So many jobs today are sedentary, involving primarily computer use and other office automation that we handle most tasks without leaving our desks. Between email and telephones, we seldom leave our desks to communicate with colleagues down the hall. Conference calls, webinars, and Skype allow us to meet with colleagues across the country as we sit at our desks. Perhaps due to concerns about the health effects of all that sitting, more employees, in our experience, are requesting to incorporate treadmills, stationary bicycles, exercise balls, and sit-stand desks into workstations. While the health benefits of these “active” workstations may appear obvious, occupational health and safety professionals need to consider their potential impacts on workplace safety and productivity. 
Another systematic review that appeared in the International Journal of Environmental Research and Public Health in 2018 found similar mixed results regarding workplace productivity and performance when using active workstations, with one important addition: “It appears that using a sit-stand workstation has no effect on productivity when the person is standing,” the researchers wrote, “indicating that alternating between standing and sitting may not have any detrimental effect on the amount and quality of work being produced.” ERGONOMIC AND SAFETY IMPACTS In our view, research does not suggest a strong health benefit that would justify utilizing exercise furniture as standard practice. In addition, use of such furniture can increase the risk of an MSD by permitting or even requiring non-neutral postures. With neutral posture, the body is aligned to follow natural curves and balanced to minimize stress on muscles and joints. Appropriate office furniture is designed to permit and support neutral posture for the entire body for each task. It is critical for workstations to minimize ergonomic risk factors such as awkward postures, repetitive or long-duration tasks, and the need for excessive force.  Awkward postures involve more than not standing straight. Poor posture is a risk factor that makes the body work harder when joints are misaligned. Poor posture can also increase the amount of force necessary to work if joints are not in the midrange of motion. Office work in particular has the added risk factor of static posture—that is, holding the same posture for lengthy durations. Adjustable furniture like a sit-stand workstation can adapt the monitor and keyboard height to obtain neutral computing postures and allow those postures to change over the workday.  While exercise furniture might address static postures, its use may have unintended consequences. For example, a ball chair is not height adjustable, so a position too close to the floor could mean that the user must reach up to the keyboard, creating stress on forearms and wrists, and look up at the monitor, increasing visual demands and requiring poor neck posture (especially for wearers of bifocals or trifocals). Both the ball chair and the cycle chair lack armrests and lumbar support. Unsupported arms increase the risk of wrist, elbow, and shoulder problems. Users may be tempted to use the desk as an armrest as they tire, which means they will no longer be maintaining neutral lumbar posture. Falling and tripping are major safety risks as the transition between sitting and standing is less stable than with a conventional chair. Some ball chairs use a frame with lumbar support, eliminating some of the instability of sitting on the ball alone. But the stability of the frame defeats the purpose of the ball chair. A worker might as well sit in a conventional desk chair (with conventional support and stability).  Under-desk cycles are used with regular office chairs, so adjustability and stability are not affected. However, other risk factors can result in less-than-ideal posture. When not in use, the pedals get in the way of leg room under the work surface. Seated chair height can often be compromised to accommodate knee clearance while pedaling, which results in poor working postures of elevated upper extremities and increases the reach and force necessary to perform tasks.  Similar concerns arise with treadmill desks. Walking can induce extra head and eye movements to read the screen. Walking while using voice recognition software could decrease accuracy due to increased breathing rate. Increased overall body fatigue is a concern as well. Treadmill desks pose acute risks that a stationary workstation does not: specifically, slips, trips, or falls from “distracted walking.” Treadmill desks need numerous safety features such as a safety tether, handrails, and speed limitations as well as proper clothing, particularly shoes. Whether using an exercise ball as a chair or a treadmill desk, users will eventually get tired and need to use a regular chair at some point during the workday.  At the same time, a basic risk factor for MSDs is static work posture. Thus, changing positions throughout the day is critical, more frequently than just taking a walk or hitting the gym at lunch time. Altering work postures throughout the day is key to reducing musculoskeletal discomfort. Ideally, workers will change postures as often as every thirty minutes. A 2014 study in Ergonomics in Design demonstrated that combining the sit-stand workstation with software-generated reminders to switch positions reduced discomfort without negative effects on productivity when performing tasks such as keyboarding, mousing, and making phone calls. Whether the worker is sitting or standing, proper ergonomic principles must be applied in relation to the position of the keyboard, monitor, input device, and document. 
