Doctor reveals one silent symptom that can appear days before a heart attack strikes

A doctor has warned about subtle symptoms which could mean that you are about to have a heart attack.

The acute symptoms of a heart attack, that's the short-term symptoms, might be widely known, but there are also others which can be more difficult to spot.

If you have chest pain, intense anxiety, shortness of breath, or a crushing feeling in your chest, these are all signs of a heart attack.

Someone who has these symptoms should get medical attention as quickly as possible, because if you're having a heart attack, acting quickly could literally be the difference between life and death.

But there are other symptoms which could be a sign that a heart attack is imminent - and unfortunately, they are a lot easier to miss.

So what are they?

Speed is hugely important with treating a heart attack (Rawlstock/Getty)

Dr Obaidur Rahman recently took to Instagram to share a warning about these signs, and one sign in particular.

Dr Rahman said that as many as 92 per cent of people ignore this sign.

This is a condition called orthopnea.

If you know your medical terminology, you may already have guessed that the suffix '-pnea' refers to a condition related to breathing - for example, apnea or hypopnea.

Orthopnea is when someone finds it difficult to breathe when they are lying down.

Taking to social media, Dr Rahman explained: "When the heart weakens, blood backs up into the lungs.

"The moment you lie flat, gravity stops helping you breathe and you wake up suffocating, restless, drenched in sweat.

He added: "That’s not stress. That’s your body begging you to listen."

The acute symptoms of a heart attack are widely known (PhotoAlto/Frederic Cirou/Getty)

When you're standing up, blood is pulled down to your legs by gravity, away from your chest cavity.

But when you lie down, this is no longer the case, and blood moves into the chest area.

While this isn't an issue for a healthy heart, in someone who has heart disease, the extra pressure on the heart can be a big problem.

The doctor went on to explain that this can be made worse by lifestyle factors, writing: "And it’s happening to a generation raised on late nights, deadlines, skipped meals, energy drinks, and zero recovery.

"Because your heart doesn’t care about your ambition, it only cares about your oxygen."

Dr Rahman suggested that if you have ever 'had to sleep propped up on pillows just to breathe better' then you should go and get yourself checked out just to be on the safe side.