People who spend most of their work time sitting have 16% more chance of dying earlier than normal, suggest scientists, with their risk of death from cardiovascular disease being 34% higher than those who don’t sit much while working.
The Washington Post reports that the study, conducted by scientists in Taiwan, involved 481 688 participating workers, 20 and older (average age 39), who were tracked for about 13 years. None had a CVD diagnosis when they joined the study group.
The research, published in JAMA Network Open, also found that those whose work included a combination of time sitting as well as time standing or moving around, had less risk of early death than those who were regular non-sitters.
Those who mostly sat at work and did little physical activity on their own time, however, were able to lower their risk for early death to the level of non-sitters by upping their leisure-time physical activity by just 15 to 30 minutes a day.
The study’s findings “help to strengthen the increasingly accumulating evidence linking a sedentary lifestyle and health risks”, wrote the researchers, led by a team from Taipei Medical University.
Their findings suggest that beneficial workplace changes could include the addition of standing tables, activity-permissive work stations, more frequent breaks for employees, designated workplace areas for physical activity, company-sponsored group activities and gym membership benefits.
Others, including the Mayo Clinic, recommend taking a break from sitting every 30 minutes, standing up when talking on the phone and joining colleagues for walking meetings rather than sitting in a conference room.
Study details
Occupational Sitting Time, Leisure Physical Activity, and All-Cause and Cardiovascular Disease Mortality
Wayne Gao, Mattia Sanna, Yea-Hung Chen, et al.
Published in JAMA Network Open on 19 January 2024
Key Points
Question What are the health outcomes associated with prolonged occupational sitting in the context of various levels of physical activity among apparently healthy individuals?
Findings In this cohort study involving 481 688 individuals over a mean follow-up period of 12.85 years, individuals who predominantly engaged in sitting at work exhibited a higher risk of mortality from all causes (16%) and cardiovascular disease (34%) compared with those who predominantly did not sit, even after adjusting for sex, age, education, smoking, drinking, and body mass index. Individuals who predominantly sit at work would need to engage in an additional 15 to 30 minutes of physical activity per day to mitigate this increased risk and reach the same level of risk as individuals who predominantly do not sit at work.
Meaning These findings suggest that reducing prolonged sitting in the workplace and/or increasing the volume or intensity of daily physical activity may be beneficial in mitigating the elevated risks of all-cause mortality and cardiovascular disease associated with prolonged occupational sitting.
Abstract
Importance
For the first time, the 2020 World Health Organisation guidelines on physical activity recommended reducing sedentary behaviours owing to their health consequences. Less is known on the specific association of prolonged occupational sitting with health, especially in the context of low physical activity engagement.
Objective
To quantify health risks associated with prolonged occupational sitting and to determine whether there is a certain threshold of physical activity that may attenuate it.
Design, Setting, and Participants
This prospective cohort study included participants in a health surveillance program in Taiwan who were followed-up between 1996 and 2017. Data on occupational sitting, leisure-time physical activity (LTPA) habits, lifestyle, and metabolic parameters were collected. Data analysis was performed in December 2020.
Main Outcomes and Measures
The all-cause and cardiovascular disease (CVD) mortality associated with 3 occupational sitting volumes (mostly sitting, alternating sitting and non-sitting, and mostly non-sitting) were analysed applying multivariable Cox regression models to calculate the hazard ratios (HRs) for all participants and by subgroups, including 5 LTPA levels and a personal activity intelligence (PAI)–oriented metric. Deaths occurring within the initial 2 years of follow-up were excluded to prevent reverse causality.
Results
The total cohort included 481 688 participants (mean [SD] age, 39.3 [12.8] years; 256 077 women [53.2%]). The study recorded 26 257 deaths during a mean (SD) follow-up period of 12.85 (5.67) years. After adjusting for sex, age, education, smoking, drinking, and body mass index, individuals who mostly sat at work had a 16% higher all-cause mortality risk (HR, 1.16; 95% CI, 1.11-1.20) and a 34% increased mortality risk from CVD (HR, 1.34; 95% CI, 1.22-1.46) compared with those who were mostly non-sitting at work. Individuals alternating sitting and non-sitting at work did not experience increased risk of all-cause mortality compared with individuals mostly non-sitting at work (HR, 1.01; 95% CI, 0.97-1.05). For individuals mostly sitting at work and engaging in low (15-29 minutes per day) or no (<15 minutes per day) LTPA, an increase in LTPA by 15 and 30 minutes per day, respectively, was associated with a reduction in mortality to a level similar to that of inactive individuals who mostly do not sit at work. In addition, individuals with a PAI score exceeding 100 experienced a notable reduction in the elevated mortality risk associated with prolonged occupational sitting.
Conclusions and Relevance
As part of modern lifestyles, prolonged occupational sitting is considered normal and has not received due attention, even though its deleterious effect on health outcomes has been demonstrated. In this study, alternating between sitting and non-sitting at work, as well as an extra 15 to 30 minutes per day of LTPA or achieving a PAI score greater than 100, attenuated the harms of prolonged occupational sitting. Emphasising the associated harms and suggesting workplace system changes may help society to denormalise this common behaviour, similar to the process of denormalising smoking.
See more from MedicalBrief archives:
Sleeping beats sitting when it comes to heart health: UK study
Sitting eight hours a day linked to increased health risks – Latin American study
Sitting for hours can increase CVD risk, hasten death – cohort study
Just a few minutes of light intensity exercise linked to lower death risk in older men