Nausea
A heart attack may cause nausea, which is twice as likely to occur in women than in men (many also feel like they’re getting the flu days before a heart attack). If you have sudden and constant nausea that doesn’t seem food related, take action.
Shortness of breath
If workouts inexplicably seem harder, see your doctor. If you suddenly feel like you just ran up stairs and can’t catch your breath when you’re not doing much, or the feeling rouses you from sleep, go to the ER.