There was a time when standing desks were a curiosity—used by eccentrics like Hemingway, Dickens and Kierkegaard, but seldom seen inside a regular office setting.

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That's changed, in large part due to research showing that the cumulative impact of sitting all day for years is associated with a range of health problems, from obesity to diabetes to cancer. Because the average office worker spends 5 hours and 41 minutes sitting each day at his or her desk, some describe the problem with a pithy new phrase that's undeniably catchy, if somewhat exaggerated: "Sitting is the new smoking."

Much of this research has been spurred by James Levine, an endocrinologist at the Mayo Clinic. "The way we live now is to sit all day, occasionally punctuated by a walk from the parking lot to the office," he recently said during a phone interview, speaking as he strolled around his living room. "The default has become to sit. We need the default to be standing."

All this might sound suspiciously like the latest health fad, and nothing more. But a growing body of research—conducted both by Levine and other scientists—confirms that a sedentary lifestyle appears to be detrimental in the long-term.

The solution, they say, isn't to sit for six hours at work and then head to the gym afterward, because evidence suggests that the negative effects of extended sitting can't be countered by brief bouts of strenous exercise. The answer is incorporating standing, pacing and other forms of activity into your normal day—and standing at your desk for part of it is the easiest way of doing so. Here's a list of some of the benefits scientists have found so far.

Reduced Risk of Obesity

Levine's research began as an investigation into an age-old health question: why some people gain weight and others don't. He and colleagues recruited a group of office workers who engaged in little routine exercise, put them all on an identical diet that contained about 1000 more calories than they'd been consuming previously and forbid them from changing their exercise habits. But despite the standardized diet and exercise regimens, some participants gained weight, while others stayed slim.

Eventually, using underwear stitched with sensors that measure every subtle movement, the researchers discovered the secret: the participants who weren't gaining weight were up and walking around, on average, 2.25 more hours per day, even though all of them worked at (sitting) desks, and no one was going to the gym. "During all of our days, there are opportunities to move around substantially more," Levine says, mentioning things as mundane as walking to a colleague's office rather than emailing them, or taking the stairs instead of the elevator.

Failing to take advantage of these constant movement opportunities, it turns out, is closely associated with obesity. And research suggests that our conventional exercise strategy—sitting all day at work, then hitting the gym or going for a run—"makes scarcely more sense than the notion that you could counter a pack-a-day smoking habit by jogging," as James Vlashos puts it in the New York Times. The key to reducing the risk of obesity is consistent, moderate levels of movement throughout the day.

Scientists are still investigating why this might be the case. The reduced amount of calories burned while sitting (a 2013 study found that standers burn, on average, 50 more calories per hour) is clearly involved, but there may also be metabolic changes at play, such as the body's cells becoming less responsive to insulin, or sedentary muscles releasing lower levels of the enzyme lipoprotein lipase.

Of course, all this specifically points to danger of sitting too much, not exactly the same as the benefit of standing. But Levine believes the two are closely intertwined.

"Step one is get up. Step two is learn to get up more often. Step three is, once you're up, move," he says. "And what we've discovered is that once you're up, you do tend to move." Steps one and two, then, are the most important parts—and a desk that encourages you to stand at least some of the time is one of the most convenient means of doing so.

Reduced Risk of Type 2 Diabetes and Other Metabolic Problems

The detrimental health impacts of sitting—and the benefits of standing—appear to go beyond simple obesity. Some of the same studies by Levine and others have found that sitting for extended periods of time is correlated with reduced effectiveness in regulating levels of glucose in the bloodstream, part of a condition known as metabolic syndrome that dramatically increases the chance of type 2 diabetes.

A 2008 study, for instance, found that people who sat for longer periods during their day had significantly higher levels of fasting blood glucose, indicating their their cells became less responsive to insulin, with the hormone failing to trigger the absorption of glucose from the blood. A 2013 study [PDF] came to similar findings, and arrived at the conclusion that for people already at risk of developing type 2 diabetes, the amount of time spent sitting could be a more important risk factor than the amount of time spent vigorously exercising.

Reduced Risk of Cardiovascular Disease

Scientific evidence that sitting is bad for the cardiovascular system goes all the way back to the 1950s, when British researchers compared rates of heart disease in London bus drivers (who sit) and bus conductors (who stand) and found that the former group experienced far more heart attacks and other problems than the latter.

Since, scientists have found that adults who spend two more hours per day sitting have a 125 percent increased risk of health problems related to cardiovascular disease, including chest pain and heart attacks. Other work has found that men who spend more than five hours per day sitting outside of work and get limited exercise were at twice the risk of heart failure as those who exercise often and sit fewer than two hours daily outside of the office. Even when the researchers controlled for the amount of exercise, excessive sitters were still 34 percent more likely to develop heart failure than those who were standing or moving.

Reduced Risk of Cancer

A handful of studies have suggested that extended periods of sitting can be linked with a higher risk of many forms of cancer. Breast and colon cancer appear to be most influenced by physical activity (or lack thereof): a 2011 study found that prolonged sitting could be responsible for as much as 49,000 cases of breast cancer and 43,000 cases of colon cancer annually in the U.S. But the same research found that significant amounts of lung cancer (37,200 cases), prostate cancer (30,600 cases), endometrial cancer (12,000 cases) and ovarian cancer (1,800 cases) could also be related to excessive sitting.

The underlying mechanism by which sitting increases cancer risk is still unclear, but scientists have found a number of biomarkers, such as C-reactive protein, that are present in higher levels in people who sit for long periods of time. These may be tied to the development of cancer.

Lower Long-Term Mortality Risk

Because of the reduced chance of obesity, diabetes, cardiovascular disease and cancer, a number of studies have found strong correlations between the amount of time a person spends sitting and his or her chance of dying within a given period of time.

A 2010 Australian study, for instance, found that for each extra hour participants spent sitting daily, their overall risk of dying during the study period (seven years) increased by 11 percent. A 2012 study found that if the average American reduced his or her sitting time to three hours per day, life expectancy would climb by two years.

These projects control for other factors such as diet and exercise—indicating that sitting, in isolation, can lead to a variety of health problems and increase the overall risk of death, even if you try to get exercise while you're not sitting and eat a healthy diet. And though there are many situations besides the office in which we sit for extended periods (driving and watching TV, for instance, are at the top of the list), spending some of your time at work at a standing desk is one of the most direct solutions.

If you're going to start doing so, most experts recommend splitting your time between standing and sitting, because standing all day can lead to back, knee or foot problems. The easiest ways of accomplishing this are either using a desk that can be raised upward or a tall chair that you can pull up to your desk when you do need to sit. It's also important to ease into it, they say, by standing for just a few hours a day at first while your body becomes used to the strain, and move around a bit, by shifting your position, pacing, or even dancing as you work.