FITNESS MYTH: OCCUPATIONAL PHYSICAL ACTIVITY IS EXERCISE
Common amongst my clients and friends who have physically active jobs is the idea that their job is “exercise.” As a first world society continues to advance with technology, and it’s population becomes increasingly sedentary, one could see the derivative of the idea. Indeed these jobs require a lot of movement that results in a higher total daily energy expenditure (TDEE), but TDEE is not the determinant of whether or not an activity is exercise. One of the main purposes of leisure time physical activity (LTPA) (formal exercise) is to increase markers of health and to consequently prevent illness and injury. Within this article I will demonstrate if occupational physical activity (OPA) meets these criterion.
Being physically active is great, and this article in no way intends to deter readers from being active and busy throughout their day. What should be understood is whether or not OPA offers the same health benefits as LTPA so that well-intentioned persons aren’t naively excluding themselves from these benefits.
Petermann-Rocha et al. (2019) produced a study that investigated whether there was a difference in health markers between people who regularly participated in LTPA and those who solely performed OPA. It was found that the LTPA group lowered odds for every major cardiovascular risk factor including obesity, central obesity, metabolic syndrome, hypertension and diabetes. In contrast, the group who solely performed OPA only saw a decrease to their odds for diabetes. Again, this may be counterintuitive for many people who feel like they are doing a lot of hard work throughout the day. Why doesn’t this type of physical activity (PA) produce the same outcomes as LTPA?
In an effort to explain the mechanisms as to why OPA doesn’t offer the same health benefits as LTPA, Holterman et al. (2018) produced an article explaining the major physiological differences. One of the first reasons being that OPA is too long and too low. In order to improve cardiovascular fitness, PA needs to be performed above 60-80% of our maximum aerobic capacity. Given the intensity level, this can only be sustained for shorter durations (especially compared to an 8 hour work day). OPA is oftentimes seen to be performed around 30-35% of our maximum aerobic capacity and for much longer durations than seen in traditional LTPA. These longer durations have actually been studied to impair cardiovascular health (Holterman et al., 2018). OPA increases our 24-hour hearth rate. If this is seen over prolonged periods of time it becomes a risk factor for mortality and cardiovascular disease (CVD). LTPA does not have this effect.
Common to much OPA is maintaining a static posture while performing the tasks associated to with the job. In these instances blood pressure is increased and remains elevated even after the work day. Elevated blood pressure is also a risk factor for CVD. The shorter durations of LTPA allow for our blood pressure to return to baseline levels and do not increase our 24-hour blood pressure (Holterman et al., 2018).
Whenever I build a LTPA plan for a client I take special consideration to their recovery. The assigned exercises are spaced out in a manner that allows for the athlete’s muscles to heal and adapt to the exercise stimulus that was performed. OPA doesn’t always offer workers enough time to fully recover from what they did the day before or even within the work day. This leads to fatigue, exhaustion and may also increase the risk for CVD (Holterman et al., 2018). Another benefit of LTPA is that we can control many aspects of the activity. A majority of my Master’s program was dedicated to understanding the body and how we can manipulate variables in order to elicit specific outcomes. Whether this be through clothing, exercise selection, rest times, periodization, nutrition or any other of the many variables that have to be considered when programming athletes. While LTPA offers substantial control, OPA does not. 50% of the world’s population works outside where they cannot control the climate. This leads to an increased risk for heat stress and stroke as well as CVD (Holterman et al., 2018). All of these stressors and factors associated with OPA can lead to increased inflammatory markers such as CRP. Sustained inflammation is believed to be a pathway for atherosclerosis and other CVDs (Holterman et al., 2018).
Given the cited research, OPA does not increase cardiovascular health and can actually be a detriment to it. But what about the musculoskeletal benefits? There are certain jobs that require heavy objects to be moved in a manner similar to movements seen in the weight room. But, similar to our cardiorespiratory fitness, certain levels of difficulty and/or volume (coupled with proper break times) of the task need to be performed in order to produce physiological improvements (Haff & Triplett, 2016). For example; lifting a 25 lbs box fifty times throughout the day may, at first, produce an increase to the workers strength and/or hypertrophy. But if this same task is repeated every day then the worker will no longer perceive it to be difficult because of the adaptation. OPA lacks progressive overload, proper recovery and worker control over the safety of the movement. Within a gym, an athlete could progress by increasing the weight or total repetitions performed. Additionally, many of the movements within a gym setting have a lower associated risk due to user control and equipment that allows us to maintain safe lifting form. As stated before, workers likely won’t have this option so the task reaches a point where it is no longer challenging . Instead of progressing, continually repeating this motion with inadequate recovery increases the likelihood of an overuse injury (Sogaard & Sjogaard, 2017). This was demonstrated in a client who was a painter. His company did not use a spraying tool so he spent his days rolling and brushing, usually with the same hand. In the beginning this may have been an activity that produced helpful increases to the musculature of his forearm, but overtime it caused an overuse injury to the musculature involved with gripping and moving his wrist.
Sogaard and Sjogaard (2017) wrote about how PA can be both a cause and a cure for muscular pain. Movement can create, prevent and cure muscular injuries depending on the context and application. As seen in the painter, this type of movement led to an injury. But another type of movement (physical therapy) helped to cure it, and finally other movements were used to prevent it from happening again. This is all to demonstrate that all movements aren’t created equal and cannot be lumped together under the umbrella of “exercise” simply because it is a PA.
In order to see all the health benefits associated with exercise, we need to perform high intensity exercises for shorter durations. The movements that we choose to perform for LTPA need to be centered around our goals, allow for proper break times and recovery and be structured in a manner that allows for progressive overload. Doing so has been shown to produce significant reductions to every major cardiovascular risk factor and can also produce a physique that we are happy with. The inability to follow this structure during OPA not only disqualifies it as a form of “exercise,” but may also be a significant detriment to our health as a standalone movement modality (Holterman et al., 2018).
Haff, G. & Triplett, N. (2016). Essentials of strength and conditioning (4th Edition). Champaign, IL: Human Kinetics.
Holtermann, A., Krause, N., van der Beek, A. J., & Straker, L. (2018). The physical activity paradox: Six reasons why occupational physical activity (OPA) does not confer the cardiovascular health benefits that leisure time physical activity does. British Journal of Sports Medicine, 5(2), 149-150.
Petermann-Rocha, F., Brown, R. E., Diaz-Martinez, X., Leiva, A. M., Martinez, M. A., Poblete-Valderrama, F., Garrido-Mendez, A., Matus-Castillo, C., Luarte-Rocha, C., Salas-Bravo, C., Troncoso-Pantoja, C., Garcia-Hermoso, A., Ramirez-Velez, R., Vasquez-Gomez, J. A., Rodriguez-Rodriguez, F., Alvarez, C., & Celis-Morales, C. (2019). Association of leisure time and occupational physical activity with obesity and cardiovascular risk factors in Chile. Journal of Sports Sciences, 37(22), 2549-2559.
Sogaard, K., & Sjogaard, G. (2017). Physical activity as cause and cure of muscular pain: Evidence of underlying mechanisms. Exercise & Sport Sciences Reviews, 45(3), 136-145.