FACILITY AND CORPORATE IMPACTS Typically, to provide good indoor air quality as well as thermal comfort, air handling systems serving office spaces are designed with the capacity to meet certain criteria for temperature, relative humidity, minimum outside air uptake, and airflow rate. If computer workstations equipped with exercise bicycles or treadmills are introduced into office environments, then the heating, ventilating, and air-conditioning (HVAC) systems serving those environments would have to be modified at increased cost to account for the additional heat load that exercising personnel produce.  The introduction of exercise furniture will also require more space per person since it will need to fit alongside conventional office furniture. Conventional furniture will still be necessary for employees to use when they get tired. Many office facilities may not have the space necessary to allow every worker to have a treadmill desk, for example, raising questions of fairness and the need for criteria to determine who can or should have such a workstation. Employers may be forced to require a “fitness for duty” medical exam or a legal waiver of liability as well as other administrative controls. Office layouts in which some workstations are exercise-capable and others are not will not be uniform, which may detract from their overall appearance, and the use of such workstations will likely add another source of distraction to open office areas. Sit-stand workstations are the exception: these are designed to take the same space as a conventional desk and utilize conventional seating when the user gets tired of standing. A HEALTHY CULTURE The bottom line is that definitive benefits from the use of exercise equipment as office furniture have yet to materialize. Research suggests that such use results in limited energy expenditure and frequently in diminished work performance. Studies rarely address the risks of slips, falls, and MSDs, much less the potential for workers’ compensation claims.  A recommended approach for defining the office furniture permitted in the workplace is to look to the standards. Industrial hygienists perform hazard assessments of procedures, tasks, and equipment including furniture. The process of controlling the hazard starts with a review of current regulations, standards, and guidelines. For respiratory protection, hygienists look to OSHA regulations, NIOSH guidelines, and non-regulatory Threshold Limit Value standards. For office furniture, hygienists have the ANSI/HFES and ANSI/BIFMA standards. When enough research is available on how to build a safe treadmill desk or bicycle chair, BIFMA will likely add a standard for them. Until then, we recommend developing a workplace culture that invites employees to adopt healthy workplace practices to limit sedentary behavior at work. Such practices are simple and easily incorporated into the workday:
  • Stand during meetings, while on the phone, or reading.
  • Take frequent micro-breaks at the desk to stand and stretch.
  • Take a brief walking break, perhaps a lap around the building or the floor.
  • Walk down to a colleague’s desk rather than call or email.
  • Use the stairs rather than the elevator.
  • Participate in lunchtime exercise classes, if offered.
These behaviors accomplish the same purpose as exercise equipment—a change in posture and movement—and minimize the risk of MSDs. None of them need an “exercise device” to be effective. An important part of this culture is reminding employees, coworkers, and managers that taking a break is not wasted time, but rather a healthy and productive practice.    PENNEY M. STANCH, PT, CPEE, CIE, is a senior consultant with Baer Engineering and Environmental Consulting, Inc., in Austin, Texas. MARJORIE WERRELL, PT, CPEE, CIE, is president of Ergoworks Consulting in Gaithersburg, Md. ALBERT MOORE, MS, CIH, CPE, CLSO, is a PhD student with Industrial & Systems Engineering at Virginia Tech in Blacksburg, Va. STEPHEN W. HEMPERLY, MS, CIH, CSP, CLSO, FAIHA, is an advisory industrial hygienist with Western Digital in San Jose, Calif. Send feedback to The Synergist.
