This action is really harmful to the body, but many people do it every day! Solution →

I believe everyone has heard that sitting for a long time is harmful to the body. But how long is considered sitting for a long time? I believe many people are not sure.

Let me give you the answer first: Sitting for a long time is not considered long if you sit for 8 hours. Sitting for more than 90 minutes can be considered long-term sedentary behavior. In other words, the time it takes to sit or lie down and play a few games or watch a movie is already considered long-term sedentary behavior.

However, for the poor workers, after working all day in front of the computer, they just want to lie down and don't want to move at all after get off work. After all, there is endless work to do, and they have to sit on the office chair for 8 hours. After all, after get off work, they just want to let their mind and muscles "lie down". Sitting for a long time is really "forced by life".
How can we stay healthy while having to sit for long periods of time? Today, we invite an orthopedic surgeon to explain in detail.

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How to eliminate the harm of sitting for a long time?

Pay attention to these 3 points

Studies have found that sitting for more than 6 hours a day increases the risk of many diseases , including cancer, cardiovascular disease (including coronary heart disease and stroke), diabetes, kidney disease, suicide, chronic obstructive pulmonary disease, pneumonia (due to solids and liquids), liver and other digestive system diseases, Parkinson's disease, Alzheimer's disease, neurological diseases and musculoskeletal diseases.

"Sitting for a long time" has been listed as one of the top ten killers and causes of disease. There is no need to describe in detail the harm it causes to the body. After all, most workers are forced to sit for a long time due to life pressures. So is there any way to eliminate the harm of sitting for a long time?

1

Correcting sedentary behavior

It is recommended to leave your seat every 30 minutes, even if it is just to get up and get a glass of water, walk around the office, or stand up and work for a while before sitting down again.

If conditions permit, it would be better to do some stretching exercises that are allowed in the office. Today, I recommend several simple and easy stretching exercises that can be done on an office chair. They have a small range of motion and will not affect other people's work. Although the amount of activity is small, it is definitely better than not moving at all.

1. Hip stretch

Working people's hips and lower backs may become tight due to sitting for a long time. This seated stretch can stretch the hips and lower back at the same time.

Sit on the edge of a chair with your feet hip-width apart, cross your ankles over your opposite knees, and press your back forward and down until your chest and abdomen are pressed against your calves and knees.

Image source: Galaxy

2. Lower back release

Rotate sideways in your chair, holding onto the back of the chair with the arm closest to it, and gently twist the front of your body toward the back of the chair. Reach your other arm toward your opposite knee, or as far as you can if you can.

Image source: Galaxy

3. Shoulder opening training

This movement can stretch your shoulders, open your chest, allow more fresh air to enter your lungs, and increase the oxygen uptake of organs throughout the body.

Sit upright on the edge of a chair, place one arm at the side, straighten your back, and raise your other arm above your head with your palm facing inward, leaning to the opposite side. Or stretch your arms back, hold the outer edge of the chair back, and push your chest forward.

Image source: Galaxy

4. Neck and shoulder stretching

Most office workers suffer from "mouse hand", which is a type of disease caused by hand and wrist strain such as carpal tunnel syndrome and tenosynovitis. The main symptoms are numbness, pain, stiffness and weakness in the front of the wrist. This action can effectively stretch the forearm and elbow muscles and reduce muscle stiffness.

Wrist: Extend your right arm with your palm facing up and use your left hand to gently pull your fingers down and back. Switch hands and repeat.

Shoulders: Straighten your arms, interlace your fingers, turn your palms outward, and gently raise your arms overhead, stretching your body.

Image source: Galaxy

5. Half Downward Dog Pose <br /> This well-known yoga pose is a versatile full-body stretch that is particularly good for stretching the leg muscles. Stand facing the back of a chair, place your hands on the back of the chair, step your feet back as far as possible, and press your back down while keeping your arms and legs straight.

Image source: Galaxy

2

Correcting sitting posture

If you must sit, then posture is very important. The best sitting posture is actually the one that best adapts to the natural structure of the human body, not the most comfortable one. Only by conforming to the natural structure of the human body, the muscles and bones are less stressed, soreness and injury are less likely to occur, and the arms can be flexible when working.

How to master the best sitting posture for workers? We have summarized the following 5 key points:

1. Keep your feet flat

Adjust the seat height to ensure that the entire sole of the foot is flat on the ground. If the seat is too high, the feet will be suspended in the air or on tiptoe, so you need to lower the height or put a pedal under your feet. If the seat is too low, you will bend your knees and hook your feet after sitting down, which will also increase the pressure on the patellar joint.

Feet flat, Image source: Galaxy

2. Even distribution of power

The angle between the thigh and the calf is more comfortable at 95°~100°. At this time, the thigh and buttocks evenly bear the body weight, so no part of the body will be pressed uncomfortably. At the same time, the pressure on the patellar joint is also small, which will not cause problems such as anterior knee pain.

3. Maintain the curvature of the spine

When standing naturally, the spine is not a straight line, but has four physiological curvatures, and the four physiological curvatures are all linked. After sitting down, it is most comfortable to basically maintain this curvature.

