Shortness of Breath
Another possible sign of a heart attack is shortness of breath. This is caused when your blood vessels get backed because of an unhealthy cardiovascular system, which spreads to other parts such as your lungs. In most case, you might experience breathlessness during an activity, at rest, or during sleep, which might come on unexpectedly and wake you up. Also, you have to be propped up due to difficulty breathing when lying flat. [8]
