Sitting for extended periods can have detrimental effects on your health. The narrative unfolds in 1950s London, the U.K., where scientists explored the potential disparity in heart disease risk between bus drivers and bus conductors. Their findings revealed that bus drivers faced a higher likelihood of developing heart disease compared to bus conductors, with rates of 2.7 cases per 1,000 bus drivers per year and 1.9 cases per 1,000 bus conductors per year, respectively. Despite sharing the same workspace, bus drivers, characterized by prolonged periods of sedentary behavior, exhibited greater susceptibility to heart disease than their more physically active counterparts, the bus conductors. This observation underscores the adverse impact of prolonged sitting on heart health.

Follow-up research has consistently demonstrated the adverse effects of a sedentary lifestyle on health, elevating the risks of obesity, diabetes, and premature mortality. Adding to this list in September was a concerning revelation: prolonged sitting is now linked to an elevated risk of dementia compared to those with more active lifestyles. Notably, regular exercise has not proven effective in mitigating this increased risk. Individuals who spend more than 10 hours a day sitting experience a heightened vulnerability to dementia.

Published in the Journal of the American Medical Association (JAMA), the study meticulously tracked the behaviors of 49,941 individuals aged 60 and above for almost seven years. Rather than relying on surveys, participants were equipped with smartwatch-like accelerometers on their wrists, enabling continuous monitoring of their daily movements. The collected week's worth of data underwent analysis employing an artificial intelligence (AI) algorithm, precisely gauging the duration of participants' sedentary behavior during waking hours.

At the beginning of the study, none of the participants exhibited signs of dementia. However, over the subsequent seven years, some individuals received a dementia diagnosis. Those who spent more than 10 hours a day sitting faced an 8 percent higher risk of dementia compared to their counterparts with less than 10 hours of daily sitting. Alarmingly, the risk escalated significantly for those who sat for 12 hours a day, resulting in a staggering 63 percent increase in the likelihood of developing dementia. Even incorporating exercise or intermittent breaks from sitting did not mitigate the heightened risk if total sitting time exceeded 10 hours. The crucial factor in risk reduction was observed to be the reduction of overall sitting time, as evidenced by individuals who sat for 9.5 hours a day, showing no significant increase in the risk of dementia.

While this study does not establish a definitive cause-and-effect relationship, there is substantial evidence suggesting that prolonged periods of sitting can have adverse effects on health. When you sit for extended durations, your hip and leg muscles, the largest muscles in your body, remain immobilized. This inactivity hampers blood circulation and diminishes energy expenditure. Reduced energy levels lead to elevated levels of glucose and fat in the blood, posing a health risk. Consequently, the more time spent sitting, the higher the susceptibility to various diseases. Let’s prioritize moving more and sitting less. The principles of a healthy lifestyle are simple but the challenge lies in their implementation.

Jeong Jae-hoon is a food writer and pharmacist. He covers a variety of subjects, including trends in food, wellness and medications. This column was originally published in Korean in Joongang Ilbo on Nov. 9, 2023. – Ed.