Sitting for a long time is harmful to the body, and I believe everyone has heard it to a greater or lesser extent. But how long is it considered to be sedentary? I'm sure many people can't say.
Let's start with the answer: It's not that sitting for 8 hours is called a long time, but sitting for more than 90 minutes can be considered sedentary behavior. In other words, the time spent sitting or lying down playing two games or watching a movie is already considered sedentary.
However, for the poor migrant workers, they spend a whole day moving bricks in front of the computer on weekdays, and they just want to be paralyzed after work, and they don't want to move at all. After all, I can't finish the work and press my butt on the office chair for 8 hours, after all, I just want to let my spirit and muscles "lie flat" when I finally get off work, and sitting for a long time is really "forced by life".
How can we stay as healthy as possible while not sitting for a long time? Today, I invite an orthopedic surgeon to talk in detail.
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How to resolve the dangers of sedentary care?
Pay attention to these 3 points
Studies have found that sitting for more than 6 hours a day increases the risk of a variety of diseases, including cancer, cardiovascular disease (including coronary heart disease and stroke-related), diabetes, kidney disease, suicide, chronic obstructive pulmonary disease, pneumonia (due to solids and liquids), liver and other digestive disorders, Parkinson's disease, Alzheimer's, neurological disorders, and musculoskeletal disorders.
"Sedentary" has been listed as one of the top ten fatal and pathogenic killers, and its damage to the body does not need to be described too much, after all, most of the workers are forced to "sit for a long time" by life, so is there any way to resolve the harm of sedentary life?
1. Correct sedentary behavior
It's a good idea to leave your seat every 30 minutes, even if it's to get up and pour a glass of water, walk around the office, or get up to work for a while before sitting down.
If possible, it would be nice to be able to do some stretching exercises that allow for office conditions. Today, I recommend a few simple stretching movements that can be done on an office chair. They have a small range of movement, do not interfere with other people's work, and although the amount of activity is small, it must be much better than not moving at all.
1. Hip stretching
The hips and lower back of the worker will become tense due to sitting for a long time, and this seated stretch can stretch the hip and lower back at the same time.
Sit on the edge of the chair with your feet hip-width apart, cross your ankles on the opposite knee, and press your back forward and down until your chest and abdomen are close to your calves and knees.
Image source: Galaxy
2. Lower back pine solution
Rotate the chair to the side, hold the back of the chair with the arm closest to the back of the chair, and gently twist the front of the body towards the back of the chair. Extend your other arm toward the opposite knee, as far as you can.
Image source: Galaxy
3. Open shoulder training
This stretches the shoulders and opens the ribcage of the chest, allowing more fresh air to enter the lungs and increasing oxygen uptake in organs throughout the body.
Sit up straight on the edge of the chair, put one arm to the side, straighten your back, and raise the palm of the other arm inward above your head, leaning to the opposite side. Or stretch your arms back, grasp the outside edge of the seat back, and push your chest forward.
Image source: Galaxy
4. Neck and shoulder stretching
Most office workers suffer from "mouse hand", a type of disease caused by hand and wrist strain such as carpal tunnel syndrome and tenosynovitis. The main manifestations are numbness, pain, and stiffness in the front of the wrist. This movement can effectively stretch the forearm and elbow muscles and reduce muscle stiffness.
Wrist: Extend your right arm with palm up, gently pull your fingers down and back with your left hand, switch hands, and repeat.
Shoulders: Stretch your body by straightening your arms with your fingers crossed and palms turned outward, gently raising your arms above your head.
Image source: Galaxy
5. Semi-lower dog type
This well-known yoga asana is an all-purpose full-body stretch that is especially good for stretching the leg muscles. Stand facing the back of the chair with your hands on the back of the chair and your feet back as far back as you can, pressing your back down while keeping your arms and legs straight.
Image source: Galaxy
2. Correct sedentary posture
If you must sit, then posture is important. The best sitting posture is actually the sitting posture that is most adapted to the natural structure of the human body, but it is not how comfortable it is. Only by conforming to the natural structure of the human body and having less pressure on the muscles and bones can it not be prone to soreness and injury, and can also ensure that the arm can move flexibly during work.
How to master the best sitting posture for migrant workers? We have summarized the following 5 key points:
1. Flatten your feet
Adjust the height of the seat so that the ball of your foot is flat on the ground. When the seat is too high, your feet will hang in the air or stand on your tiptoes, so you need to lower the height or put pedals under your feet. If the seat is too low, it will bend the knees and hook the feet after sitting, which will also increase the pressure on the patellar joint.
