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  • Writer's pictureGary Moller

How to Prevent Deep Vein Thrombosis (DVT) in Athletes and Traveling Sports Teams

(Updated, 22nd February, 2024)

Deep vein thrombosis (DVT, phlebitis) among apparently healthy men and women is disturbingly common. I will see as many as two cases per month.

Example: Former national class runner, now in early 60's, developed a calf strain after a short run.

This coincided with a journey by car to Auckland and back to Wellington.

He had booked in with me for some deep tissue massage of the injured calf.

He struggled into the office and had a pale complexion and a hint of purple on the lips. Since there was no history of an actual injury to the ankle I concentrated on assessing his pulses, blood pressure and circulation. On the basis of what I found, I referred him immediately to his doctor who immediately referred him to the hospital where it was confirmed he was suffering from blood clots in his leg.

To have massaged the leg, anything other than gently, may have dislodged a clot, which may have then found its way into the lungs - not good!

Cases encountered over just one Christmas period: Four males training as endurance athletes (running and cycling). They had come to see me for help with calf pain. Two required hospital specialist treatment. One developed a blood clot on his lung. A fourth person was sent off to his doctor with a suspected silent heart attack.

Massage Therapists - take note!

If a person, including an athlete comes to you for a massage of a sore calf muscle, consider the possibility that the pain is due to a deep vein thrombosis. You may be the first health professional that a person with DVT related pain seeks out for relief. Be vigilant! Massaging a limb with a silent DVT may prove fatal. Be aware of the signs and symptoms and do not hesitate to get medical help if a DVT is even remotely suspected.

Few people realise that athletes and very active people are among the most at-risk of developing a blood clot

But why did I encounter so many cases around Christmas? Well: Its easy to see why - Over-training, exhaustion, the excess stress of last minute work pressures, standing about at end of year corporate functions, drinking alcohol and eating too much fatty finger food; and then there is the Xmas shopping, kids not at school and then to top it all off - the relations arrive!

How to prevent deep vein thrombosis in athletes and traveling sports teams

Did you know that the circulation through the lower legs is reduced by as much as 50% when standing and 70% when sitting?

This has serious implications for the traveler. Blood which has already given up much of its oxygen and is burdened with metabolic wastes is now pooling in the legs. When blood stagnates like this it steadily loses its freshness. This is not good for your health and general well-being.

An athlete preparing to produce a world-class performance needs healthy red blood cells for peak oxygen transport and it may take up to three weeks to fully replace any damaged ones. If such damage has been done to blood cells then this is a good explanation why many athlete are feeling "flat" for a few weeks after long haul travel and seldom produce personal bests in competition.

New Zealand athletes may be at greatest risk of under-performance and harm from DVT because we have to travel further than any other sporting nation for international competition.

Are athletes at greater risk?

  • Three Olympic athletes from the British team were treated for DVT in Australia 2000.

  • It's been claimed that people who are athletic account for ten times more victims than any other risk factor.

  • About 85 percent of air travel thrombosis victims are athletic, usually endurance-type athletes like marathoners. People with slower resting blood flow are at greater risk of stasis, stagnant blood subject to clotting. Also, they are more likely to have bruises and sore muscles that can trigger clotting. No other risk factor comes close to this. Age over 60 is supposed to be a risk factor, but these victims are younger, 82% of them under 60.

Possible explanations include:

  • Athletic people with a lower resting pulse could be at greater risk of stasis, stagnant blood subject to clotting. The lower the pulse, the higher the possibility of blood stagnating in the legs.

  • Some athletes cheat with "blood doping", using a hormone called EPO, to increase their red blood cell volume. This thicker, stickier blood is very prone to clotting (Blood clots in race horses was once a common cause of death - excessive use of EPO).

  • Athletes may have better-developed superficial veins carrying more blood, reducing the flow in deep veins while at rest.

  • Athletic people may be more likely to have bruises or sore muscles which could trigger clotting. Recent injury, even a bruise, is a well-established risk factor.

  • Adrenal fatigue is rampant in athletes. Adrenal fatigue causes low blood pressure, an excessively low pulse and consequent pooling of blood in the legs.

  • Adrenal stress also increases blood clotting rate and is associated with poor venous tone, causing pooling in the legs.

What is deep vein thrombosis?

