4. FATIGUE.
Feeling worn out after a sleepless night or a stressful day is normal. But women can feel fatigued a month out before having a heart attack, Harvard Health Publishing reports. According to the National Heart, Blood, and Lung Institute, this sign is especially prominent in women.

5. NAUSEA OR INDIGESTION.
According to Stoney Brook Medicine, gastric symptoms like a queasy stomach, vomiting, or belching develop when the heart and other areas of the body aren’t receiving enough blood supply. It can be misjudged as acid reflux or heartburn, so it’s important to reach out to your doctor, especially if you’re having other heart attack symptoms.