Is it sitting time that causes pain among blue collar workers?

“Many believe that those who have heavy jobs are more active than what they are in reality,” says David Hallman researcher at Gävle University.

Sitting is common even in heavy jobs
Work on an assembly line, production work, cleaning, construction work, renovation, road construction and care work; these are all occupations where one sits at work a great deal and in the spare time, that it can pose a health risk.

Researchers from Gävle University and the Danish National Research Centre for the Working

Environment, have measured exactly how much people sit in these occupations, during several working days, by letting 200 people carry accelerometers on the thigh and back.

They found that, on average, people sit approx. 8 hours a day, 3 hours at work and 5 hours in their spare time.

“It is unusual that one investigates sitting time in such a detailed manner in these types of occupations.

The health effects of lengthy sitting time have usually been studied within office jobs. And in earlier studies one has just asked people how much they sit,” says David Hallman.

Sitting time increases at home
Sitting time, both at work and in spare time, has significance. It is the amount that one sits throughout the whole day that leave repercussions.

“In this group one increases one’s sitting time when one gets home from work; one is very inactive in one’s spare time. If you combine all the sitting time during a 24-hour period then there are very many hours of sitting.

According to the recommendations one should be active 10 minutes at a time and generally have 30 such active periods during a whole day. Extremely few people reach this level during their spare time.”

Three times greater risk
We see a rather clear connection between how much people sit down at work and in their spare time, and how much pain they have in their lower back region. We even see a similar connection for pain in the neck, even if not as obvious.

“There is a three times greater risk of getting neck and lower back pain if you sit down for eight or more hours per day,” David Hallman.

Earlier, at Gävle University, we have studied people with chronic neck pain and compared them to healthy individuals, but there we did not find that sitting times made any difference. This means that one does not start sitting just because one is in pain.”

Is there something one does when one sits?
Researchers have suspected that sitting can have significance when reporting pain in the neck. But because one has not measured it using a reliable method, one has not been able to draw logical conclusions from earlier studies.

The group that one has studied recently, selected because it is a risk group, report a lot of pain and even cardio-vascular illness. It is a risk group for ill-health that also has a heavy workload in their job.

“If one sits less at work then less pain is reported. We see this connection for both neck pain and lower back pain. But we still cannot understand if sitting per se is a risk factor or if it is something one does when one sits.”

What happens over time?
The researchers have now made the same collection of data, using people in the same types of occupations, but this time using 700 people.

”We are going to look at it in more detail and see if sitting time also has a significance for what happens with pain over time. Test persons have had to answer questions via SMS about what happens regarding the pain, every month, for a whole year.”

Links to the original articles:

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0121159

http://link.springer.com/article/10.1007/s00420-015-1031-4

For more information please contact:
David Hallman, Centre for Musculoskeletal Research, Gävle University
Tel: 026-648439, 073-626 64 13
Email: david.hallman@hig.se

Text:Douglas Öhrbom