The NHS is urging people to be aware of a symptom in the legs that could indicate a potentially deadly health issueFiona Callingham Lifestyle writer, Dan Taylor and Tom Kershaw Content Editor
06:22, 27 Sep 2025Updated 06:22, 27 Sep 2025
The NHS is urging people to be aware of a symptom in the legs that could indicate a potentially deadly health issue(Image: Justin Paget via Getty Images)
The NHS is cautioning people to watch for an uncomfortable symptom in the legs that could signal a potentially fatal health condition. The health service states that leg swelling serves as a red flag for heart failure, reports the Mirror.
This condition, referred to as oedema, can also affect the feet and ankles, making walking difficult. The NHS notes that this symptom may ease in the morning but “get worse later in the day”.
Heart failure occurs when the heart battles to pump blood around the body efficiently. It’s usually caused by the heart becoming too frail or stiff. The NHS states: “Heart failure is a long-term condition that tends to get gradually worse over time. It cannot usually be cured, but the symptoms can often be controlled for many years.”
Experts from Medical News Today explain that heart failure causes elevated blood pressure in the blood vessels as the heart isn’t functioning as effectively as it should. “This elevation in pressure forces fluid out of the blood vessels and into the surrounding tissues, resulting in swelling, or oedema,” they explained.
Oedema might appear like:
Swollen or puffy ankles, feet or legsShiny or stretched skinChanges in skin colour, discomfort, stiffness and dents when you press on the skin
It can also be triggered by:
Standing or sitting in the same position for too longEating too much salty foodBeing overweightBeing pregnantTaking certain medicines – such as some blood pressure medicines, contraceptive pills, Hormone therapy, antidepressants or steroidsAn injury – such as a strain or sprainAn insect bite or stingProblems with your kidneys or liverA blood clotAn infection
(Image: boonchai wedmakawand via Getty Images)
Additional signs of heart failure include:
Breathlessness – this may occur after activity or at rest; it may be worse when you’re lying down, and you may wake up at night needing to catch your breathFatigue – you may feel tired most of the time and find exercise exhaustingFeeling lightheaded and faintingA persistent cough, which may be worse at nightWheezingA bloated tummyLoss of appetiteWeight gain or weight lossConfusionA fast heart rateA pounding, fluttering or irregular heartbeat (palpitations)
Some people with heart failure may also experience feelings of depression and anxiety. The NHS recommends: “See your GP if you experience persistent or gradually worsening symptoms of heart failure.
“Call 999 for an ambulance or go to your nearest accident and emergency (AandE) department as soon as possible if you have sudden or very severe symptoms.”