Updated:
by
Demetrios J. Karamichos, MD, RVT, RPVI, DABVLM
Medically reviewed by Demetrios J. Karamichos, MD, RVT, RPVI, DABVLM
In February 2025, the San Antonio Spurs announced that Victor Wembanyama had deep vein thrombosis in his right shoulder. His season was over. Roughly a month later, the Milwaukee Bucks announced that Damian Lillard had deep vein thrombosis in his right calf and would be out indefinitely.
Two of the fittest athletes on the planet, sidelined by blood clots within weeks of each other. Then came the warning from someone who lost a career to clots.
Chris Bosh, whose blood clots forced him out of the NBA at age 32, told HoopsHype that he had another pulmonary embolism (PE) in January 2026 and nearly died. His advice to Wembanyama was blunt: “Take your medicine.” He warned that Wembanyama’s team has to keep him on his regimen, “because it only takes one more time.”
The blood clot experiences of these peak athletes are a cautionary tale for the rest of us. Fitness does not rule out blood clot risk. Travel days, training through an injury, and long sessions in the heat all raise clot risk, and the earliest signs look a lot like ordinary soreness.
Blood clots are common. The Centers for Disease Control and Prevention (CDC) estimates that as many as 900,000 people in the United States are affected by venous thromboembolism each year, and that 60,000 to 100,000 Americans die from it. In about one quarter of pulmonary embolism (PE) cases, sudden death is the first sign that anything was wrong.
Athletes are not exempt from experiencing a dangerous clot. In a 2017 review of publicly reported injury records, researchers identified 55 blood clot events across the NHL, MLB, NFL, and NBA between 1999 and 2016. Players averaged 6.7 months away from competition, and about 85 percent eventually returned to play.
Here is the nuance that most sports coverage overlooks. Athletes carry fewer of the classic clot risk factors than the general population. They tend to be younger, leaner, and more active. What sport adds is a different set of risks tied to training, travel, and injury. Height is a separate factor that matters in sports like basketball and volleyball.
A Swedish study of more than 2.7 million people published in the American Heart Association Journal Circulation: Cardiovascular Genetics found that height is an independent predictor of clot risk, with risk lowest among the shortest men and women.
Here is why that matters to you. Nothing about you looks like a blood clot risk. You train, you eat well, your resting heart rate is low. So when your calf tightens up, you will assume you overdid it, and so will your coach and your training partners. That assumption is what costs people vital time in getting a clot checked.
Athletes tend to wait. You assume you tweaked something, so you ice it and take a few days off. If the swelling is on one side and it is not going away, testing beats waiting. Center for Vein Restoration offers DVT rule-out appointments the same day or the next day. Call 877-SCAN-DVT (877-722-6388) to schedule DVT rule-out testing.
A clot becomes more likely when blood slows down, when a vein wall is injured, or when blood becomes stickier than normal. Athletic life can produce all three conditions.
Long-distance travel. Competing often means flying. Sitting still for hours slows blood flow in the leg veins. A 2024 review of thrombotic risk in athletes lists frequent long-distance flights among the sport-related conditions that increase clotting risk.
Injury and immobilization. A sprain, a fracture, or post-surgical rest can keep a leg immobilized for days or weeks. The same review identifies immobilization following sports injuries as a recognized risk factor. Trauma can also directly damage the vein wall.
Dehydration and hemoconcentration. Intense training and hot conditions draw fluid from the body. Blood volume drops, and the blood becomes more concentrated. A 2024 review indexed in PubMed Central lists exertion-induced hemoconcentration and dehydration among the acquired conditions that raise clot risk in athletes.
Repetitive overhead motion. Swimming, pitching, weightlifting, and wrestling put sustained strain on the veins that run under the collarbone. More on this below, because it is the risk athletes most often overlook.
Personal risk factors that travel with you. An inherited clotting disorder, a family history of clots, a previous clot, oral contraceptive use, and pregnancy or recent childbirth all raise risk regardless of fitness level. Serena Williams, who has lived with a clotting history since 2011, developed a pulmonary embolism after the birth of her daughter in 2017. Fitness did not remove that risk.
Most people picture a blood clot as a leg problem. In competitive athletes, that assumption is wrong often enough to be dangerous.
