“Sit up straight” is something many people heard all through their school years, every time Mom walked past the study desk. Once you start working, it turns into a reminder you give yourself. At nine in the morning your back is still straight, by three in the afternoon you have slowly slid down the chair, and in the evening you feel you have let your spine down.
In 2019, an American physical therapy journal published a viewpoint article that took exactly that phrase as its title, with a second half: time to re-evaluate. Slater et al. wrote that the belief that spinal pain comes from sitting, standing or bending with the wrong posture does not have strong evidence behind it, even though a whole posture-correction industry has grown up around that belief.
Does bad sitting posture cause back pain?
There is so much research on this that people have had to write reviews of reviews. Swain et al. (2019) pooled 41 systematic reviews on posture, prolonged sitting, prolonged standing and low back pain. Some reviews found a link, some did not. So far there is no consensus that posture causes low back pain; the two do go together, but a cause-and-effect relationship has not been proven. How prolonged sitting contributes to back pain is discussed in our article an overview of back pain.
Even a textbook posture gets tiring if you hold it long
However balanced a posture is, it keeps the same muscle groups working nonstop. Sit bolt upright like the model on a poster, and the muscles along both sides of the spine and the back of the neck have to stay tensed the whole time; by mid-morning or mid-afternoon the muscles tire, and the body looks for another position on its own to share the work with other muscle groups. Sliding your hips forward or propping up your chin in the late afternoon is mostly the body’s way of asking for a rest. An easier approach to follow is to sit however feels comfortable, then change position before the muscles have time to tire.
People who sit lopsided usually have a reason
Someone who is reminded again and again but still leans to one side is usually compensating for something. The most common reasons are:
- A tilted pelvis or legs of different lengths, so the body shifts its weight onto one buttock on its own;
- Poor eyesight or glasses with an outdated prescription, so the head has to push forward to read clearly, and the neck and upper back tense along with it;
- Weak abdominal and buttock muscles that cannot support the pelvis for long, so the body slowly slides down the chair and the back rounds.
A small misalignment in the pelvis can set off a chain of compensations all the way up to the neck, as our article on musculoskeletal pain explains. Simply telling someone to sit up straight while ignoring those reasons means they can hold it for a while, and then everything goes back to how it was.
Sitting cross-legged on a floor mat for a meal, or on a low plastic stool at a sidewalk café, is fine if it is only for a while. Sitting with your legs crossed under the desk for hours is different: the peroneal nerve on the outer side of the knee can get compressed, causing numbness on the top of the foot; read more in our article on peroneal nerve compression.
How much does getting up during the day help?
Getting up to pour a glass of water is also a change of position. The Cochrane review by Shrestha et al. (2018), covering 34 studies with 3,397 people, found that sit-stand desks reduced sitting time by about 100 minutes per workday in the first three months, and by about 57 minutes when followed for three to twelve months. In one study, short breaks of 1–2 minutes after every half hour cut 40 minutes of sitting a day compared with two long 15-minute breaks. The quality of the evidence was rated low to very low.
Whether sitting less also means less pain is still unclear. Another Cochrane review, in 955 people who sit a lot at work and already had musculoskeletal symptoms, did not find that sit-stand desks or activity trackers meaningfully reduced back, neck or shoulder pain (Parry et al., 2019). The evidence here is also low. Getting up during the day is still worth doing; if you already have pain, you also need to find out why you sit lopsided.
When tired eyes, neck pain, bloating and poor sleep come together
In office workers, the eyes often get tired from mid-afternoon, the neck and shoulders stiffen, the hands sometimes go numb, the stomach feels bloated after a lunch eaten in a hurry at the desk, and at night sleep is slow to come. These often go together because they share one foundation: sitting still for too long and long-term stress. The Su Wen (素问 / 素問, Plain Questions) records that prolonged sitting harms the flesh (“prolonged sitting injures the flesh”, 久坐伤肉 / 久坐傷肉, jiǔ zuò shāng ròu). In traditional medicine, the Spleen both governs the flesh and muscles (脾主肌肉, pí zhǔ jī ròu) and takes care of digestion, so people who sit a lot and think a lot often have both tired muscles and bloating.
The doctors at Tam Duc look at that shared foundation through the health triangle, looking for the heaviest of its three sides: Structure, Chemistry and Mind. How screens tire the eyes and then lead to back pain is covered in a separate article on eye strain, and if your hands often go numb at night, read our article on carpal tunnel.
Tiredness from sitting, or a sign of another illness
Tiredness from sitting usually eases when you get up and walk around, or after a night’s sleep. Numbness or weakness in the arms or legs that gets worse week by week, clumsy hands (buttoning a shirt or holding chopsticks is harder than before), or an unsteady walk are signs that need an early neurological examination; don’t blame the chair. Back pain with fever, numbness in the saddle area or being unable to pass urine means seeing a doctor right away; the full list is in our article an overview of back pain.
What the doctor looks at when you sit down
When you see Dr. Dinh Ngoc Duc (MD, MSc in Traditional Medicine) for tiredness from sitting, you will be asked how many hours a day you sit and which area tires first. The doctor asks you to sit the way you do at work, to see which way your shoulders, pelvis and head lean, measures the length of both legs, and then uses muscle testing to find out whether the abdominal and buttock muscles can hold the pelvis steady.
When muscle testing shows the pelvic area is not working properly, the doctor may place wedge blocks under your pelvis while you lie down, or mobilize the pelvis and sacrum, then have you stand up and take a few steps to see whether the buttock and abdominal muscles are holding the pelvis better. For a neck and shoulders that have been stiff for many months, the doctor uses acupuncture around the neck, shoulders and upper back; for people whose tiredness comes with bloating and a poor appetite, the Spleen deficiency type (脾虚 / 脾虛, pí xū), the doctor modifies an herbal decoction toward strengthening the Spleen. Exercises for home target the abdominal and buttock muscles and can be done right beside your desk.
Worth keeping
- Set a reminder, and about every half hour get up and walk around for a minute or two;
- Each time you sit back down, choose a different position from the last one;
- Adjust your chair so both feet rest flat on the floor, and if you are short, add a footrest;
- If you sit cross-legged or with your legs crossed, switch which leg is on top;
- If you still lean to one side despite paying attention, see a doctor to find the reason.
References
- Slater D, Korakakis V, O’Sullivan P, Nolan D, O’Sullivan K (2019). “Sit Up Straight”: Time to Re-evaluate. J Orthop Sports Phys Ther 49(8):562-564. https://doi.org/10.2519/jospt.2019.0610
- Swain CTV, Pan F, Owen PJ, Schmidt H, Belavy DL (2019). No consensus on causality of spine postures or physical exposure and low back pain: A systematic review of systematic reviews. J Biomech 102:109312. https://doi.org/10.1016/j.jbiomech.2019.08.006
- Shrestha N, Kukkonen-Harjula KT, Verbeek JH, Ijaz S, Hermans V, Pedisic Z (2018). Workplace interventions for reducing sitting at work. Cochrane Database Syst Rev 12(12):CD010912. https://doi.org/10.1002/14651858.CD010912.pub5
- Parry SP, Coenen P, Shrestha N, O’Sullivan PB, Maher CG, Straker LM (2019). Workplace interventions for increasing standing or walking for decreasing musculoskeletal symptoms in sedentary workers. Cochrane Database Syst Rev 2019(11):CD012487. https://doi.org/10.1002/14651858.CD012487.pub2
