Experts warn prolonged sitting and crossing legs at work may raise risk of deadly blood clots

A health industry specialist has warned that prolonged sitting in the workplace — particularly with legs crossed — may increase the risk of life-threatening blood clots, a danger long associated with long-haul air travel.

Tristan Hulbert, managing director of medical equipment provider Vivid Care, told the Daily Mail that sitting with the legs crossed can compress veins in the lower limbs, slowing circulation and creating pressure points that may raise the chance of clot formation. He used the term "e-thrombosis," coined in 2003, to describe venous blood clots linked to extended periods at computers, desks or in gaming chairs.

Medical authorities have long recognised that prolonged immobility is a risk factor for venous thromboembolism (VTE), the umbrella term for deep vein thrombosis (DVT) and pulmonary embolism (PE). Clinicians warn that clots that form in deep veins, typically in the legs, can travel to the lungs and cause a potentially fatal pulmonary embolism if not detected and treated.

Researchers and clinicians identify several established risk factors for VTE, including advanced age, recent surgery, active cancer, smoking, obesity, hormonal therapies and inherited clotting disorders. Extended periods of sitting without changing position are also a recognised contributing factor because they reduce blood flow in the calves and lower legs.

Hulbert said many office workers sit for eight or more hours a day without moving, and that routinely crossing the legs may exacerbate circulatory restriction. "When you cross your legs while sitting, you create pressure points that can significantly restrict circulation," he said. "The veins in your legs get compressed, which slows blood flow and increases the chance of clot formation."

Health professionals advise that simple workplace changes can reduce risk. Regular movement, such as standing or walking briefly every hour, stretching the calves, performing ankle pumps and avoiding prolonged periods with legs crossed can help maintain circulation. Employers and workers can also consider ergonomic seating and arranging tasks to encourage periodic standing.

People who are at higher baseline risk of VTE may be advised by clinicians to take additional precautions. These can include using graduated compression stockings during periods of prolonged immobility or following a clinician's guidance on medication for high-risk situations. Anyone concerned about their risk should consult a healthcare professional for individual assessment.

Symptoms that warrant prompt medical attention include swelling, pain or tenderness in one leg, warmth and redness over a vein, sudden shortness of breath, chest pain that worsens with breathing, or a rapid heartbeat. Those signs can indicate DVT or a pulmonary embolism and require urgent evaluation.

Public health messages and clinical guidance have emphasised awareness of VTE risks during widely known immobility scenarios such as long-haul flights. Hulbert and other commentators say similar vigilance is needed for routine office and home computer use, where hours of uninterrupted sitting are increasingly common.

While the degree of risk associated with leg crossing alone has not been quantified in large-scale prospective studies, clinicians stress that reducing prolonged immobility is a practical and low-risk measure. Regular movement and awareness of symptoms are consistent components of medical advice to limit the chances that a clot will form and progress to a serious complication.

Workers with concerns about VTE risk or existing medical conditions that predispose them to clotting should seek personalised medical guidance from a physician or specialist. Employers can support prevention by encouraging breaks, promoting workplace movement and considering ergonomic interventions that reduce the likelihood of prolonged constrictive postures.