The World Health Organization (WHO) places physical inactivity as the fourth-leading risk factor for global mortality, causing an estimated 3.2 million deaths annually worldwide. It ranks behind high blood pressure, tobacco use and elevated blood glucose levels and ahead of both obesity and high cholesterol, and it could be argued that all of these risks, minus tobacco use, potentially are tied to a lack of physical activity.
It's no wonder that Dr. James Levine, an endocrinologist with the Mayo Clinic, has dubbed sitting "the new smoking."
Numerous studies and reports in recent years have documented the negative, long-term health consequences of prolonged inactivity. It's the responsibility of environment, health and safety (EHS) professionals to determine whether they have workers at risk and, if they do, develop a strategy to protect the long-term health of those employees.
A 2013 independent survey commissioned by Ergotron, which manufacturers products including sit-stand desks, found that 86 percent of U.S. workers spend their work days seated. This number isn't so surprising when we think about how our economy and jobs have evolved during the past half century. Manufacturing and other manual forms of labor have been replaced with service-based occupations that often occur behind a desk in an office environment.
What is surprising is how even office jobs have changed over the years to become more sedentary. Gone, for the most part, are the days of needing to regularly get up from a desk to grab a folder from the centralized filing cabinets, documents from the fax machine or paper for the typewriter. The advent of the personal computer and the growth of modern cubicle farms have enabled employers to maximize productivity by virtually eliminating the need for workers to leave their desks. While it is a productivity gain, this technology-driven inactivity does have physical health consequences.
Health Impact of Physical Inactivity
In his research, Levine found a correlation between physical inactivity and a host of negative health consequences. There are links to the obvious – such as obesity, diabetes and high blood pressure – as well as other maladies such as cancers and mental illnesses that are not quite so obvious.
Tom Rath, another authority on the subject and the author of Eat Move Sleep bluntly states, "Sitting is the most underrated health-threat of modern time. Researchers found that sitting more than six hours in a day will greatly increase your risk of an early death."
The nature of the human body is to be active and moving during the vast majority of the day, according to Levine. And while periodic rest breaks are needed to break up the demands of physical activity, when the balance of the day tilts toward inactivity, the body begins to work against its molecular nature. To illustrate the difference in activity levels between where we're at and where we've come from, Levine cites Australian studies that showed workers in agricultural communities spend an average of three hours sitting each day while modern office workers spend between 13-15 hours each day seated.
When the human body is up and moving, the metabolism is optimized. The activity keeps muscular and cellular systems operating at peak efficiency. As Levine puts it, remaining seated for too long can trigger a cascade of adverse health consequences. In a September 2014 webcast interview with Dr. Joseph Mercola, D.O., Levine describes the impacts of extended sitting this way:
"Crunching the body into this very unnatural posture not only is sort of bad for your back, your wrists, your arms and your metabolism, but it actually switches off the fundamental fueling systems that integrate what's going on in the bloodstream with what goes on in the muscles and in the tissues. As a consequence … the blood sugar levels are inappropriately high in people who sit. The blood pressure is inappropriately high, the cholesterol handling is inappropriately high and those toxins – those growth factors that will potentially lead to cancer, particularly breast cancer – are elevated in those people who sit too much."
Link to Specific Ailments
In addition to Levine's research, a study presented at the American College of Cardiology's 64th Annual Scientific Session in March 2015 showed a link between time spent seated and coronary artery disease. The study also found evidence that the amount of exercising an individual does offers little, if any, benefit when it comes to preventing or counteracting the cardiovascular damage caused by sitting.
The study, "Sedentary Behavior is Associated with Coronary Artery Calcification in the Dallas Heart Study," analyzed heart scans and physical activity records of more than 2,000 adults living in Dallas. The research found that each hour of sedentary time per day on average was associated with a 14 percent increase in coronary artery calcification. Coronary artery calcification is a marker of subclinical heart disease that can increase the risk of a heart attack.
The data found no association between coronary artery calcification and the amount of exercise a person gets. Regular exercisers who sat for extended periods exhibited just as much calcification as non-exercisers. The study's lead author, Dr. Jacquelyn Kulinski, assistant professor of cardiovascular medicine at the Medical College of Wisconsin, acknowledged the value of exercise but added, "…this study suggests that reducing how much you sit every day may represent a more novel, companion strategy (in addition to exercise) to help reduce your cardiovascular risk."
Prolonged periods of sitting also can lead to back and hip issues. In July 2015, the National Institute for Occupational Safety and Health (NIOSH) sponsored a webinar on the implications of sedentary work, Dr. Jennifer Hess discussed how extended sitting negatively can impact functional fitness. Functional fitness basically is the body's ability to efficiently perform real world activities.
