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Being sedentary can carry many health risks, including early death. Catherine Falls Commercial/Getty Images
  • Following a sedentary lifestyle can have negative effects on a person’s health and increase their risk for serious health conditions.
  • Researchers from the University of California San Diego have linked sedentary behavior to an increased mortality risk in older women.
  • Scientists found the heightened death risk continued even if study participants participated in low or high amounts of moderate-to-vigorous intensity physical activity.

According to researchers, more than 80% of all jobs in the U.S. require a person to be sitting for long periods.

Past studies show that people who are mainly sedentary at work have more fatigue, increased neck and back pain, and more depression.

Additionally, following a sedentary lifestyle may increase a person’s risk for health conditions like cardiovascular disease, type 2 diabetes, high blood pressure, osteoporosis, and certain cancers including breast cancer and prostate cancer.

Now, a new study recently published in the Journal of the American Heart Association has linked sedentary behavior to an increased mortality risk in older women.

The study — conducted by researchers at the University of California San Diego — also found the heightened death risk continued even if study participants participated in low or high amounts of moderate-to-vigorous intensity physical activity.

According to Dr. Steve Nguyen, a postdoctoral fellow at the Herbert Wertheim School of Public Health and Human Longevity Science at the University of California San Diego and the first author of this study, they decided to study the potential link between sedentary behavior and mortality risk because people are sedentary for much of the time that we are awake whether we are watching TV, using our screen-based devices, or doing other common activities.

The researchers also decided to focus on older women ages 63 to 99 for this study.

“The Women’s Health Initiative Program, which this study (OPACH) is a part of, was started in the 1990s to overcome decades of health research that did not include women. Our study is unique because it is one of few large studies where older women wore activity monitors and were then followed for up to 10+ years for health outcomes,” Dr. Nguyen told Medical News Today.

“When studying mortality, it is important to focus on the age groups (that) experience death most often, which is why the focus on older women is so appropriate. As we state in the paper, it is important to replicate these findings in middle-aged and older groups inclusive of men. We also work in other studies and collaborate with other researchers to study sedentary behavior in other groups,” he added.

For this study, Dr. Nguyen and his team analyzed sitting and daily activity data for about 6,500 older women. The participating women wore hip devices for up to seven days that collected the activity data. The women were then followed for a median of eight years to determine their mortality outcomes.

This study is also reportedly the first to use a machine-learned algorithm called CHAP to study the participants’ total sitting time and length of sitting periods to mortality risk.

“The CHAP (Convolutional neural network Hip Accelerometer Posture) AI algorithm can estimate sedentary behavior using data from hip-worn activity monitors, and importantly, considers posture, which is a major component of sedentary behavior — defined as low energy expenditure while sitting or reclining when awake,” Dr. Nguyen explained.

“Common methods of calculating sedentary time from activity monitors focused on movement intensity cutpoints which do not capture posture and could include standing, which is a less risky behavior. By using the CHAP algorithm in our study, we can more accurately examine the link between sedentary behavior and mortality,” he said.

At the conclusion of the study, the research team found that older women who sat for 11.7 hours or more each day had an increased risk of dying by 30%.

“What we find noteworthy about our study and the results, however, was that one, it was the first study to apply the CHAP algorithm to calculate sedentary behavior. Two, the risk starts climbing at ~11 hours per day which helps us to understand how many hours of sitting is risky in older women,” Dr. Nguyen said.

Three, there is a small but measurable additional risk for women who sat for long periods at a time more often. And four, women who sat more had higher mortality risks regardless if they had low or high amounts of moderate-to-vigorous intensity physical activity,” he added.

Additionally, the scientists found this increased mortality rate did not change if a woman participated in low or high amounts of moderate-to-vigorous intensity physical activity.

“This is significant because sedentary behavior is not just the ‘other side of the coin’ for physical activity. A person can go for a brisk walk every day for an hour to sweat and get their heart rate up, but still sit for the rest of the day and accumulate the negative effects.”
— Dr. Steve Nguyen

MNT also spoke with Dr. Cheng-Han Chen, a board certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, about this study.

Dr. Chen said this study affirmed a lot of what we already know, which is that being sedentary and sitting still for long periods is not good for your health.

“What was surprising was that sprinkling in brief periods of moderate activity throughout the day didn’t seem to be able to negate the harmful effects of sitting still for long periods of time. And that’s in distinction to other studies that we’ve talked about throughout the last few months that small amounts of exercise throughout the day did seem helpful for health,” he continued.

Dr. Chen recommended that readers get up every 30 minutes of sitting to walk and move around for four to five minutes.

“It’s not the sitting still that hurts you, it’s the not moving around that hurts you. When you’re sitting still, you’re not doing a lot of the normal physical activity that your body is designed to do. In exercising and moving around, your organs and tissues are learning to become more efficient and perform better. And when they are able to work better and be better at metabolism, you improve a lot of these conditions that end up being risk factors for heart disease.”
— Dr. Cheng-Han Chen

“So moving around, making your muscles efficient, utilizing your organs is helpful to keep you away from having high blood pressure, high cholesterol, diabetes, or obesity,” Dr. Chen added.