A heart attack happens if the flow of oxygen-rich blood to a section of heart muscle suddenly becomes blocked and the heart can't get oxygen. Most heart attacks occur as a result of coronary heart disease (CHD).

CHD is a condition in which a waxy substance called plaque builds up inside of the coronary arteries. These arteries supply oxygen-rich blood to your heart.

When plaque builds up in the arteries, the condition is called atherosclerosis. The buildup of plaque occurs over many years.

Eventually, an area of plaque can rupture (break open) inside of an artery. This causes a blood clot to form on the plaque's surface. If the clot becomes large enough, it can mostly or completely block blood flow through a coronary artery.

If the blockage isn't treated quickly, the portion of heart muscle fed by the artery begins to die. Healthy heart tissue is replaced with scar tissue. This heart damage may not be obvious, or it may cause severe or long-lasting problems.

Heart attacks can start slowly and cause only mild pain or discomfort. Symptoms can be mild or more intense and sudden. Symptoms also may come and go over several hours. People who have high blood sugar (diabetes) may have no symptoms or very mild ones. The most common symptom, in both men and women, is chest pain or discomfort. Women are somewhat more likely to have shortness of breath, nausea and vomiting, unusual tiredness (sometimes for days), and pain in the back, shoulders, and jaw.

1. Extreme fatigue In the days or even weeks before a heart attack, more than 70% of women experience debilitating, flulike exhaustion. You may suddenly feel too tired to cook dinner or lift your laptop.

2. Mild pain Rather than the elephant on the chest, women may feel less severe pain—and not always in the region of the heart. Pressure or achiness can occur in the breastbone, upper back, shoulders, neck, or jaw.

3. Profuse sweating You may find yourself suddenly drenched in perspiration for no apparent reason, or your face may be pale or ashen.

4. Nausea or dizziness Prior to a heart attack, women often have indigestion or even vomit. You may also feel like you're about to pass out.

5. Breathlessness Almost 58% of women report panting or inability to carry on a conversation because they couldn't catch their breath.