According to Hess, an associate research professor in occupational injury prevention and outreach at the University of Oregon, prolonged sitting can lead to muscle asymmetries. She said that in those individuals who are sitting for 40 hours a week, their buttock muscles become weakened which in turn forces other muscles to overcompensate. The muscles of the back often are forced to work overtime to make up for the weak buttock muscles, resulting in back injuries that manifest themselves while doing normal, everyday tasks.
Hess also noted that weakened buttock muscles can create inefficient muscle control at the top of the front of the leg leading to an increased likelihood for hip injuries. To this end, she shared a startling statistic from the American Association of Orthopedic Surgeons (AAOS). She noted that between 2000 and 2009, the AAOS reported a 123 percent increase in hip replacements in individuals between 45-64 years old. Hess said that sedentary work is a factor in this dramatic increase.
How Much Sitting is Too Much?
While there's still research needed to determine the optimal ratio between sitting and standing, at this point Levine believes that if you've been sitting for an hour straight, you've been sitting too long. He feels that you need to be up and on your feet for at least 10 minutes every hour.
Dr. Joan Vernikos, the former director of the National Aeronautics and Space Administration's (NASA's) Life Sciences Division and author of Sitting Kills, Moving Heals offers a slightly different take on what's needed to help counteract the health hazards of sitting. She believes that frequently interrupting sitting throughout the day is the key to avoiding all the negative health consequences of long hours seated.
According to her research, sedentary individuals need to stand up around 35 times per day to counteract the toll sitting takes. And these standing actions need to be spread out as equally as possible throughout the day to maximize the benefit. Going from sitting to standing 35 times all at once offers a small percent of the upside that standing once every 20 minutes provides.
And standing all day long isn't the answer either, because there are health problems associated with spending too much time on your feet. Maintaining a good balance between sitting and standing is best.
What to Do?
There are, of course, standing workstations and work desks that incorporate treadmills to allow individuals to walk while they work. There even are cycling workstations where employees can peddle throughout their work day. But with each of these options there's a financial investment and the jury's still out regarding the long-range value of these options. They all carry potential negative impacts in addition to the capital outlay.
Standing workstations are the most economical option of those described above and often can be configured with very little expense if you have a bit of creativity and ingenuity. The drawback to standing workstations is the fact that standing for prolonged periods has negative health consequences too, so some form of a sit/stand configuration is needed. This adds to the complexity of the configuration and generally adds cost.
Also, some studies have shown that certain types of work are performed better seated. There's also research that shows there's a bit of a novelty factor associated with sit/stand stations. The longer employees have them, the more inclined they are to revert to sitting verses standing throughout their workdays.
Treadmills and cycling workstations have price tags that begin in the low thousands per station and go up from there. So obviously, cost is a huge drawback. Employee safety also is a legitimate concern when it comes to working on a treadmill. There are certain activities that just cannot be performed effectively on these devices due to the movement of the arms and upper torso while walking and peddling.
With questions and concerns related to the value of an extensive workstation reconfiguration, a more basic approach may be the most logical starting point for EHS professionals looking to address sedentary jobs within their workplace. As both Levine and Vernikos point out above, it's crucial to get sedentary workers off of their bottoms on a regular basis.
Cornell University has a very comprehensive ergonomics resource center, CUErgo, and within this center experts offer some "bottom-line" advice for employers wondering where to begin. Their suggestions include:
- Sit to do computer work. Sit using a height-adjustable, downward titling keyboard tray for the best work posture, then every 20 minutes stand for eight minutes and move for two minutes. The exact time spent isn't critical but about every 20-30 minutes, take a posture break and stand and move for a couple of minutes. Simply standing is insufficient.
- Movement is important to get blood circulation through the muscles. And movement is free! Research shows that you don't need to do vigorous exercise (e.g. jumping jacks) to get the benefits, just walking around is sufficient. So build in a pattern of creating greater movement variety in the workplace (e.g. walk to a printer, water fountain, stand for a meeting, take the stairs, walk around the floor, park a bit further away from the building each day).
As with any health issue, having an awareness and appreciation of the cause and effect relationship between an action and a consequence is the first step toward fixing the problem. Some might think it hyperbole to draw a comparison between our sedentary workforce and the coal miners of the early 20th century in terms of hazardous working conditions, but research is beginning to show cause for concern.
Just how deep does the iceberg go? At this point we don't have the answer to that question but we have enough evidence that EHS professionals should begin developing strategies and implementing tactics to protect their sedentary workers.
Mike Stearns is a technical safety specialist with Grainger. He's worked for Grainger for over 29 years in various roles related to safety. In addition having a BA from the University of Wisconsin-Whitewater, Stearns also has completed the OSHA 30-hour course.