Symptoms: Recognizing DVT and Pulmonary Embolism
DVT symptoms (typically in one leg):
Important: DVT can be entirely asymptomatic. Some patients have no leg symptoms at all and present directly with pulmonary embolism.
Pulmonary Embolism symptoms — MEDICAL EMERGENCY:
If you or someone near you develops these symptoms — especially in the hours or days after a long flight — call 119 immediately or go to the nearest emergency room. Pulmonary embolism can be fatal within hours without treatment.
Prevention: Before, During, and After the Flight
Before your flight:
- Consult your doctor if you have multiple risk factors — anticoagulation or compression therapy may be recommended
- Purchase compression stockings (弾性ストッキング, *dansei sutokkingu*): Class 2 graduated compression stockings (15–30 mmHg or higher) are the most evidence-based prevention measure available without a prescription
- Available at Japanese pharmacies (松本清, ウエルシア, etc.) and airport shops
- Put them on before boarding, not after symptoms appear
- Prescription anticoagulants: For highest-risk individuals, injectable low-molecular-weight heparin (enoxaparin) or oral anticoagulants may be prescribed by your doctor before departure
During the flight:
In-seat leg exercises (do every 30–60 minutes):
- Ankle circles: rotate both feet clockwise and counterclockwise, 10 repetitions each
- Ankle pumps: flex feet up toward knees, then point down, 20 repetitions
- Knee lifts: alternately lift knees to chest while seated, 10 each side
- Calf muscle contractions: squeeze and release calf muscles repeatedly
After your flight — especially for high-risk travelers:
- Avoid sitting still for extended periods immediately after landing
- Continue wearing compression stockings for 24 hours
- Stay active — walking in Japan's cities involves significant natural leg exercise
- Stay well hydrated, especially in Japan's summer heat
- Watch for DVT symptoms for the first 2–4 weeks after a long-haul flight (risk remains elevated for up to 4 weeks)
If You Suspect DVT in Japan: Where to Get Help
Do not massage a suspected DVT clot — this can dislodge it and cause pulmonary embolism.
Do not fly again until DVT has been ruled out or anticoagulation treatment has been established.
Immediate steps:
- Elevate the affected leg
- Go to a clinic or hospital for evaluation
- Call 119 if pulmonary embolism symptoms are present
Tests performed in Japan for suspected DVT:
Treatment if DVT is confirmed in Japan:
DVT treatment requires anticoagulation therapy:
- Direct oral anticoagulants (DOACs): Rivaroxaban (リバーロキサバン / イグザレルト) or apixaban (アピキサバン / エリキュース) — widely used in Japan; may be initiated for confirmed DVT
- Low molecular weight heparin (LMWH): Injectable; used in hospital settings
- Warfarin (ワルファリン): Older oral anticoagulant; requires INR monitoring
If DVT is diagnosed, you will likely need to remain in Japan under medical care until stable, and flying home may need to be postponed or require medical clearance. This is a critical situation where comprehensive travel insurance becomes essential — ensure your policy covers treatment and medical repatriation if needed.
Which Department to Visit and How to Find a Clinic
- 救急外来 (Kyūkyū Gairai) — Emergency room: for pulmonary embolism symptoms or sudden severe DVT
- 内科 (Naika) — Internal Medicine: for evaluation of suspected DVT without emergency symptoms
- 循環器内科 (Junkanki Naika) — Cardiology: if PE is suspected alongside DVT
- 血管外科 (Kekkan Geka) — Vascular Surgery: for severe DVT requiring intervention
In major Japanese cities, most hospitals have vascular ultrasound available for same-day or next-day DVT evaluation during business hours.
Use Traveler's Hospital to find hospitals with internal medicine or vascular services near your location in Japan.
Cost Estimate
Hospitalization in Japan for serious conditions can be very expensive without insurance. Comprehensive travel insurance with medical evacuation coverage is strongly recommended for long-haul travelers with DVT risk factors.
Japanese Phrases to Use at the Clinic or Emergency Room
Related Resources
Frequently Asked Questions
Q: How common is DVT on flights to Japan?
A: The absolute risk of DVT for a single long-haul flight is low for healthy travelers — estimated at approximately 1 in 6,000 flights for symptomatic DVT. However, for high-risk individuals (previous DVT, active cancer, pregnancy, multiple risk factors), the risk is substantially higher. The risk is also cumulative over a trip involving multiple long flights.
Q: Are compression stockings really effective for DVT prevention?
A: Yes. Multiple randomized controlled trials have demonstrated that graduated compression stockings significantly reduce the incidence of DVT on long-haul flights in high-risk travelers. They are the most evidence-based intervention available without a prescription. Ensure you use proper graduated compression stockings (not just regular travel socks) with at least 15–30 mmHg pressure at the ankle.
Q: Should I take aspirin to prevent DVT on my flight to Japan?
A: Current evidence does not support aspirin use for DVT prevention on flights. Aspirin works primarily against arterial clots (heart attacks, strokes) rather than venous clots (DVT). For high-risk individuals, discuss low-molecular-weight heparin (LMWH) injections with your doctor before travel — this is the appropriate pharmacological prophylaxis for DVT.
Q: Can I fly back home if I have DVT?
A: Flying with an untreated DVT is dangerous due to the risk of clot dislodgement and pulmonary embolism during flight. If DVT is confirmed, you generally need to be established on anticoagulation therapy and clinically stable before flying. The decision should be made by the treating physician in Japan in consultation with your home country's medical team.
Q: What is the "economy class syndrome" and is business class safer?
A: Economy class syndrome (エコノミークラス症候群) is the Japanese-coined term for DVT associated with long-haul flights. It was named "economy class" because the cramped seating restricts movement more than in business or first class. Business class and first class do provide more space and make movement easier, and there is some evidence suggesting lower DVT risk compared to economy class. However, DVT can occur in any class of seating — mobility and hydration are more important than class.
Q: I had DVT diagnosed in Japan. What should I do next?
A: Stay calm and follow the Japanese doctor's treatment plan. Ensure you have comprehensive travel insurance and notify your insurer immediately — they can assist with coordination of care and potential repatriation if needed. Contact your home country embassy or consulate if you need consular assistance or help communicating with your insurer. Get a written clinical summary (診断書) and all test results in both Japanese and English (the doctor or hospital can usually arrange translation or provide English summaries).