Much has been said and written recently about the dangers of economy class syndrome, or deep vein thrombosis (DVT). DVT refers to the formation of blood clots in the large veins of the body – usually in the legs and groin and sometimes in the arms and shoulders. It is sometimes referred to as phlebitis and there can be serious complications if a blood clot were to break loose and lodge in the lungs. Up to 20% of the total population could be at increased risk of developing blood clots. It has been estimated that there could be as many as four or five DVT cases per long haul flight with up to 10% of passengers suffering symptomless DVT. While DVT has been popularly associated with the cramped conditions of economy class travel, nobody is immune.

About 85% of air travel thrombosis victims are athletic, usually endurance-type athletes

When sitting, especially with the knees crossed, or if the edge of the seat is digging into the back of the knees, the blood vessels to and from the legs may be kinked and compressed. Muscles act as accessory pumps to the heart, pumping blood back to the heart. With knees bent and without regular and steady contraction of the leg muscles, the blood flow through the legs is seriously reduced. The same processes occur with the lymphatic circulation which refreshes the clear fluid that bathes and nourishes the body’s cells. If the lymphatic fluid is not pumped out by muscular contractions it pools in the limbs like stagnant pond water. This may show as visible swelling of the lower legs or hands. This is a very unhealthy condition for anybody - especially if you already have circulation problems.

Whether it is in a cramped aircraft cabin, motor vehicle, or an office, DVT does not discriminate

Venous blood is already low in life-giving oxygen and contains toxic waste products from cellular metabolic activity and tissue damage. This burdened blood is normally whisked back to the lungs, liver and kidneys to be re-oxygenated and cleansed - it should not be stagnating in the lower legs. If it sits about too long it will eventually go off and finally form blood clots in the leg.

Athlete or not: Nobody wants a build-up of stagnant, stale blood and fluid at any time - especially when traveling to a foreign land. Whether it is through air travel, or sitting for several hours in a car - stagnated circulation – let alone DVT – is a real threat to health and vitality. An experienced traveler will tell you that the body and brain can remain tired and sluggish for as long as 36 hours after a long journey of any kind – especially if it includes changes in time zones. The legs feel heavy, achy and swollen, reactions slow, the head may ache and breathing is laboured during exercise. Stagnant blood and lymphatic fluid that accumulated in the legs during travel is now being flushed back into the system, causing a period of general systemic toxicity.


Deep vein thrombosis is a life-threatening condition. The following advice is for prevention - not for treatment. If a deep vein thrombosis is suspected, then the person affected must be transported immediately to a hospital or emergency clinic for assessment by a doctor - nothing less!

Signs of possible DVT (Present in less than 50% of cases, so always take care)

  • Swelling and/or discomfort in a limb, groin, shoulder or even low back

  • Cold and/or discoloured limb

  • Shortness of breath, unusual fatigue

  • Blue lips, ashen, signs of general distress

  • Racing pulse

  • Pain in the leg

  • Tenderness in the calf (this is one of the most important signs)

  • Leg tenderness

  • Swelling of the leg

  • Increased warmth of the leg

  • Redness in the leg

  • Bluish skin discoloration

  • Discomfort when the foot is pulled upward


  • Do not sit for longer than one hour without getting up, moving about and stretching for several minutes. If in an aircraft, this means walking up and down the isle every half hour and/or doing special exercises.

  • It is often very impractical and totally unsafe to get up and walk about a plane, so do so at every opportunity.

  • If traveling by car, stop every hour for a brisk five minute walk or slow jog and don’t forget to stretch.

  • When sitting, avoid crossing the legs. If you can – keep your feet up with knees extended. Regularly flex and extend the ankles to pump the calf muscles.

  • Do not wear tight shoes or restrictive clothing, especially socks with elasticised cuffs that may cut circulation of the lower legs or feet.

  • Special compression stockings do reduce venous and lymphatic pooling in the legs and the subsequent risk of DVT. While there is no research that I am aware of to prove their worth, athletes may also benefit from wearing body-hugging athletic tights that include instep stirrups, rather than elastic ankle bands.

  • With dehydration, the blood becomes sticky. Drink plenty of water immediately before the flight and carry on board a full drink bottle of fresh water.

  • Avoid alcohol and coffee which may increase risk of DVT – their diuretic effects may dehydrate.

  • Avoid tobacco smoke and polluted air - carbon monoxide makes the blood sticky and reduces oxygenation. Ensure all flights are non-smoking.

  • Keep the legs warm if the air is cold - wrap up with a warm blanket and long thick socks. Blood is a bit like gravy – when it is cold it is sticky and congeals and doesn't flow freely.

