A heart surgeon has explained a sign that you shouldn’t ignore when it comes to your heart health.

If you’re going to take anyone’s advice over a major organ in your body that keeps everything up and running – it’ll be from someone who works to repair it every day.

Dr Jeremy London, who often shares his tips and tricks for living a more healthy life, was asked by his son about the biggest ‘red flag’ of a heart attack, to which he uttered a perhaps surprising answer.

As someone who has suffered a heart attack himself after ignoring key warning signs, he knows just how important it is to prevent the worst.

Prior to his own attack, the doctor was suffering from fatigue, low energy, what felt like heartburn and a sharp pain in his chest.

Dr Jeremy London revealed his 'red flag' 

While all three aren’t good signs, he went on to tell his son in the social media video that feeling like you’re struggling for breath and having chest pains during times of exertion, are both things not to ignore.

He said if things get better with rest, and only flare when you’re say, working out, you need to have an ‘honest’ conversation with yourself about your lifestyle.

He explained: "What's one piece of life-saving advice that could prevent someone from having a massive heart attack?”

Revealing he’s not talking about running ‘a marathon’, the doc said if you’re struggling when ‘taking out the trash’ or ‘going up a flight of stairs’, it’s your body trying to warn you about what’s looming ahead.

“Cause what’s happening is, with an important blockage, as you exert yourself, the heart muscle below is not getting enough oxygen and nutrients,” Dr London said, adding that when ‘you sit down, heart rate comes down, and the symptoms are received.’

He said if you get the symptoms during exertion, it's a red flag 

While people may say this is part of ‘getting older’, the expert explains they are danger signs that the body is trying to communicate about your health.

He said in the YouTube video: "Now, most people just shrug this off as 'I'm getting older' or they scale their lifestyle.

“They park closer at the grocery store. They take the elevator. But these are warning signs.

"You need to have some intellectual honesty about what your body is telling you. And remember, denial is not a river in Egypt.”

According to the Mayo Clinic, signs of a heart attack can include:

• Chest pain (pressure, tightness, pain, squeezing or aching)
• Pain or discomfort that spreads (shoulder, arm, back, neck, jaw, teeth or upper belly)
• Cold sweat
• Fatigue
• Heartburn or indigestion
• Light-headedness or sudden dizziness
• Nausea
• Shortness of breath

If you have these symptoms, it’s important to seek help and advice.