Desk-bound workers need additional exercise to counter health impacts of sitting, higher mortality risk - study

Person looking at fitness watch on their wrist
To counteract the increased risk, individuals who sit a lot at work would have to engage in an additional 15 to 30 minutes of physical activity per day to reduce their risk to that of individuals who do not predominantly sit, researchers estimated. Photo credit: Getty Images

By Katia Hetter of CNN

Tired of sitting at that desk all day long? Turns out it's not good for your health either, according to a new study published in JAMA Network Open.

People who predominantly sit at work have a 16 percent higher risk of mortality from all causes, and a 34 percent higher risk of mortality from cardiovascular disease. To counteract the increased risk, individuals who sit a lot at work would have to engage in an additional 15 to 30 minutes of physical activity per day to reduce their risk to that of individuals who do not predominantly sit, researchers estimated.

As I sit here typing, I'm wondering what I should make of these study results. What can desk-bound workers do to reduce elevated health risks from inactivity? Is it better to be active in small amounts each workday, or should we save up for one big block on weekends? And what about those who are already on medications to treat obesity, diabetes and other chronic illnesses - what should they do? 

I turned to CNN wellness expert Dr Leana Wen, who is an emergency physician and adjunct associate professor at George Washington University. She previously served as Baltimore's health commissioner.

CNN: Are you surprised by the findings in this study - a 16 percent higher mortality from all causes and a 34 percent higher mortality from cardiovascular disease for people who predominantly sit at work?

Dr Leana Wen: I'm not surprised by the gist of the study, though the magnitude of effect is large and certainly should be a call to action.

For years, we have known that prolonged sitting has negative health impacts - that it increases the risk of chronic diseases including obesity, diabetes and cardiovascular death. Studies have also shown that even light activity to break up the periods of prolonged sitting can reduce that risk. One 2023 Columbia University study found that people who engaged in light activity for just five minutes every 30 minutes had an almost 60 percent reduction in blood sugar spikes after a meal. Those who did just one minute of exercise every 30 minutes experienced a drop in blood pressure. 

Importantly, the exercise that people engaged in for that study was not intensive. Rather, it was a slow walk on the treadmill at 1.9 miles per hour, which is slower than most people walk.

Another 2023 study found that replacing 30 minutes of sedentary activity with very light activity like walking or standing led to improvements in key measures, such as body mass index (BMI) and cholesterol levels. Higher-intensity exercise had a bigger benefit, but the key here is that light activity for small periods of time produced a difference, too.

This new JAMA Network Open study is significant because it involves so many participants - more than 480,000 - and researchers followed them over an average time of nearly 13 years. They also adjusted for sex, age, education, smoking and drinking status, and BMI. I think it's remarkable that they found such a pronounced difference in all-cause mortality and especially mortality from cardiovascular disease.

Imagine if there were a medication that could reduce your chance of dying from heart disease significantly. It would be very popular! Or the other way around - what if there was a lifestyle habit that increased people's chance of dying from a heart attack or stroke? People would do a lot to change that habit, as they should when they sit for prolonged periods at work. 

CNN: What can desk-bound workers do to reduce the elevated health risks from inactivity?

Wen: The US Centers for Disease Control and Prevention recommends that adults engage in at least 150 minutes of moderate to high intensity exercise a week. That amounts to about 22 minutes a day, or if people are exercising, say, five times a week, it's about 30 minutes each time. Ideally, people can set aside time to walk briskly, jog, ride a bike, work out on the elliptical machine or otherwise commit time to exercise for at least that amount of time per week.

Many desk workers already engage in some version of these activities, but they can work to increase the duration and intensity of the activities. Instead of walking around the neighborhood once before dinner, what about walking around twice? Instead of going to the gym twice a week, what about three times? Could they park a few blocks farther and walk faster to get to work and back? These small changes can add up.

It really doesn't have to be a huge change: A very small amount of light physical activity during work hours can improve health, according to the studies I cited above. These are sometimes called "exercise snacks." Some things people can do include getting up every 30 minutes or an hour to stretch or walk around their office - or for people who work at home, their home, apartment corridor or yard. They could hold a plank or do jumping jacks. Those with more mobility challenges can still do stretches like side bends and twists in their chair. Practicing breathing exercises that deeply engage the diaphragm could help, too. 

CNN: What about people who haven't done much exercise at all and can't get to 150 minutes a week right away?

Wen: There's good news. A study published last year found that just half of the recommended amount of exercise made a big impact on improving health. While those who met the 150 minutes a week threshold had the most significant benefit, just 75 minutes of moderate-intensity exercise activity per week (which is just about 11 minutes a day) was associated with a 23 percent lower risk of premature death. It also reduced the risk of developing cardiovascular disease and cancer.

To me, the main takeaway is that some exercise is better than none. More is better if that's possible, but people who currently have sedentary lifestyles shouldn't be intimidated. Everyone needs to start with where they are and consider their current level of fitness, their time constraints, the type of job they have and so forth.

If someone is already active, they can increase the frequency and intensity of their exercise regimen. But if someone is not, they can start with the basics and begin walking slowly around their neighborhood. Those time-crunched can try to combine these walks with phone calls. They could work in basic mobility and strength exercises, including those that do not require any additional equipment. And they could incorporate "exercise snacks" into their workday. Perhaps they could set an alarm to get up and walk around and stretch every hour. Simple behavior changes, when done consistently, add up over time. 

CNN: Is it better to be active in small amounts throughout workdays or to save up for one big block on weekends?

Wen: Definitely the former. Prolonged inactivity has health risks. Ideally, people can do both, with periods of more intensive exercise - for instance, riding a bike on weekends and running during the week, in addition to getting up more frequently to break up sitting during the day. But those who are only doing intensive exercise once a weekend should not think that this is enough to counteract the damage that is being done with prolonged sitting during the week.

CNN: And what about those who are already on medications to treat obesity, diabetes and other chronic illnesses - should they also heed these recommendations?

Wen: Yes. Medications do not replace lifestyle changes. People with chronic conditions should of course consult their health care provider to ensure that the fitness regimen is safe and appropriate for them, but improved health won't come from just medications alone. Fitness and physical activity are key components of living healthily and well.