Countless TV dramas and films have taught us to instantly know that a character who grips their left arm, winces with crushing chest pain and collapses to the floor has just had a heart attack.
In real life it isn't always this way and, conversely, sometimes even the most distressing of chest pains are harmless. When the heart is starved of oxygen, it typically feels dull and 'heavy'; sometimes a bit like 'an elephant is sitting on your chest'.
It usually gets worse with exercise and stress, can move into either arm, and may be accompanied by sweating and/or breathlessness. Reach for the telephone if you feel these symptoms because a medic may need to give you a clot-busting drug to reverse the problem.
Sadly, most people put off calling for help. These life-saving drugs work best in the first hour - so every minute counts.