Trade the Chair for Fresh Air: Study Explores Link Between Sitting Time and Cardio Health

Summary: Those who sit for six or more hours a day are at a substantially increased risk for heart disease and early death.

Source: Simon Fraser University

New research is adding further weight to the argument that prolonged sitting may be hazardous to your health.

An international study surveying more than 100,000 individuals in 21 countries found that people who sat for six to eight hours a day had a 12–13 percent increased risk for early death and heart disease, while those who sat for more than eight hours daily increased that to a sobering 20 percent.

The study, co-led by Simon Fraser University health sciences professor Scott Lear and Wei Li of Beijing’s Chinese Academy of Medical Sciences, is published today in the journal JAMA Cardiology.

Their research followed individuals over an average of 11 years and determined that high amounts of sitting time were associated with increased risk of early death and cardiovascular disease. While sitting was problematic in all countries, it was especially so in low-income and lower-middle-income countries.

“The overarching message here is to minimize how much you sit,” says Lear. “If you must sit, getting in more exercise during other times of the day will offset that risk.”

Not surprisingly, those who sat the most and were the least active had the highest risk—up to 50 percent—while those who sat the most but were also the most active had a substantially lower risk of about 17 percent.

Not surprisingly, those who sat the most and were the least active had the highest risk—up to 50 percent—while those who sat the most but were also the most active had a substantially lower risk of about 17 percent. Image is in the public domain

“For those sitting more than four hours a day, replacing a half hour of sitting with exercise reduced the risk by two percent,” Lear notes. “With only one in four Canadians meeting the activity guidelines there’s a real opportunity here for people to increase their activity and reduce their chances of early death and heart disease.”

The study found a particular association in lower income countries, leading researchers to speculate that it may be because sitting in higher income countries is typically associated with higher socio-economic status and better paying jobs.

Clinicians should focus on less sitting and more activity as it’s a low-cost intervention that can have enormous benefit, Lear notes.

But while clinicians need to get the message out about countering sitting with activity, individuals need to better assess their lifestyles and take their health seriously, Lear adds. “Our study found that a combination of sitting and inactivity accounted for 8.8 percent of all deaths, which is close to the contribution of smoking” (10.6 percent in Lear and Li’s study). “It’s a global problem that has a remarkably simple fix. Scheduling time to get out of that chair is a great start.”

About this cardiovascular disease research news

Author: Press Office
Source: Simon Fraser University
Contact: Press Office – Simon Fraser University
Image: The image is in the public domain

OriginalResearch: Closed access.
“Association of Sitting Time With Mortality and Cardiovascular Events in High-Income, Middle-Income, and Low-Income Countries” by Sidong Li et al. JAMA Cardiology


Abstract

Association of Sitting Time With Mortality and Cardiovascular Events in High-Income, Middle-Income, and Low-Income Countries

Importance

High amounts of sitting time are associated with increased risks of cardiovascular disease (CVD) and mortality in high-income countries, but it is unknown whether risks also increase in low- and middle-income countries.

Objective

To investigate the association of sitting time with mortality and major CVD in countries at different economic levels using data from the Prospective Urban Rural Epidemiology study.

Design, Setting, and Participants

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This population-based cohort study included participants aged 35 to 70 years recruited from January 1, 2003, and followed up until August 31, 2021, in 21 high-income, middle-income, and low-income countries with a median follow-up of 11.1 years.

Exposures

Daily sitting time measured using the International Physical Activity Questionnaire.

Main Outcomes and Measures

The composite of all-cause mortality and major CVD (defined as cardiovascular death, myocardial infarction, stroke, or heart failure).

Results

Of 105,677 participants, 61,925 (58.6%) were women, and the mean (SD) age was 50.4 (9.6) years. During a median follow-up of 11.1 (IQR, 8.6-12.2) years, 6233 deaths and 5696 major cardiovascular events (2349 myocardial infarctions, 2966 strokes, 671 heart failure, and 1792 cardiovascular deaths) were documented. Compared with the reference group (<4 hours per day of sitting), higher sitting time (≥8 hours per day) was associated with an increased risk of the composite outcome (hazard ratio [HR], 1.19; 95% CI, 1.11-1.28; Pfor trend < .001), all-cause mortality (HR, 1.20; 95% CI, 1.10-1.31; Pfor trend < .001), and major CVD (HR, 1.21; 95% CI, 1.10-1.34; Pfor trend < .001).

When stratified by country income levels, the association of sitting time with the composite outcome was stronger in low-income and lower-middle–income countries (≥8 hours per day: HR, 1.29; 95% CI, 1.16-1.44) compared with high-income and upper-middle-income countries (HR, 1.08; 95% CI, 0.98-1.19; Pfor interaction = .02). Compared with those who reported sitting time less than 4 hours per day and high physical activity level, participants who sat for 8 or more hours per day experienced a 17% to 50% higher associated risk of the composite outcome across physical activity levels; and the risk was attenuated along with increased physical activity levels.

Conclusions and Relevance

High amounts of sitting time were associated with increased risk of all-cause mortality and CVD in economically diverse settings, especially in low-income and lower-middle–income countries. Reducing sedentary time along with increasing physical activity might be an important strategy for easing the global burden of premature deaths and CVD.

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