21/04/2010

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
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 analysed 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. Other
important factors include chair selection, workstation design and training.


More information:


AplusA-online.de - Source: Canadian Centre for Occupational Health and Safety