Studies show that resistance training may reduce fat levels around the heart, but not all strength-based activities are beneficial for cardiovascular health. New research shows that occupational activities like routinely carrying heavy loads at work may have a negative impact on the heart.

To reach this conclusion, French and Australian researchers analyzed data collected over a 10-year period from more than 10,000 French volunteers ages 50–75. The data, gathered during regular checkups at the Paris Health Clinic, included detailed reports of frequency, intensity and duration of leisure-time, sport or work-related physical activity, along with cardiovascular health assessments based on ultrasound imaging of the carotid artery.

“[Our findings] do not suggest that movement at work is harmful for health; instead they suggest that chronic, strenuous activity (such as lifting heavy loads) at work may be,” said study author Jean-Philippe Empana, MD, PhD, of Inserm, a public research organization in France dedicated to human health.

The study is available in the American Heart Association journal Hypertension (2019; 74 [6]).