Feet flat, image source: Galaxy
2. Power Equalization
The angle between the thighs and calves is 95°~100°. At this time, the thighs and buttocks bear the weight of the body evenly, so that a certain section will not be pressed uncomfortably, and the pressure on the patellar joint is also small, which will not cause problems such as anterior knee pain.
3. The curvature of the spine should be maintained
When standing naturally, the spine is not a straight line, but has four physiological curvatures, and all four physiological curvatures are linked. After sitting down, it is most comfortable to maintain this level of flexion.
Assuming 100% lumbar pressure when standing in a correct neutral position, the lumbar spine will be 140% stressed when sitting with the back and knees at a 90-degree angle, which is more stressful than a slightly backward position. Leaning forward is the most stressful of these postures. Therefore, taking into account the curvature of the body's neutral position and the pressure on all parts of the body, the best sitting posture should be to lean back slightly.
Schematic diagram of sitting posture and lumbar spine force at various angles, image source: Boostphysio
In addition, the direction of curvature of the cervical spine should be consistent with that of the lumbar spine. If the head is lowered excessively, the cervical spine will bend in the opposite direction, and headaches and shoulder and neck pain will easily occur. Moreover, 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 3~5 times.
Schematic diagram of sitting posture and lumbar spine force.
Schematic diagram of the angle of the head bowed versus the pressure on the spine, image credit: Boostphysio
The thoracic vertebrae are mild kyphosis in their natural state, and the thoracic spine is relatively less active, and the hunched back and the fully straightened thoracic vertebrae will work together to straighten or bend the curvature of the cervical and lumbar vertebrae, so it is best to maintain the normal mild kyphosis of the thoracic vertebrae.
In general: Raise the monitor appropriately so that your eyes look directly at the upper edge of the monitor, and the curvature of the spine will generally be in a natural stretch at this time.
4. Elbow support
To reduce neck and shoulder pain, in addition to maintaining normal spinal curvature, avoid shrugging shoulders and hanging arms. Bracing your elbows and forearms on a table or armrest can help your shoulders relax. When typing, keep the angle between your upper arm and forearm at about 100° to put less pressure on your shoulder and neck.
5. The left and right sides should be symmetrical
The posture of "lying down" or reclining on the armrests makes the posture of the left and right limbs of the body inconsistent, and the musculoskeletal force is uneven, and for a long time, there may be strain of the stabilizing muscles of the spine, and even postural scoliosis. Therefore, it is not advisable to recline in a chair when sitting for a long time, and the spine should be neutral and the shoulders should be at the same height.
It is important to note that it is anti-human to maintain a standard angle for long periods of time when we are sitting, and that a better posture should always be dynamic, not static. Keep the correct posture in mind and remind yourself of it, but don't make yourself "obsessive-compulsive" too.
Migrant workers mark sitting posture, image source: Galaxy
3. Choose the right equipment for the office environment
In addition to having a good idea of what kind of sitting posture is the healthiest, it is also important to create a good sedentary environment.
Work desks and chairs
When sitting for long periods of time, try to choose a chair with a backrest, which can reduce the pressure on the spine by 60% and relax the muscles. If you sit for a short time, you can choose a stool without a backrest, and use muscle contractions to maintain your balance, and it can also play a role in exercising.
Also, make sure that the height of the computer is appropriate and that the material of the chair is not too soft or too hard. Among the different types of backrests, the one that fits the natural curvature of the spine is the most comfortable. If the back of the chair is straight, a thin cushion can be added behind the waist to support the lumbosacral region. When you don't have a table to support your arms, the armrests of your chair can help carry weight and reduce pressure on your shoulders and neck.
Monitor & Keyboard
When working on a laptop or tablet, it's common to hunch over your head to see the monitor. It's easier to sit in a good sitting position by raising your computer with a stand that keeps your eyes almost parallel to the upper edge of the monitor, and keeping the monitor arm's length away from you.
However, raising the computer will also raise the keyboard, increasing the pressure on your wrist while typing. Therefore, it is best to connect an external keyboard to the desktop (preferably with a wrist rest), or to connect a computer with a higher monitor with the desktop flat.
Image source: Galaxy
Okay, the above is the sharing of this time, have you learned? Forward it to your friends and sit together scientifically!
bibliography
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[3] Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. 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 behaviour 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丨Deng Ting, Attending Physician of the Department of Orthopedics, Changsha Third Hospital
Review丨Tang Qin, Director of the Science Popularization Department of the Chinese Medical Association, Researcher
Planning丨Lin Lin
Editor丨Lin Lin, Jin Yufen (intern)