Sitting for long periods of time may be more dangerous than we think, according to a recent study conducted by researchers from the University of California-San Diego. The study found that older women who sat for 11.7 hours or more daily had a 30% higher risk of death, even if they engaged in vigorous exercise.
The study, led by Steve Nguyen, a postdoctoral fellow at the UC San Diego Herbert Wertheim School of Public Health and Human Longevity Science, analyzed data collected from 6,489 women aged 63 to 99. The participants wore monitors to track their daily activity and sitting time for up to a week. The researchers also monitored the participants for eight years to track any deaths.
The data used in the study was originally collected as part of a larger long-term national project called the Women’s Health Initiative (WHI), which began in 1991 and is still ongoing today. This report is the first to utilize a machine-learned algorithm called CHAP to analyze the relationship between sitting time and the risk of premature death.
Nguyen explains that sedentary behavior, defined as any waking behavior involving sitting or reclining with low energy expenditure, is detrimental to health. The CHAP algorithm, developed using machine learning, accurately distinguishes between standing and sitting, providing a more accurate assessment of total sitting time and usual sitting bout durations.
The negative effects of sedentary behavior include decreased muscle contractions, blood flow, and glucose metabolism. When sitting, blood flow throughout the body slows down, leading to decreased glucose uptake and reduced muscle activity. Surprisingly, exercise does not reverse these negative effects. Regardless of the amount of exercise performed, if excessive sitting is involved, the risk remains the same.
Prof. LaCroix explains that even if someone takes a brisk long walk for an hour but sits for the rest of the day, they will still experience the negative effects on their metabolism. The risk of death increases when sitting for about 11 hours per day, especially if sitting for long periods without breaks. Prof. LaCroix recommends getting up once an hour or every 20 minutes to stand for a little while, as this can help mitigate the risks associated with prolonged sitting.
It’s important to note that not all sitting is the same. Nguyen suggests that sedentary behavior in certain contexts, such as sitting while studying a new language, may not have the same negative impact on health. He is currently conducting research on protein signatures tied to physical activity and their relationship to dementia.
While changing sedentary behavior can be challenging, Prof. LaCroix emphasizes the need for modifications. She believes that culturally, we have become too attracted to activities that involve sitting for long periods, such as watching TV or scrolling through social media. By reducing our attraction to these activities, we can reverse the negative effects of prolonged sitting.
The study, published in the Journal of the American Heart Association, highlights the importance of avoiding sedentary behavior and incorporating regular breaks from sitting into our daily routines. By doing so, we can reduce the risk of premature death and improve our overall health and well-being.
