New research suggests that high intensity, sports based exercise has benefits for cardiovascular health, but continual heavy lifting at work may have a negative impact.
Health experts have consistently promoted the benefits of physical activity, particularly for preventing cardiovascular disease, the leading cause of premature fatalities worldwide.
A study in Hypertension has now begun to look at the effect of different types of exercise on a person's cardiovascular health.
The research finds that some physical activity might actually be detrimental to a person's health.
4 different types of physical activity
Jean-Philippe Empana of Inserm/Université de Paris, in France, working with colleagues from Australia, led the research.
The authors analyzed data from the 10-year Paris Prospective Study III, which is tracking the health of 10,000 people from 50 to 75 years of age.
As part of that study, participants filled out questionnaires in which physical activity was in four different categories:
- high intensity sports activities
- exertion from job-related tasks, such as lifting and moving heavy objects
- low impact exercise from leisure activities, such as walking with friends, gardening, etc
- total physical activity
"Our idea was to look at whether all types of physical activity are beneficial, or whether, under some circumstances, physical activity can be harmful," says Empana.
"We wanted, in particular, to explore the consequences of physical activity at work, especially strenuous physical activity, such as routinely carrying heavy loads, which could have a negative impact."
To track the cardiovascular health of the participants, the researchers examined their arteries, using ultrasound imaging of the carotid arteries in their necks.
Specifically, they measured the sensitivity of the baroreflex mechanism; the baroreflex mechanoreceptors in the carotid and aorta blood vessels control the body's rapid response to — and accommodation of — changes in blood pressure.
A compromised baroreflex system increases the likelihood of serious outcomes, including cardiac arrest.
Two aspects of the baroreflex system were measured:
- Mechanical baroreflex, as reflected by arterial stiffness. Problems with this aspect of the system are often part of age-related cardiovascular problems.
- Neural baroreflex, or the neural impulses that the mechanoreceptors transmit on the artery wall." Neural baroreflex insufficiencies often lead to heart rhythm problems and cardiac arrest.
The major takeaways
Empana and his colleagues saw two significant trends from their results.
First, sports based physical activity strengthens the neural baroreflex, thus reducing the chances of cardiac issues — as health experts have long been suggesting.
On the other hand, they found that strenuous exertion at work has a negative effect on both arterial stiffness — the mechanical baroreflex — and the neural baroreflex, producing a higher risk for heart rhythm problems.
The authors found no particular connection between leisure activity or total activity and either mechanical or neural baroreflex.
"Our findings," says Empana, "represent a valuable avenue of research for improving our understanding of the associations between physical activity and cardiovascular disease. They 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."
Next up for the researchers are attempts to see if these results are consistent across other groups of people.
"This study has major public health implications for physical activity at work," Empana concludes. "We now want to expand our analysis to further explore the interactions between physical activity and the health status of people in the workplace."