Travel health service
DVT and travel: lowering your risk on long journeys
Long flights and long sits can slightly raise your risk of a blood clot. Altrincham Travel Clinic in Timperley can fit graduated flight socks and offer a pre-travel risk assessment if you need one.
What it is
Should you worry about a blood clot on a long flight?
Deep vein thrombosis (DVT) is a blood clot that forms in a deep vein, usually in the calf or thigh. Sitting still for a long time — typically more than four hours, whether by plane, car, coach or train — slows the blood flow in your legs, which is why it's sometimes called "travellers' thrombosis". The reassuring news is that for most healthy travellers the overall risk is low: the NHS and TravelHealthPro put the chance of a clot after a long flight at roughly 1 in 6,000. A few simple habits lower it further.
This page is general information from Altrincham Travel Clinic, not personalised medical advice or a prescription. If you have risk factors for clots — or you've had a DVT or pulmonary embolism before — the right plan can be different for you, so it's worth a short pre-travel assessment with our pharmacist in Timperley. We can advise on flight socks, run through your history, and tell you when something needs your GP or a specialist.
Plan ahead
Higher risk? Get a pre-travel assessment before you fly
If you have one or more risk factors — a previous DVT or PE, a known clotting disorder, recent major surgery, active cancer, pregnancy, or you take oestrogen-containing contraception or HRT — it's worth a short pre-travel risk assessment a couple of weeks before you go. We'll talk through your history and journey, fit graduated flight socks, and tell you clearly if anything needs your GP or a specialist (for example, whether an anticoagulant injection might be advised).
Booking ahead means there's time to measure compression socks properly and to arrange any onward referral without rushing. Pop into Altrincham Travel Clinic in Timperley, near Manchester Airport, or book online.
The basics
What are DVT and pulmonary embolism?
A DVT is a clot in a deep leg vein. The main worry is that part of the clot can break off and travel to the lungs — a pulmonary embolism (PE), which is a medical emergency. On long journeys, immobility lets blood pool in the lower legs, and pressure from the seat edge behind the knee can add to it. Understanding the difference helps you know what to watch for and when to act.
- DVT = a clot in a deep vein, usually in one calf or thigh
- PE = a clot that has travelled to the lungs (an emergency)
- Long sits over ~4 hours slow blood flow and allow pooling
- Affects any long journey — air, car, coach or train
- For most healthy travellers the absolute risk stays low
Know your risk
What raises your risk of a travel clot?
Most people travel safely, but some factors make a clot more likely. The more that apply to you, the more worthwhile a pre-travel assessment becomes. This is general guidance — our pharmacist will check what's relevant to your own history and journey, and signpost you to your GP or a specialist where needed.
- A previous DVT or PE, or a close family history of clots
- A known clotting disorder (thrombophilia, e.g. Factor V Leiden)
- Recent major surgery or a serious leg injury
- Active cancer or current cancer treatment
- Pregnancy and the first six weeks after giving birth
- Oestrogen-containing contraception or HRT, obesity, older age, varicose veins or significantly reduced mobility
For every traveller
Simple things that lower your risk
Whatever your risk level, the same sensible habits help on any long journey. Keep your legs moving, stay hydrated and avoid anything that restricts your circulation. None of this needs a prescription — it's everyday self-care that makes a real difference on a long-haul flight or drive.
- Get up and walk about roughly every hour where you safely can
- Do calf and foot exercises in your seat — flex and point your ankles, circle your feet
- Drink plenty of water and go easy on alcohol, which dehydrates you
- Don't sit with your legs crossed for long, and wear loose, comfortable clothing
- Consider an aisle seat and keep cabin bags clear of your legroom
The product
Graduated compression flight socks
Graduated compression socks are firmer at the ankle and ease off up the leg, gently encouraging blood back towards the heart. There's good evidence they reduce travel-related clots and the ankle swelling many people get on long flights — most useful if you have moderate-to-higher risk. Fit matters: they should be below-knee, the correct size and a graduated compression class (TravelHealthPro references around 15-30 mmHg at the ankle). We can measure and supply the right ones at our Timperley pharmacy.
- Put them on before you set off and keep them on for the journey
- Designed to reduce clot risk and ankle/leg swelling on long trips
- Need the correct size and graduated compression — not ordinary tight socks
- Poorly fitting socks can dig in and actually hinder circulation
- Pop in and we'll measure you and advise on the right pair
Medication myths
Aspirin, blood thinners and what's actually advised
A common question is whether to take aspirin before flying. UK guidance (NICE) and travel-health authorities such as TravelHealthPro do not recommend aspirin to prevent travel clots — it doesn't reliably prevent venous clots and carries its own bleeding risk. Prescription blood thinners such as a low-molecular-weight heparin injection are only for specific high-risk people, and only on a doctor's or specialist's advice. If that might be you, get assessed rather than self-treating.
- Aspirin is not routinely recommended just for flying
- Never start aspirin or any blood thinner for travel without advice
- Anticoagulants are reserved for higher-risk individuals only
- If you already take an anticoagulant, keep taking it as prescribed
- Higher risk? A pre-travel assessment is the safe first step
When to act
Symptoms to take seriously
Most clots that do occur appear in the days or couple of weeks after a long journey, not always on the plane itself. Know the warning signs. DVT symptoms are usually in one leg; a pulmonary embolism is an emergency and needs immediate help. If in doubt, get it checked — clots are very treatable when caught early.
- DVT: pain, swelling, warmth or redness, usually in one calf or leg
- Skin may look discoloured and the area can feel tender or hot
- PE (emergency): sudden breathlessness, or chest pain that's worse when you breathe in
- PE (emergency): coughing up blood, or feeling faint — call 999
- Don't wait it out — seek urgent medical care if you're worried
Red flags
DVT or PE? Know the difference
Use this quick guide to tell apart a possible leg clot from a lung emergency. When symptoms point to a PE, treat it as a 999 emergency — don't drive yourself.
Possible DVT — get it checked promptly
Pain, throbbing, swelling, warmth or redness, usually in one calf or thigh. The skin may look discoloured. Contact your GP, NHS 111 or seek urgent advice the same day.
Possible PE — call 999 now
Sudden shortness of breath, chest pain that worsens when you breathe in, coughing up blood, a fast heartbeat or feeling faint. This is a medical emergency — call 999.
After a long trip, stay alert
Symptoms can appear up to a few weeks after travelling, not just in the air. If you develop leg or breathing symptoms after a long journey, mention the travel to whoever assesses you.
Higher-risk traveller? Plan first
If you've had a clot before, have a clotting disorder, are pregnant or recently had surgery, book a pre-travel assessment so we can tailor advice before you fly.
FAQ
DVT and travel — frequently asked questions
Travelling far and want peace of mind about clots?
Book a quick pre-travel risk assessment at Altrincham Travel Clinic in Timperley, near Manchester Airport. We'll fit graduated flight socks and tailor advice to you.