary”, “moderate” – mainly standing and walking, but not physically exerting – or “high” – standing or walking with some lifting or carrying, and heavy or fast and physically exerting.
Nurses with hypertension and high physical activity were compared to nurses with normal blood pressure and moderate physical activity at work – the latter deemed the most healthy combination, as both high physical activity and long periods of sitting increase CVD risk.
During the 15-year follow up, 580 nurses developed ischaemic heart disease. Nearly 12% reported having hypertension. Physical activity at work was reported as “high” in 46.3% of the nurses, “moderate” in 34.4% and “sedentary” in 19.3%.
The researchers found hypertensive nurses with high physical activity at work had a nearly three times higher risk of heart disease than nurses with normal blood pressure and moderate activity.
Nurses with normal blood pressure and high physical activity had a small increased risk of heart disease, but it was not significant after adjusting for established CVD risk factors, such as diabetes and smoking.
“This study among nurses indicated that hypertensive women may be at particular high risk of IHD from physically demanding work”
The combination of hypertension and high physical activity at work increased the risk of ischaemic heart disease more than adding the individual risks together, said the study authors.
For example, around five additional cases of heart disease were found due to high physical activity at work and around 15 extra cases from hypertension. While 20 extra cases would be expected from the combination, the researchers found more than 60 additional cases.
Ms Allesøe said: “This implies that there is an additive interaction between hypertension and high physical activity at work.
“The two risk factors appear to work together, resulting in an even greater incidence of heart disease,” she said. “It means hypertensive women with physically demanding work may be especially at risk of heart disease. To our knowledge, this has not been shown before among women.”
The researchers noted that physically demanding work increased heart rate and blood pressure, while a higher heart rate could lead to plaques in the arteries and atherosclerosis, as could hypertension. In addition, lifting and carrying heavy loads may cause an acute rise in blood pressure that could be harmful in people with hypertension.
Ms Allesøe said: “For nurses, physically demanding jobs may involve high force demands during patient handling, or standing and walking all day with no time for breaks.”
She added: “We need more information on which aspects of physically demanding work are harmful. Until then we cannot make specific recommendations on how much lifting, and for how many hours, is safe for women with hypertension.
“If our findings are replicated in other studies there would be grounds for occupational health counselling for women with hypertension to ensure the physical aspects of their jobs do not increase their risk of heart disease,” she said.