Episode 24 | Ask the Expert | Guest: Dr Ajai Seth MBBS, BSc, MSc, MRCS, MRCGP, FFSEM – Consultant in Sports and Exercise Medicine, Founder and Medical Director, LBSM
Compression garments are everywhere – from marathon start lines to long-haul flights. But not all compression is equal, and wearing the wrong type can do more harm than good. Dr Ajai Seth cuts through the marketing and explains what compression actually does, when it helps, and when to seek medical advice before buying.
Walk into any running shop or scroll through any sports brand’s website and you’ll find compression garments marketed as performance-enhancing, recovery-boosting, and injury-preventing. Some of those claims are backed by evidence. Others are not. And the difference between a helpful garment and a potentially harmful one comes down to understanding what you’re buying and why.
In this episode of the London Bridge Sports Medicine podcast, LBSM founder and Medical Director Dr Ajai Seth gives a clear, clinically grounded overview of compression garments – how they work, who needs them, and the important safety considerations that the product packaging rarely mentions.
The four main reasons to wear a compression garment
Dr Seth identifies four distinct reasons someone might use compression:
- Performance and recovery – enhancing cardiovascular efficiency during exercise, improving endurance, reducing delayed onset muscle soreness (DOMS), and speeding recovery between sessions
- Medical use – prescribed by a clinician to manage conditions such as varicose veins, deep vein thrombosis (DVT), or chronic leg swelling
- General support – providing a sense of muscular security, managing mild joint swelling, or supporting tendons during activity
- Travel – reducing the risk of leg swelling and DVT on long-haul flights. One important clarification here: the novelty socks handed out by airlines are not compression garments. They provide no meaningful compression and should not be relied upon for this purpose.
How compression actually works
Blood circulates around the body in a pressure system. Arteries carry oxygenated blood from the heart to the limbs under high pressure. Veins return that blood – along with waste products such as lactic acid – back to the heart, but at much lower pressure. Veins rely heavily on surrounding muscle contractions to push blood upwards against gravity.
This is why people who stand still for long periods get swollen ankles – the calf pump is underused, and blood pools in the lower limbs. Compression garments work by applying external pressure to the limb, supporting venous return and making the whole circulatory system more efficient during and after exercise. Dr Seth refers to this as improving venous return.
The same principle applies in the arms. Upper limb compression is relevant not only for medical conditions affecting arm circulation, but also for sports that demand significant upper limb effort – tennis, volleyball, and similar – where garments can support both performance and recovery in the arms as effectively as in the legs.
Graded vs. non-graded: understanding compression levels
Not all compression is the same, and this is where the consumer market gets confusing. Dr Seth distinguishes between two types:
- Non-graded compression – uniform pressure throughout the garment. This is what most high-street sports brands (Nike, Skins, and similar) produce. Generally light compression, primarily useful for the tactile sensation of muscular support and warmth. Limited evidence for physiological benefit given how light it is.
- Graded compression – graduated pressure that increases from the top of the garment downwards, directing blood flow back towards the heart. This is where meaningful clinical and performance benefit lies.
In the UK, graded compression garments are regulated to a British standard and classified by pressure level, measured in millimetres of mercury (mmHg):
- Class 1 – light support
- Class 2 – medium support
- Class 3 – strong support
British standard garments are also tested across multiple wash cycles (typically 500–600) to confirm they maintain their pressure over time. Non-regulated sports brand garments carry no such guarantee – meaning compression may degrade quickly with regular washing.
Can the wrong compression garment cause harm?
Yes – and this is the point Dr Seth is most emphatic about. Applying too much compression in the wrong circumstances can restrict arterial blood flow to the limb, potentially causing serious circulatory problems.
Anyone with known arterial disease – reduced blood flow through the arteries – should not use anything above a light (Class 1) garment without medical assessment. Before prescribing a higher-grade garment, Dr Seth typically conducts investigations including pulse checks, ultrasound scanning of blood flow, and ankle-brachial pressure index (ABPI) testing, which compares blood pressure readings in the arm and leg.
His clear guidance: light, non-graded compression from a sports retailer is generally fine for healthy individuals wanting basic support. Anything above that warrants a conversation with a clinician first.
Practical tips: getting the most from compression
- For exercise: garments can be worn during warm-up, through the session, and in the recovery period afterwards
- For travel: put garments on at least four hours before a long flight to allow time to take effect
- Don’t sleep in them: legs are naturally elevated when lying down, reducing the need for compression. Keeping them on overnight also unnecessarily depletes the garment’s elastic properties
- Avoid wearing continuously for days at a time: give the skin regular rest periods
- Buy two pairs: rotating between them preserves the life of each garment and ensures one is always clean
- Replace regularly: even quality garments lose compression effectiveness over time. Dr Seth recommends replacing every three to six months with regular use
- Get measured properly: compression garments only work if they fit correctly. Ill-fitting garments – too loose or too tight – either provide no benefit or create risk
The bottom line
Compression garments can offer genuine benefits for performance, recovery, and circulation – but only if you’re using the right type for your purpose. The light, non-graded sports compression widely available on the high street is low-risk and provides some tactile benefit, but its physiological impact is limited. For meaningful compression – whether for serious training, medical management, or travel – a properly graded, British standard garment, fitted and chosen with clinical guidance, is worth the investment.
And if you have any history of circulatory problems, seek advice before going above Class 1. The gains are not worth the risk of getting it wrong.
Dr Ajai Seth (MBBS, BSc, MSc, MRCS, MRCGP, FFSEM) is a Consultant in Sports and Exercise Medicine and the founder and Medical Director of London Bridge Sports Medicine. He sees patients across LBSM’s London clinic sites.
To book an appointment with Dr Seth or another member of the LBSM team, visit lbsm.co.uk/booking
Listen to the full episode below ↓
