AMTA  E-News

April  2010

Downside of Sitting on our Backsides
Risks of sitting too long

 Taking the stairs instead of the elevator, trips to the gym, lunch hour walks – the value of exercise is understood by both individuals and organizations. What may not be as well known are the health risks of sitting for long periods at a time – regardless of how much you exercise.

How working in a sitting position can affect your health
Those who must spend long periods in a seated position on the job such as taxi and truck drivers, call centre professionals and office workers, are at risk for injury and a variety of adverse health effects.

The most common injuries occur in the muscles, bones, tendons and ligaments, affecting the neck and lower back regions. Prolonged sitting:

• reduces body movement making muscles more likely to pull, cramp or
  strain when stretched suddenly,
• causes fatigue in the back and neck muscles by slowing the blood
  supply and puts high tension on the spine, especially in the low
  back or neck, and
• causes a steady compression on the spinal discs that hinders their
  nutrition and can contribute to their premature degeneration.

Sedentary employees may also face a gradual deterioration in health if they do not exercise or do not lead an otherwise physically active life. The most common health problems that these employees experience are disorders in blood circulation and injuries affecting their ability to move. Deep Veinous Thrombosis (DVT), where a clot forms in a large vein after prolonged sitting, sometimes called “Traveller’s Thrombosis” because it is sometimes observed after a long flight, is also a risk.

Employees, who for years spend most of their working time seated, may experience other, less specific adverse health effects. Decreased fitness, reduced heart and lung efficiency, and digestive problems are common. Recent research has identified too much sitting as an important part of the physical activity and health equation, and suggests we should focus on the harm caused by daily inactivity such as prolonged sitting.

Data collected in a 1990’s Australian study on the prevalence of diabetes and its risk factors was further analyzed by a team led by associate professor David Dunstan to determine whether people’s television viewing time was related to their metabolic health. Results showed that people who watched television for long periods of time (more than four hours a day), were at risk of:

• higher blood levels of sugar and fats,
• larger waistlines, and
• higher risk of metabolic syndrome

regardless of how much moderate to vigorous exercise they had.

In addition, people who interrupted their sitting time more often just by standing or with light activities such as housework, shopping, and moving about the office had healthier blood sugar and fat levels, and smaller waistlines than those whose sitting time was not broken up.

What does this mean for workers?
Injuries resulting from sitting for long periods are a serious occupational health and safety problem and are expected to become more common with the continuing trend toward work in a sitting position. An important step is to recognize that prolonged sitting can be a health risk, and that efforts must be made to design jobs that help people reduce and break up their sitting time.

How can you design a job that requires prolonged sitting?
The main objective of a job design for a seated employee is to reduce the amount of time the person spends “just” sitting. Frequent changes in the sitting position are not enough to protect against blood pooling in the legs or to prevent other injuries.

Five minutes of a more vigorous activity, such as walking for every 40 to 50 minutes of sitting, can provide protection. These breaks are also beneficial because they give the heart, lungs and muscles some exercise to help counterbalance the effects of sitting for prolonged periods in a relatively fixed position. Where practical, jobs should incorporate “activity breaks” such as work-related tasks away from the desk or simple exercises which employees can carry out at the workstation or worksite.

Another important aspect of job design is consulting with and getting feedback from employees. No matter how good the workplace and the job designs, there are always aspects of the job that can and must be tailored to the individual.

The bottom line: stand up, move around and get off your backside as frequently as you possibly can. But understand that physical activity is just one part of the equation for preventing the harmful effects of prolonged sitting.

More information can be found in Additional Resources below.

Additional Resources
Advice on working in a sitting position http://www.ccohs.ca/oshanswers/ergonomics/sitting/sitting_overview.html

Sitting Less: An Important Ingredient in our Recipe for Health http://www.centre4activeliving.ca/publications/research-update/2009/apr-sit-less.pdf
Alberta Centre for Active Living

Too much sitting: A novel and important predictor of chronic disease risk? http://bjsm.bmj.com/content/43/2/81.full
British Journal of Sports Medicine