In that 2017 review of the four major North American leagues, upper extremity clots were the single most common presentation. Researchers counted 19 upper extremity DVTs, compared with 15 in the lower extremity. Wembanyama's clot was in his shoulder, not his leg.
There is a name for the version that shows up in athletes. Paget-Schroetter syndrome, also called effort thrombosis, is a clot in the axillary or subclavian vein. The National Institutes of Health StatPearls entry describes it as effort-induced thrombosis that typically appears in young, healthy people after repetitive upper extremity exertion. It is uncommon, at roughly 2 cases per 100,000 people per year in the United States, but between 60 and 80 percent of people with an upper extremity DVT report repetitive, vigorous overhead activity around the time symptoms began.
Warning signs in the arm look different from the leg. Watch for sudden swelling of the whole arm, a heavy or aching feeling, a bluish or reddish color change, and visible veins standing out across the shoulder or chest.
Center for Vein Restoration treats vein disease and blood clots of the legs. We do not evaluate or treat clots of the arm, shoulder, or chest, including Paget-Schroetter syndrome.
If you have the arm or shoulder symptoms described above, do not wait for a vein clinic appointment. Contact your primary care physician immediately or go to the nearest emergency department. Upper extremity clots need urgent evaluation by a vascular specialist or emergency physician.
Wherever a deep vein clot forms, the threat is the same: a piece can break loose and travel to the lungs. That is a pulmonary embolism, and it is a medical emergency.
The same 2017 review found six athletes who had both a DVT and a pulmonary embolism, and 15 who had a pulmonary embolism on its own. Upper extremity clots are not a lesser category. Left undiagnosed or untreated, they can travel to the lungs just as leg clots do. Bosh's first clot began in a leg and reached a lung.
That is the through line connecting Bosh, Wembanyama, Lillard, and Williams. Different veins, different sports, different decades. In every case, the danger was the same: a clot that reaches the lungs.
Athletes are conditioned to work through soreness. That instinct is exactly what makes a clot easy to miss. Let's compare common training soreness with signs of a blood clot:
If you cannot confidently tell the difference in yourself, that is the point. Neither can most athletes. Swelling in one limb that does not resolve is not a normal training response. Get it checked.
📞Call CVR at 877-SCAN-DVT (877-722-6388) to schedule DVT rule-out testing.
You cannot eliminate the possibility of a blood clot, but you can reduce your risk and shorten the time to diagnosis if one develops.
Center for Vein Restoration is the nation's largest physician-led vein center, with more than 130 locations across 23 states. Our board-certified physicians evaluate and treat leg vein conditions, including varicose veins, chronic venous insufficiency, and deep vein thrombosis.
Q: Can you get a blood clot from working out?
A: Exercise itself does not cause blood clots, and regular activity is good for circulation. What raises risk is the surrounding context: the flight to the meet, the cast after an injury, dehydration in the third hour of a race, or repetitive overhead motion that irritates a vein under the collarbone.
Q: Are athletes more likely to get blood clots than other people?
A: Not in a simple sense. Athletes generally have fewer of the classic risk factors, such as older age and inactivity. But they face specific sport-related risks, and clots do occur in this group. The more useful takeaway is that being fit does not rule out a clot.
Q: What does a blood clot feel like in the leg?
A: Common signs include swelling in one leg, a deep cramping or aching pain that does not ease with rest, warmth, and redness or discoloration. Many people mistake it for a pulled calf muscle.
Q: Can you keep playing sports after a blood clot?
A: Many athletes return. In the 2017 professional-league review, roughly 85 percent returned to play. Blood-thinning medication raises bleeding risk, so contact sports require careful, individualized decisions made with your treating physician.
Q: When should I go to the emergency room?
A: Call 911 for sudden shortness of breath, sharp chest pain that worsens when you breathe in, a racing heartbeat, fainting or near-fainting, or coughing up blood. These can signal a pulmonary embolism.
Q: Does Center for Vein Restoration treat arm and shoulder blood clots?
A: No. CVR treats leg vein conditions. Your primary care physician, a vascular specialist, or an emergency department should evaluate arm, shoulder, and chest clots.
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