Looking for a nice, safe career that won't endanger your health? Choosing a white-collar desk job certainly beats other higher-risk occupations -- from chasing criminals and fighting fires to building bridges.
But there is a hidden danger if you're sitting down at a desk all day. In recent years, research has revealed that too much sitting can be hazardous to your health.
One study by the American Cancer Society found that people who spent six or more hours a day sitting had higher mortality rates -- 34 percent higher for women and 17 percent higher for men -- than people who spend three or fewer hours sitting.
Too much of a sedentary lifestyle has been linked to health conditions such as:
- Heart disease
It's no wonder that some have dubbed excessive sitting to be "the new smoking."
As news of the danger of sitting has spread, a trendy solution to the problem has emerged: The standing desk. But last month, researchers made an announcement that caused many standing-desk proponents to go wobbly in the knees.
A review of nearly two dozen studies concluded that there is little evidence standing desks help prevent or reverse the negative effects of sitting.
The analysis -- published in the Cochrane Database of Systematic Reviews -- found that even when computer software prompted workers to get off their duffs, the reduction in sitting time was negligible.
"We conclude that at present there is very low quality evidence that sit-stand desks can reduce sitting at work at the short term," the authors wrote.
The health risks of too much sitting or standing
However, that finding does not mean workers should simply slump back into their bad sitting habits.
Dr. Alan Hedge is a professor in the department of design and environmental analysis at Cornell University in Ithaca, New York. He specializes in research that focuses on how design and workplace ergonomics affect workers' health, comfort and productivity.
Hedge notes that sitting for more than an hour triggers biochemical changes. Although the evidence is not conclusive, it appears these changes may contribute to health conditions such as heart disease and kidney disease.
To make matters worse, the biochemical changes occur even if you are aerobically fit -- regular exercise does not appear to mitigate the dangerous effects of sitting.
Hedge says it is important to avoid sitting for prolonged periods: "Ideally, less than four hours a day," he says.
But he also cautions against excessive standing. Too much standing is tiring, as it requires about 20 percent more energy than sitting. Long periods of standing also have been shown to increase the risk of varicose veins, according to Hedge.
In addition, standing places an additional load on the circulatory system, and on the legs and feet. It also may hamper your ability to use fine motor skills.
Cornell University field studies also have found little evidence that sit-stand workstations offer dramatic health benefits. Those studies revealed that the majority of workers who try such workstations typically go back to sitting exclusively after about a month.
Standing workstations also raise health risks of their own -- including those of carpal tunnel syndrome and neck issues -- if not properly designed, Hedge says.
The right mix?
So, what is the right formula for standing vs. sitting? Hedge suggests sitting when doing computer work. Make sure you use a height-adjustable, downward titling keyboard tray.
Ideally, you should sit and work for 20 to 30 minutes before standing for eight minutes, and moving for another two minutes. Repeat that pattern throughout the day.
Hedge notes that it is crucial to go beyond simply standing to actually get moving. Movement gets blood circulating through the muscles. Even something as simple as walking over to the printer will suffice.
"Move more -- be less sedentary and more active in whichever ways," he says.
Other ways Hedge suggests for increasing movement include:
- Take the stairs instead of the elevator whenever possible
- Park further away and walk when going to stores, restaurants and other public places
- Take walks during your lunch break
- When possible, host meetings where people stand, at least part of the time.