People who stand for long periods at work may have another reason to join their seated colleagues in moving more.
When researchers followed 7,300 Ontario workers aged 35 to 74 who were free of heart disease, they found the risk of heart disease was higher among those whose job titles involve mainly standing compared with those who mainly sit.
“There’s a good body of research evidence that shows standing a lot, it’s actually bad for your health,” said Peter Smith, a senior scientist at the Institute for Work & Health and an associate professor at the Dalla Lana School of Public Health at the University of Toronto.
“There are things like blood pooling in your legs, the venous return, the pressure on your body to pump blood back up to your heart from your legs, and that can increase your oxidated stress which can increase your risk of heart disease.”
The occupations that involved prolonged standing included cashiers, chefs and machine tool operators who stand for four or five hours at a time, said Smith and his team of researchers from the Institute for Clinical Evaluative Sciences.
About nine per cent of the subjects in the 12-year study mainly stood at work when the study began compared with 37 per cent who were estimated to sit most of the time.
They responded to the 2003 Canadian Community Health Survey by answering questions about their age, education level, ethnicity, chronic health conditions, height and weight, shift schedule and smoking, drinking and amount of leisure physical activity.
Limitations of the study included the self-reported measures, one-time answers and a lack of objective checks of standing and sitting time.
“If you allow people who stand a lot the opportunity to sit and give those breaks of sitting and standing throughout the day, you would probably do a lot to decrease your risk of cardiovascular disease,” Smith suggested.
‘Solution to sitting may not be standing’
In general, being sedentary or sitting too much is bad for health, Smith said, adding the jury is out on the long-term health effects of prolonged sitting at work.
“The solution to sitting may not be standing,” said Dr. David Alter, a cardiologist and a senior scientist at the University Health Network’s Toronto Rehabilitation Institute, who was not involved in the study.
“The solution to sitting may be movement. Insofar that the study sheds light on that, I think it contributes to our knowledge.”
Alter advises people to track how long they’re seated and to try to vary their position every 30 minutes.
Since physical activity seems to counterbalance the bad effects of not moving to some degree, Alter encourages adults to get 150 to 300 minutes a week of moderate to vigorous physical activity. That’s a pace that causes you to sweat a bit and raises your heart rate.