Sitting at work bad for health - study

Office workers who spend most of the day seated are more likely to suffer from chronic diseases like cancer, diabetes and heart disease, research suggests.

The findings of the Australian study are likely to be reflected in New Zealand, which has similar rates of chronic disease, according to a public health expert here.

Researchers from the University of Western Sydney's School of Science and Health surveyed more than 63,000 Australian men aged 45-64 on their daily sitting time.

They compared the rates of chronic disease among participants who sat for less than four hours, four to six hours, six to eight hours, and more than eight hours.

Researcher Emma George said people who spent more time seated were much more likely to report serious health conditions - including diabetes, cancer, heart disease and high blood pressure - compared with those who were seated for less than four hours.

"The rates of chronic diseases reported by the participants exponentially increased in proportion with the amount of time the participants spent sitting down."

The researchers said the study, which was published in the International Journal of Behavioural Nutrition and Physical Activity, was highly relevant to office workers and others whose job requires them to sit down for long periods of time, such as truck drivers.

Public health expert Professor Grant Schofield, the director of AUT's human potential centre, said he expected similar findings in New Zealand.

The centre has collected data from more than 10,000 people as part of its Wellbeing Index project - and researchers are hoping to analyse how much time New Zealanders spend seated within the next few months.

Dr Schofield said sitting had an impact on health, regardless of how much people exercised, because sitting for a long time activated an enzyme called lipoprotein lipase, which encouraged cells to store extra energy as fat.

"It's only really recently that humans have taken up marathon sitting, and marathon anything is likely to be bad for you," he said.

"Humans just weren't made to sit around through their whole day."

That was reflected in the Australian research, which found the amount of sitting time was significantly associated with chronic disease, independent of factors like physical activity, age and weight.

Dr Schofield said exercise was good for energy expenditure but it also required willpower, which could be "pretty fragile".

"Even a half-hour run, compared to the amount of energy that you'd use up over a day where you're moving around as part of your job, is incidental," he said.

"We're concentrating on exercise, which is great, but there's more to it than we thought."

Dr Schofield said standing at work had benefits, so reshaping the office environment could help tackle the problem.

"Contrary to just tiring you out, it actually energises you a bit more. You can actually buy desks which are highly adjustable - it just doesn't have to be that hard."