Sitting too long linked to chronic diseases


A large study led in part by K-State researcher Rick Rosenkranz, assistant professor in human nutrition, has added to the growing evidence supporting the theory that inactivity leads to chronic diseases like diabetes, heart disease and high blood pressure.

Rosenkranz’s research is relevant to college students across the country who spend hours daily sitting at desks and working on computers. Nichole Finke, senior in the interior architecture and product design, said it is normal for most of the students in the college of architecture to spend long hours sitting at their desks.

“There have been many times that I have worked either all afternoon or all evening from 7 o ‘clock to 1 in the morning,” Finke said. “It is also not uncommon for students working in the studio to suffer from back and shoulder problems.”

Research conducted by Rosenkranz, in collaboration with researchers Emma George and Gregory Kolt of the University of Western Sydney in Australia, correlated a variety of chronic diseases with the daily sitting times of over 63,000 male test subjects between the ages of 45 and 65 in the Australian state of New South Wales.

“We looked at the relationship between sitting time and chronic disease,” Rosenkranz said about the findings of the research he and his colleagues conducted. “We concluded that more physical activity and less sitting time was protective against these diseases.”

The team members conducted cross-sectional research in which they asked the candidates, who were all male because men are at greater risk than women are of contracting such diseases, to fill out a questionnaire.

The questionnaire asked them to report whether they had recently been informed of having a chronic disease by the doctor, the amount of time they spent sitting each day, educational qualifications, household income, smoking status, body-mass indices and, most important, the amount of physical activity they performed each day.

The researchers then examined the odds of chronic diseases such as heart disease, high blood pressure and diabetes. The results of the study revealed that an increase in sitting time was associated with greater odds of being affected by chronic diseases.

The odds of being affected by chronic disease were higher in men who reported sitting for between four and six hours a day. The odds increased further for men sitting between six and eight hours a day. In cases where chronic diseases were analyzed individually, men who reportedly sat between six and eight hours a day were at approximately 15 to 25 percent greater risk of contracting diabetes than men who reportedly sat for less than four hours a day.

While it might seem that college students spend a large amount of the day sitting, they do spend a considerable amount of time doing moderate physical activity. This puts them at a lower risk for chronic illnesses.

“I do spend quite a bit of time at my desk every day, but I try and make up for it by working out, going rock-climbing at the gym and doing gymnastics,” said Jacklyn Long, freshman in advertising.

While Rosenkranz’s research certainly shows a correlation between long periods of inactivity and an increased risk of chronic diseases, it is difficult to say whether the relationship between the two is causal. In a review of the research published by Bazian, an economic intelligence unit edited by the National Health association of the United Kingdom, the institution stated that the cross-sectional design used by Rosenkranz and his colleagues “cannot prove a cause and effect relationship.”

Bazian did, however, credit Rosenkranz and his collegues with validating the evidence that a sedentary lifestyle is a risk factor for health. Rosenkranz agrees with the point made by the Bazian.

“It is definitely one of the limitations of that kind of research. Our objective was to add to the general body of evidence so I believe we were successful in doing so,” Rosenkranz said. “The scientist in me tells me to suspect a causal relationship between the two and work towards definitive answers. We spend a lot time sitting at home, in class or even when at our jobs, where most of the day is spent sitting at our desk, so if there is a definite risk to our health in doing so, it is important that we make people aware.”

Rosenkranz is currently working on research to explore the causal aspect of the relationship further along with his wife, a nutritionist at K-State, to validate the findings of his previous research with college students here at K-State.

“This research will actually be in the experimental realm unlike the previous research, and we will be manipulating sitting time to test for a causal argument when it comes to sitting time and chronic illness,” Rosenkranz said.