Clinical Biomechanics: “Sitting on a Chair or an Exercise Ball: Various Perspectives to Guide Decision Making” (May 2006). Ergonomics in Design: “Stand Up and Move; Your Musculoskeletal Health Depends on It” (July 2015).  Human Factors: “Stability Ball Versus Office Chair: Comparison of Muscle Activation and Lumbar Spine Posture During Prolonged Sitting” (2006). Human Factors: “The Effects of Walking and Cycling Computer Workstations on Keyboard and Mouse Performance” (December 2009). International Journal of Environmental Research and Public Health: “The Impact of Active Workstations on Workplace Productivity and Performance: A Systematic Review” (February 2018). Journal of Physical Activity and Health: “Cognitive Function During Low-Intensity Walking: A Test of the Treadmill Workstation” (May 2014). Journal of Physical Activity and Health: “Effect of Using a Treadmill Workstation on Performance of Simulated Office Work Tasks” (2009). Journal of Physical Activity and Health: “Metabolic Cost and Speech Quality While Using an Active Workstation” (March 2011).  Obesity: “Treadmill Desks: A 1-Year Prospective Trial” (April 2013). Occupational and Environmental Medicine: “Health and Productivity at Work: Which Active Workstation for Which Benefits: A Systematic Review” (May 2019). PLoS ONE: “Cognitive and Typing Outcomes Measured Simultaneously with Slow Treadmill Walking or Sitting: Implications for Treadmill Desks” (April 2015). Preventative Medicine: “A Systematic Review of Standing and Treadmill Desks in the Workplace” (January 2015).
In our view, research does not suggest a strong health benefit that would justify utilizing exercise furniture as standard practice.
STANDARDS When confronted with a workplace hazard, occupational health and safety professionals typically look for an applicable standard to determine the established practices and procedures for protecting the workforce. Currently, OSHA has no specific regulations regarding ergonomics. The agency does offer guidelines such as the OSHA Computer Workstations eTool. Nonregulatory standards are provided by the American National Standards Institute (ANSI), the Human Factors and Ergonomics Society (HFES), and the Business and Institutional Furniture Manufacturers Association (BIFMA). ANSI maintains several standards regarding the design and engineering of computer workstations and related office furniture. HFES compiles the latest scientific data into the volume ANSI/HFES 100-2007 Human Factors Engineering for Computer Workstations, providing requirements and guidance on the design, configuration, and installation of workstations focused on the human-machine interface. BIFMA publishes the BIFMA G1-2013 Ergonomics Guideline for Furniture Used in Office Work Spaces Designed for Computer Use with guidance on function and range of adjustments for office furniture. BIFMA also manages the ANSI/BIFMA standards for workplace furniture, with separate standards for each type of furniture (for example, ANSI/BIFMA X5.1 – 2017, Office Chairs and ANSI/BIFMA X5.5 – 2014, Desk Products). In addition to comfort, these standards include requirements for safety, sustainability, and durability. Purchasing ANSI-, HFES-, and BIFMA-compliant furniture alone does not ensure employees will be protected from work-related musculoskeletal disorders. But this furniture should increase the likelihood that the workstation can be configured and adjusted to meet the needs of the individual employee and task. The latest updates to these standards incorporate guidance for performing computer operations while standing as well as sitting; however, there are currently no standards for exercise/office furniture such as a treadmill desk or bicycle chair. EFFECTS OF EXERCISE ON PRODUCTIVITY Examples of office furniture that combine exercise equipment with typical desks and chairs include height-adjustable sit-stand workstations, treadmill desks, cycle chairs, under-desk cycles, and exercise ball chairs. These products purport to offer some of the same health benefits as exercise without requiring workers to leave their desk. Employers that offer this equipment also assume that employees can be just as productive while exercising as when working in traditional office furniture. Today’s exercise furniture attempts to integrate “modified” exercises into computer workstations. The research we reviewed suggests that treadmill and cycle desk exercises fail to mimic the same aerobic activity as running. Nor do these exercises substitute for strength training such as lifting weights. Ball chairs may provide therapeutic exercise targeting specific muscle groups in the gym, but they do not provide the stability needed for long-term seated office work. Employees are unable to maintain a strong core posture throughout the day. One study published in Applied Ergonomics in 2009 found constant lower-back muscle and trunk activation while using a ball chair, which leads to fatigue and can place the worker at risk for assuming awkward postures over time. Compression of the soft tissue of the posterior surface of the thigh may also cause discomfort over time versus a standard chair that distributes the weight safely to the ischial tuberosities (the sit bones), according to studies in Human Factors and Clinical Biomechanics.  