Heart attacks occur when the supply of blood to the heart is suddenly blocked, usually by a blood clot.
If you suspect a heart attack you should call 999 immediately as potential complications can be life-threatening.
But a heart attack can be prevented from happening in the first place by making some easy lifestyle changes.
One of these is eating a healthy and balanced diet, slashing the levels of bad cholesterol in the blood.
You can reduce your cholesterol levels further by including nuts in your diet - but how many should you be eating a day?
All nuts are rich in vegetable protein, fibre, heart healthy unsaturated fats, vitamin E, magnesium, potassium, natural plant sterols and a host of beneficial plant nutrients, according to Heart UK.
It recommends you eat 30 to 35g a day of nuts (about a handful) as this has the potential to lower cholesterol by an average of five per cent.
A 30 to 35g of individual nuts looks like:
- 32 almonds
- 10 Brazils
- 28 cashews
- 4 chestnuts
- 21 hazelnuts
- 21 macadamias
- 28 peanuts
- 35 pistachios
- 11 walnut halves
Other foods which can help lower cholesterol are soya foods, such as soya alternatives to milk and yoghurt, soya desserts, soya meat alternatives, soya nuts, edamame beans and tofu.
The heart charity explains: “Being natural low in saturated fat, soya foods help lower cholesterol.
“The special proteins in soya also appear to influence how the body regulates cholesterol too.
“Studies show you can lower your cholesterol by around six per cent by including as little as 15g soya protein per day.”
Oats and barely can also lower cholesterol as they are rich in a form of soluble fibre called beta gluten.
The charity says: “Once eaten beta flacon forms a gel which helps bind cholesterol in the intestines and prevent it from being absorbed.
“It is recommended that we eat about 3g of beta gluten per day.
“Foods which contain 1g or more of beta gluten can carry a cholesterol lowering claim.”
One of the most common symptoms of a heart attack, the NHS notes, is pain in a particular part of the body - the chest.
It says: “The chest can feel like it's being pressed or squeezed by a heavy object, and pain can radiate from the chest to the jaw, neck, arms and back.”
But pain can also occur in other parts of the body.