Assuming that the pressure on the waist is 100% when standing in the correct neutral position, when the back and knees are at a 90-degree angle, the pressure on the lumbar spine reaches 140%, which is greater than the pressure in the slightly backward posture. And the forward leaning is the most stressful of these postures. Therefore, considering the neutral curvature of the body and the pressure on various parts of the body, the best sitting posture should be to lean back slightly.

Schematic diagram of different sitting angles and lumbar spine stress, image source: boostphysio

In addition, the bending direction of the cervical spine should be consistent with that of the lumbar spine. If you lower your head too much, the cervical spine will bend in the opposite direction, which can easily cause headaches and shoulder and neck pain. In addition, the weight of the head is equivalent to one-seventh of the body weight, and stretching the head forward will increase the pressure on the neck by 3 to 5 times.

Schematic diagram of sitting posture and lumbar spine stress.

Schematic diagram of the angle of bowing and the pressure on the spine. Image source: boostphysio

The thoracic spine is in a mild kyphosis in its natural state, and the thoracic spine is relatively less mobile. A hunchback and a completely straightened thoracic spine will work together to straighten or bend the curvature of the cervical and lumbar spine. Therefore, it is best to maintain a normal mild kyphosis state of the thoracic spine.

In general: raise the monitor appropriately and let your eyes look directly at the upper edge of the monitor. Generally, the curvature of the spine will be in a naturally stretched state at this time.

4. Support with your elbows

To reduce shoulder and neck pain, in addition to maintaining normal spinal curvature, you should also avoid shrugging your shoulders and hanging your arms. Supporting your elbows and forearms on a table or armrest can help relax your shoulders. When typing, keep the angle between your upper arm and forearm at about 100 degrees to reduce the pressure on your shoulders and neck.

5. Be symmetrical

The posture of "Ge You lying" or leaning on the armrest makes the left and right limbs in an inconsistent posture, and the force on the muscles and bones is uneven. Over time, the spinal stabilizing muscles may be strained, or even postural scoliosis may occur. Therefore, it is not advisable to lean on the chair when sitting for a long time. The spine should be kept neutral and the shoulders at the same height.

It should be reminded that when we sit, it is against human nature to maintain a standard angle for a long time. The better posture should always be dynamic, not static. Please keep the correct posture in mind and remind yourself from time to time, but don't make yourself "obsessive-compulsive".

Workers marked their sitting postures, image source: Xinghe

3

Choosing the right equipment for your office environment

In addition to knowing what kind of sitting posture is the healthiest, it is also important to create a good sitting environment.

Work desk and chair

When sitting for a long time, try to choose a chair with a backrest , which can reduce 60% of the pressure on the spine and relax the muscles. If you sit for a short time, you can choose a stool without a backrest, which can maintain body balance by muscle contraction and also play a role in exercise.

Also, make sure the computer is at an appropriate height and the chair is made of a material that is neither too soft nor too hard. Among the different types of backrests, the ones that fit the natural curvature of the spine are the most comfortable. If the chair back is very straight, you can add a thin pad behind your waist to support your lumbar region. When there is no desk to support your arms, the armrests of the chair can help bear the weight and reduce the pressure on your shoulders and neck.

Monitor and keyboard

When working with a laptop or tablet, you often hunch your back to see the monitor clearly. Use a stand to raise the computer, keep your line of sight roughly parallel to the top edge of the monitor, and make sure the monitor is an arm's length away from you, which makes it easier to maintain a good sitting posture.

However, raising the computer will also raise the keyboard, which will increase the pressure on the wrist when typing. Therefore, it is best to connect an external keyboard to the desktop (preferably with a wrist rest), or place the computer flat on the desktop and connect it to a higher monitor.

Image source: Galaxy

Well, that’s all for this sharing. Have you learned it? Share it with your friends and let’s sit for a long time scientifically together!

References

[1] Cao Z, Xu C, Zhang P, Wang Y. Associations of sedentary time and physical activity with adverse health conditions: Outcome-wide analyzes using isotemporal substitution model. EClinicalMedicine. 2022;48:101424. Published 2022 Apr 28. doi:10.1016/j.eclinm.2022.101424

[2] Wilke H, Neef P, Hinz B, Seidel H, Claes L. Intradiscal pressure together with anthropometric data--a data set for the validation of models. Clin Biomech (Bristol, Avon). 2001;16 Suppl 1:S111-S126. doi:10.1016/s0268-0033(00)00103-0

[3] Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behavior. Br J Sports Med. 2020;54(24):1451-1462. doi:10.1136/bjsports-2020-102955

[4] Kandola A, Lewis G, Osborn DPJ, Stubbs B, Hayes JF. Depressive symptoms and objectively measured physical activity and sedentary behavior throughout adolescence: a prospective cohort study. Lancet Psychiatry. 2020;7(3):262-271. doi:10.1016/S2215-0366(20)30034-1

Planning and production

Author: Deng Ting, attending physician of orthopedics department of Changsha Third Hospital

Reviewer: Tang Qin, Director and Researcher of the Science Popularization Department of the Chinese Medical Association

Planning丨Lin Lin

Editors: Lin Lin, Jin Yufen (Intern)