Studies on the quality of exercise provided by treadmill desks yield varied results.  Two studies in the Journal of Physical Activity and Health (JPAH) showed an increase in energy expenditure and an increase in heart rate and blood pressure. But a separate study in JPAH, as well as research published in Obesity, showed no significant change in either of these health components.  The use of exercise furniture may affect productivity as well as health. In a review of twelve studies that appeared in Occupational and Environmental Medicine in 2019, treadmill and cycling workstations were found to require more physical activity than sit-stand workstations, with a greater potential for health benefits. In addition, use of the treadmill and cycling workstations increased arousal and decreased boredom. However, motor task performance (for example, the speed and accuracy of typing, mouse pointing, and combined keyboard/mouse tasks) suffered during use of the treadmill desk and under-the-desk cycle when compared to a sit-stand desk. The researchers’ analysis suggested that because treadmill workstations require users to stabilize gait and posture, the fine motor skills required for keyboarding, mouse pointing, and typing are adversely affected. Similar performance decrements when using a treadmill desk were identified in research published in Human Factors and JPAH in 2009. A study published in PLoS ONE in 2015 showed a decline in cognitive tasks such as recall, memory, and concentration, as well as a decline in typing speed and accuracy, while walking on the treadmill. In addition, some studies have found that mousing and keying can be more difficult while moving on a treadmill, resulting in increased errors and tension in the hands.
Are “Active Workstations” the Solution to Excessive Sitting?
Exercising Judgment with Office Furniture
the Synergist
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Disadvantages of being unacclimatized:
  • Readily show signs of heat stress when exposed to hot environments.
  • Difficulty replacing all of the water lost in sweat.
  • Failure to replace the water lost will slow or prevent acclimatization.
Benefits of acclimatization:
  • Increased sweating efficiency (earlier onset of sweating, greater sweat production, and reduced electrolyte loss in sweat).
  • Stabilization of the circulation.
  • Work is performed with lower core temperature and heart rate.
  • Increased skin blood flow at a given core temperature.
Acclimatization plan:
  • Gradually increase exposure time in hot environmental conditions over a period of 7 to 14 days.
  • For new workers, the schedule should be no more than 20% of the usual duration of work in the hot environment on day 1 and a no more than 20% increase on each additional day.
  • For workers who have had previous experience with the job, the acclimatization regimen should be no more than 50% of the usual duration of work in the hot environment on day 1, 60% on day 2, 80% on day 3, and 100% on day 4.
  • The time required for non–physically fit individuals to develop acclimatization is about 50% greater than for the physically fit.
Level of acclimatization:
  • Relative to the initial level of physical fitness and the total heat stress experienced by the individual.
Maintaining acclimatization:
  • Can be maintained for a few days of non-heat exposure.
  • Absence from work in the heat for a week or more results in a significant loss in the beneficial adaptations leading to an increase likelihood of acute dehydration, illness, or fatigue.
  • Can be regained in 2 to 3 days upon return to a hot job.
  • Appears to be better maintained by those who are physically fit.
  • Seasonal shifts in temperatures may result in difficulties.
  • Working in hot, humid environments provides adaptive benefits that also apply in hot, desert environments, and vice versa.
  • Air conditioning will not affect acclimatization.
Acclimatization in Workers