Which is more likely to lead to a heart attack on the job – prolonged sitting or standing?

Jobs that require workers to stand most of the time put their employees at a greater risk of heart disease than workers who mainly sit, a new Canadian study has found.

According to researchers at the Institute for Work & Health (IWH) and the Institute for Clinical Evaluative Sciences (ICES), prolonged standing was found to have increased the risk of heart disease in workers by 6.6 per cent. That chance decreased to 2.8 per cent among employees who predominantly sat.

“Workplaces have been hearing a lot lately about the health effects of prolonged sitting on the job,” senior scientists and lead researcher Dr. Peter Smith said in a statement. “Our results suggest that workplaces also need to pay attention to the health effects of prolonged standing, and target their prevention programs accordingly.”

The study followed 7,300 workers from Ontario between the ages of 35 and 74 who were initially free of heart disease for a span of 12 years, the study says.

Participants were pulled from the 2003 Canadian Community Health Survey (CCHS), which collection information on a variety personal factors like health conditions, health behaviours and work conditions. Also collected was job title information (which was used to see if a job included more sitting, standing/walking, a combination of sitting/standing/walking or other body postures like bending or kneeling).

Of those involved in the study, nine per cent were estimated to spend most of their time standing at work while 37 per cent were estimated to predominantly sit. From there, researchers linked CCHS information to administrative health records at ICES between 2003 and 2015 to identify new cases of heart disease.

Over this time period, 3.4 per cent of people developed heart disease. To break it down further, men were found to have the highest chances of developing the disease (4.6 per cent) compared to women (2.1 per cent). Without taking any other factors into account, the study found that the unadjusted risk of heart disease was higher among those who stand than workers who sit (6.6 per cent and 2.8 per cent, respectively).

But when researchers adjusted for such factors – personal (like age, gender, education, ethnicity, immigrant status and marital status), health conditions, health behaviour (like smoking, drinking, exercising and body mass index) and work (like physical demands and shift schedule) – the risk of develop heart disease was actually twice as high among standers than sitters.

In fact, the unadjusted risk of heart disease among standers (6.6 per cent as mentioned above) was even higher than among daily smokers (5.8 per cent), researchers say.

“A combination of sitting, standing and moving on the job is likely to have the greatest benefits for heart health,” Smiths says. “Workplaces need to apply this message not just to workers who predominantly sit, but also – in fact, especially – to workers who predominantly stand.”

However, researchers found that such a combination of sitting, standing and moving doesn’t work for everyone. Men, they say, are those most likely to benefit in a decreased risk of heart disease while women do not.

Smith believes it is because jobs like nursing and teaching tend to be populated more by women in the “sitting, standing and walking” category,” – jobs that are known to be stressful “in different ways.”

Other studies over the years have also looked into the link between one’s lifestyle at work and the impact it has on workers’ health.

Earlier this year, researchers at the University of Warwick concluded that desk jobs were both bad for one’s heart as well as their waistlines.

Sedentary work, researchers say, adds about two centimetres to the waistline and increases the risk of heart disease by 0.2 per cent for every additional hour of sitting on top of five hours.

“Longer time spent in sedentary posture is significantly associated with larger waist circumference, higher triglycerides (fat in the blood) and lower HDL cholesterol, all adding up to [a] worse risk of heart disease,” study author Dr. William Tigbe said in a statement.

“The levels associated with zero risk factors were walking more than 15,000 steps per day, which is equivalent to walking seven to eight miles, or spending seven hours per day upright.”