Physical Workload Tied to Heart Disease Risk in Swedish Men

TOPLINE:

Swedish men with physically demanding jobs in mid-life faced a higher risk of developing ischaemic heart disease (IHD) and experiencing IHD-related mortality. The risk was particularly pronounced in those who had low levels of cardiorespiratory fitness during youth.

METHODOLOGY:

• Researchers analysed data of 284,436 Swedish men born between 1951 and 1961 to examine whether high occupational physical workload in mid‐life increases the risk for subsequent IHD.
• The occupational physical workload was assessed in 2005 (age, 44-54 years); participants were followed up regarding IHD incidence and mortality during 2006-2020 (age, 45-69 years).
• Workload assessment included five different physical exposures: heavy lifting (≥ 15 kg), physically strenuous work, working in a forward bent position, working in a twisted posture, and working with hands above shoulders.
• Cardiorespiratory fitness was evaluated during mandatory military conscription using a maximal ergometer cycle test when participants were aged 18-20 years.

TAKEAWAY:

• People who had high physically demanding jobs in mid-life had a higher risk for IHD (hazard ratio [HR], 1.06; 95% CI, 1.02-1.11) and IHD mortality (HR, 1.38; 95% CI, 1.23-1.55) than those who had less physically demanding jobs, even after accounting for potential confounders.
• Those with lower levels of cardiorespiratory fitness at youth had a higher risk for both incident IHD (HR, 1.18; 95% CI, 1.14-1.23) and IHD mortality (HR, 1.30; 95% CI, 1.18-1.44).
• The risk of developing IHD was highest among individuals with low levels of cardiorespiratory fitness and medium physical workload (HR, 1.24), and the risk for IHD mortality was highest among those with low levels of cardiorespiratory fitness and the highest level of physical workload (HR, 1.60).

IN PRACTICE:

“The study results encourage both workplace and public health interventions to consider variation in occupational physical workload and to improve cardiorespiratory fitness, for a lower risk of IHD, especially in youths entering physically demanding jobs,” the authors wrote.

SOURCE:

This study was led by Karin Berglund, PhD student, Karolinska Institutet, Stockholm, Sweden. It was published online on June 12, 2025, in the European Journal of Preventive Cardiology.

LIMITATIONS:

The study population was limited to men due to military conscription, potentially limiting generalisability to women. The sample represented a somewhat healthier subset of the male population as it included only those able to participate in military conscription and complete a cycle test. Additionally, the exposure assessment was conducted at only one timepoint, not accounting for potential changes in exposures over time.

DISCLOSURES:

This study was funded by the Swedish Research Council for Health, Working Life and Welfare. The authors reported having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.