Is Sitting All Day Harming Your Health?

Endocrinologist Dr. Rekha Kumar explains the health risks of spending too much time sitting.

People sitting at desks
People sitting at desks

Are you sitting right now? If so, you may want to stand up. More and more studies show that sitting for prolonged periods poses a serious risk to your health.

Yet 1 in 4 Americans spends at least eight hours a day sitting, according to the Centers for Disease Control and Prevention, and the average office worker sits for as many as 15 hours a day including their commute, desk time, mealtime, and after-hours spent on the couch.

To find out how all this sitting affects people’s health, Health Matters spoke with Dr. Rekha B. Kumar, an attending endocrinologist at NewYork-Presbyterian/Weill Cornell Medical Center and an assistant professor of medicine at Weill Cornell Medicine, about the dangers of prolonged sitting and what you can do to avoid it.

Portrait of Dr. Rekha Kumar

Dr. Rekha B. Kumar

What are the biggest health risks of sitting?
Not moving! A body at rest can lead to serious health problems like obesity, diabetes, high cholesterol, high blood pressure, and even heart disease and stroke.

Sitting has been called the new smoking. Can it really be compared to smoking?
The cumulative damage of sitting for prolonged periods of time, over several years, can be equated to the negative health consequences of smoking. Sitting, like smoking, can be correlated with negative health outcomes in every organ system from our heads (depression, stroke) down to our toes (blood clots, nerve problems) and even our skin (fungal infections, pressure sores).

Does sitting all day erase the benefits of exercise as one recent study suggested?
The study, published in the Journal of Applied Physiology, found that sitting for more than 13 hours a day may negate the benefits of exercise, which makes me reconsider the concept that a little gym time will be the antidote to our modern sedentary lifestyles. It really suggests that some continuous movement, like getting up often and walking around for a few minutes, may be healthier for how our bodies need to optimally function.

Are there simple ways to add more movement to your day?
I recommend getting up once an hour, walking around for at least five minutes, doing some light stretching, and introduce some type of resistance exercise throughout the day if your job requires prolonged sitting. Just a few examples are 10 squats, 10 triceps dips on a chair, and wall pushups. These are things that can be done at work.

Animation of how to do squats
Animation of how to do tricep dips
animation of how to do wall push ups

How does sitting for prolonged periods affect your overall health?
It is not a surprise that many of the medical conditions that we see in people who sit for prolonged periods of time are similar to what we see in patients who have obesity-related diabetes, high cholesterol, arthritis, joint pain, and high blood pressure. Sitting does not cause these diseases, but prolonged sitting means less time moving and less work for our muscles, which has implications of how we metabolize nutrients.

What happens to your metabolism if you spend all day sitting?
It slows down. A sedentary lifestyle, which includes prolonged sitting, means less work done by our muscles. Active muscles equate with higher metabolism and better blood sugar management. A healthy metabolic rate and appropriate use of nutrients by our muscles keeps our bodies in a healthy balance. Once this deteriorates, other parts of our health are affected, including cholesterol and fat metabolism, blood pressure, and joint mobility.

Does your metabolism slow down after a certain number of hours? If so, how many?
Metabolism slows with a decline in lean muscle mass. Lean muscle mass declines with prolonged sitting. We can’t say how many hours it takes to slow down metabolism since metabolism varies from person to person, and genetics, diet, exercise, and body composition also play a part. The bottom line is: The more you move, the more you’ll boost your metabolism.

How often do you need to get up to prevent your metabolism from slowing down?
We should aim to get up at least once an hour, but ideally we should try to move our bodies throughout the day. The concept of LISS (low-intensity steady state) exercise — walking at a brisk pace or swimming some laps — comes from the noted benefits of continuous movement (versus HIIT, high-intensity interval training).

This is the first in a series on the health impacts of sitting.

Rekha B. Kumar, M.D., is an attending endocrinologist at NewYork-Presbyterian/Weill Cornell Medical Center and an assistant professor of medicine at Weill Cornell Medicine. She specializes in the diagnosis and treatment of endocrine disorders, including obesity/weight management and thyroid disorders. She is also the medical director of the American Board of Obesity Medicine.

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