By Seema Gupta, MD, MSPH
Clinical Assistant Professor, Department of Family and Community Health, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV
A large prospective cohort study demonstrated that prolonged sitting at work increases the risk for all-cause and cardiovascular disease mortality, but even short periods of physical activity throughout the day may help mitigate the negative effects.
Gao W, Sanna M, Chen Y-H, et al. Occupational sitting time, leisure physical activity, and all-cause and cardiovascular disease mortality. JAMA Netw Open 2024;7:e2350680. doi:10.1001/jamanetworkopen.2023.50680.
Over the past few decades, there has been a decline in work-related physical activity across developed nations primarily as a result of various technological advances. However, similar changes in the macro-environment, such as in transportation, communication, and declining activity in the home, have led to an ever-increasing sedentary lifestyle.1 Yet, it is well recognized that regular physical activity is a known protective factor for the prevention and management of several non-communicable diseases, including cardiovascular disease (CVD), various cancers, obesity, and type 2 diabetes. It also is associated with improvements in brain health, decreased falls, and benefits in arthritis, as well as during pregnancy and the peripartum period.2 Finally, regular physical activity is a well-established factor for lowering the risk of all-cause mortality and improving overall quality of life.
For this reason, in 2020, the World Health Organization issued guidelines on physical activity to reduce sedentary behaviors.3 These guidelines are intended for all populations and age groups, ranging from 5 years to 65 years and older, regardless of gender, cultural background, or socioeconomic status, and remain relevant for people of all abilities.
Studies have looked at whether leisure-time physical activity (LTPA) can reduce or eliminate the risks associated with prolonged sitting. Authors of a meta-
analysis demonstrated that approximately 30 to 40 minutes of moderate- to vigorous-intensity physical activity per day would eliminate the prolonged sitting-associated all-cause and CVD mortality risk.4 However, the data do not specify if individuals would derive the same benefit in the setting of occupational prolonged sitting, which may be valuable to employers and society at-large.
Gao et al conducted a prospective cohort study to quantify health risks associated with prolonged sitting on the job and examined whether a certain threshold of physical activity may attenuate that risk. Study participants included 481,688 adults (mean age, 39 years; 53% women) in a health surveillance program in Taiwan followed between 1996 and 2017. The researchers collected data from study participants on occupational sitting, LTPA habits, lifestyle, and metabolic parameters.
During an average follow-up of almost 13 years, 26,257 participants died; more than half (57%) of the deaths occurred in individuals who mostly sat at work. There were 5,371 CVD-related deaths, with 60% occurring in the mostly sitting group.
In multivariate analysis adjusted for sex, age, education, smoking, drinking, and body mass index, study participants who mostly sat at work had a 16% higher risk of dying of any cause (hazard ratio [HR], 1.16; 95% confidence interval [CI], 1.11-1.20) and a 34% increased risk of dying of CVD (HR, 1.34; 95% CI, 1.22-1.46) compared with those who mostly did not sit at work. Those workers who mostly alternated between sitting and not sitting at work were not at increased risk of all-cause mortality compared with individuals who mostly did not sit at work (HR, 1.01; 95% CI, 0.97-1.05). Among individuals who mostly sat at work and engaged in low (15-29 minutes) or no (< 15 minutes) daily LTPA, increasing activity by 15 and 30 minutes per day, respectively, lowered the risk for mortality to a level similar to that of inactive individuals who mostly did not sit at work.
COMMENTARY
As developed countries become more advanced, our lifestyle is becoming more sedentary. Increasingly, accumulating evidence is linking a sedentary lifestyle with health risks and increased all-cause mortality. Perhaps, prolonged sitting at one’s place of work may contribute the most to this health risk. The large prospective cohort study conducted by Gao et al is significant in two ways. First, they found that individuals who mostly sit at work had higher mortality risks than those who mostly do not. Second, they found that alternating between sitting and not sitting at work or increasing physical activity in leisure time can make all the difference.
From a practical standpoint, this means for certain patients with prolonged sitting tasks and with already elevated risks, such as for CVD, it may be prudent to recommend incorporating regular breaks in work settings to alternate between sitting and not sitting. This could even mean having sitting and standing work stations, taking breaks more often, or using stairs instead of an elevator.
Even when that may not be possible, the authors found that participating in an extra 15 to 30 minutes per day of exercise or in more physically intense activities still can compensate for the elevated risks from prolonged sitting at work. It may be time for employers to step up and consider providing opportunities for employees’ physical activities. It would not only keep the workforce healthy but may be good for the bottom line.5
REFERENCES
- Brownson RC, Boehmer TK, Luke DA. Declining rates of physical activity in the United States: What are the contributors? Annu Rev Public Health 2005;26:421-443.
- Singh R, Pattisapu A, Emery MS. US Physical Activity Guidelines: Current state, impact and future directions. Trends Cardiovasc Med 2020;30:407-412.
- World Health Organization. WHO guidelines on physical activity and sedentary behaviour: At a glance. Nov. 25, 2020. https://www.who.int/publications/i/item/9789240014886
- Stamatakis E, Gale J, Bauman A, et al. Sitting time, physical activity, and risk of mortality in adults. J Am Coll Cardiol 2019;73:2062-2072. Erratum in: J Am Coll Cardiol 2019;73:2789.
- Dallmeyer S, Wicker P, Breuer C. The relationship between leisure-time physical activity and job satisfaction: A dynamic panel data approach. J Occup Health 2023;65:e12382.
