Prolonged Sitting: What Risks It Hides and How to Prevent Them, Explained by an Orthopaedic Doctor

What matters most for your health is not necessarily the total number of hours spent sitting, but how often you take breaks. According to Dr Ioan Stan, an orthopaedic surgeon and traumatologist specialising in ankle and foot pathology, six consecutive hours of sitting without movement can be more harmful than a full working day in which sitting is regularly interrupted by a few minutes of movement, as he explained to Digi24.ro.

The consequences go beyond back pain. A lack of breaks affects leg muscles, blood circulation, nerves, and metabolism.

Which areas of the body are affected

During prolonged sitting, the activity of the quadriceps, gluteal muscles, and calves decreases, whilst the hip flexors — particularly the iliopsoas and rectus femoris — remain in a shortened position for extended periods. This muscular imbalance can alter body posture and contribute to lower back pain, the doctor explains.

Blood circulation also suffers: when we remain motionless for long periods, calf muscle contractions decrease, and the "muscle pump" that helps blood flow back to the heart becomes less efficient. The result can be a sensation of heavy legs, muscle fatigue, and swollen feet — symptoms that tend to worsen towards the end of the day.

Extended periods of immobility — such as during flights or long car journeys — can increase the risk of deep vein thrombosis, particularly in people who have additional risk factors. This occurs when a blood clot forms in a deep vein, most commonly in the calf, and manifests as pain, tenderness, or swelling in the leg. If the clot breaks free and travels to the lungs, it can cause a pulmonary embolism — a serious complication requiring emergency medical attention.

A sedentary lifestyle also affects metabolism: muscles that are insufficiently active absorb less glucose and burn less energy, which can contribute over time to changes in blood sugar levels and blood lipid levels, even in people of a healthy weight.

The spine, nerves, and feet also feel the effects

Prolonged sitting, especially in an incorrect position, places additional pressure on the lumbar region and the cervical spine. Intervertebral discs have no direct blood supply, and the exchange of nutrients occurs through diffusion — a process sustained by alternating between movement and rest.

In the cervical region, projecting the head forwards increases the mechanical load on the neck. Shortening of certain muscles around the hips can alter pelvic position and accentuate lumbar lordosis, contributing to back pain.

Pressure in the gluteal area can irritate the sciatic nerve, whilst keeping the legs crossed can affect the peroneal nerve near the knee — situations that may cause tingling or numbness, usually temporary and resolving once the position is changed.

Prolonged immobility can also contribute to shortening of the Achilles tendon and tightening of the plantar fascia, causing pain in the sole or heel — sometimes felt more acutely with the first steps in the morning.

Common symptoms and warning signs

Common symptoms include pain or a sensation of joint stiffness when standing up (which eases after the first few steps), lower back pain in the evening, a feeling of heaviness and fatigue in the legs, swelling of the feet, numbness and tingling radiating from the thigh down to the foot, morning sole pain, and muscle spasms — including in the neck and shoulder blade area.

However, certain signs require medical assessment: persistent pain that does not ease readily or wakes the person from sleep, tingling and numbness below the knee, a sensation of muscular weakness, and the sudden appearance of a swollen, red, and painful calf — a situation that may raise suspicion of thrombosis and must be investigated urgently. Additionally, any pain or discomfort that persists for four to six weeks despite measures taken should be assessed by a doctor.

How to prevent the effects of prolonged sitting

For those who spend seven to eight hours a day at a desk, the regularity of breaks matters more than the intensity of physical effort. The doctor recommends interrupting sitting every 30 to 45 minutes for a few minutes of movement — a short walk around the room, a trip to the bathroom, or simply changing position are sufficient.

Those who would like specific exercises can try lunges held for around 30 seconds, between 5 and 20 calf raises, and calf and Achilles tendon stretches against a wall. When standing up from a chair is not possible (for example during a meeting), approximately 20 ankle flexions and extensions can be performed to activate the muscle pump and stimulate blood circulation.

For the cervical region, around 10 chin-to-chest movements are recommended. The gluteal muscles can be activated through 5-second contractions in a set of approximately 10, to which shoulder rotations and drawing the shoulder blades towards the spine can be added.

Hydration and sleep also contribute to the body's recovery. The doctor recommends avoiding wearing heels throughout the entire day and choosing comfortable footwear where possible.

Correct posture at a desk reduces pressure on the spine and cervical region: feet should rest flat on the floor, hips positioned slightly higher than the knees, and the back should not slouch on the chair or lean forwards — ideally supported by a lumbar support. The monitor should be positioned at eye level so the neck is not permanently tilted, and the back should form an angle of approximately 90 degrees to the thighs. It is also advisable to avoid crossing one leg over the other for prolonged periods, as this affects posture and the distribution of body weight, concluded Dr Ioan Stan.