  • Take daily up to 1,000 mg of vitamin C, 1,000 mg of natural vitamin E and up to 6,000 mg of fish oil or flax oil per day. Choose only naturally derived vitamins.

  • You could add specially formulated tissue salt preparations that contain minerals for circulation, including magnesium, instead of that mineral on its own. I recommend Active Elements 3.1 and Active Elements 4.3

  • Include brightly coloured berries, fruits and vegetables daily.

  • Athlete or not - follow a heart healthy diet.

  • Stressed? Then go do something relaxing like a long warm bath and a loving massage.

  • Athletes should avoid long distance travel within 36 hours after bruising contact sports or injury and should not take aspirin products within 12 hours before participating in bruising contact sports.

  • All athletes benefit from a nutritional programme to nurture their adrenal and thyroid glands - the glands that power athletic performance!

Your best defence to prevent DVT may be natural Vitamin E with fish oil

But is must be natural Vitamin E - nothing else.

It must read this on the product label: d-alpha tocopherol - if it does not read exactly as this, then do not take it.

Sleeping pills

It may be tempting to get some sleep during long haul flights by taking sleeping pills. While I can find no research on the subject, I am not comfortable with this practice for the following reasons:

  • The sedating effects of the medication may further depress already seriously compromised circulation during travel, by relaxing the blood vessels and reducing heart rate.

  • Being sedated, you may be even less inclined to get up, move about, stretch, or flex and extend the legs while sitting.

  • The half-life of the medication may be several hours or longer. With individual variations among people, you may still have significant traces of the medication in them the following day. This has important implications for physical and mental performance the following day.

  • There is little benefit in trying to induce deep sleep if this conflicts with the new sleeping and waking hours of the destination.

Upon Arrival

  • Immediately upon arrival at your destination, do half an hour or more of steady aerobic exercise to re-oxygenate the blood and flush the system.

  • You will benefit from gravity-assisted effleurage massage, such as where the legs are elevated above the body by a couple of pillows and the gentle massage is directed from toes to body. But do not massage if there is any suspicion of DVT present - consult a medical practitioner before proceeding.

  • Vigorous hydrotherapy is an extremely effective way to limber stiff, sore muscles while boosting lymphatic and venous flow. When selecting accommodation, give strong preference for facilities that include a warm chest-deep swimming pool.

  • If the travel has been across time zones, the first few days after arrival should include relatively light aerobic exercise to keep the circulation pumping.

  • If the athletic competition venue is more than 3-4 hours travel from base, plan to be there at least 36 hours earlier with accommodation organised. If this is not possible, break up the trip with exercise and refreshment stops, arrive early with arrangements in place to minimise standing around.

Sight-seeing and getting about

Be acutely aware of the possibility of incidental exposure to economy class syndrome. Getting about in unfamiliar, foreign countries can be so unlike home. What may appear on the map to be a 10 minute trip across town may turn out to be a four hour hell-journey – crammed in a sweaty vehicle, sucking on truck exhaust fumes! Carbon monoxide is a poisonous by-product of the internal combustion engine that makes the blood sticky - and it binds strongly with haemoglobin, rendering it incapable of transporting oxygen.

To stay healthy you need fresh, unpolluted air, so keep out of traffic, stay away from smokers and keep hydrated. Taking your sports team out to the movies in the evening might seem like a nice thing to do, but consider the length of the journey there and back, the one to two hours spent sitting in a stuffy theater and the possible late night. It may be better to hire a good video and show it where everyone can relax, stretch out and move about at will.

Coach and manager, a special warning to you - you’re probably older and less fit than your athletes and probably under extreme stress. (Stress hormones increase blood clotting rate). You are the ones in the entourage most likely to suffer DVT – and you’re more likely to suffer life-threatening complications. Be sure that these guidelines apply to yourselves, as much as to your athletes.

If you are already on medication for DVT

Another thought for those whose doctors dictate rather than advise and order long term coumadin (warfarin). Study the side effects they list.

Calcification in vital organs similar to the ones seen after long term Vit D overdose, both are based on Vitamin K deficit and treatable by Vit K. Imagine the dilemma though in warfarin users! They're advised not to have supplementary Vit K.

Vitamin E is worth your consideration and the best strategy for overall health is to take a combination capsule or two of the tocopherols PLUS the tocotrienols, which gets close to what nature provides us with.

The latter are found more in the grains so use your judgement or better find a knowledgeable health practitioner to advise you.

Recommended products for prevention and recovery:

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