Call 911 or emergency medical help if you think you or someone else might be having a heart attack.

Symptoms of a heart attack may include:

• Chest pain that may feel like pressure, tightness, pain, squeezing or aching.
• Pain or discomfort that spreads to the shoulder, arm, back, neck, jaw, teeth or sometimes the upper belly.
• Cold sweats.
• Fatigue.
• Heartburn or indigestion.
• Lightheadedness or sudden dizziness.
• Nausea.
• Shortness of breath.

A heart attack usually causes chest pain that lasts more than 15 minutes. The chest pain may be mild or severe. Some people don't have any chest pain or pressure. Symptoms may be less obvious in some people, especially for women. For example, heart attack symptoms may include nausea or a brief or sharp pain felt in the neck, arm or back.

Some heart attacks happen suddenly. But many people have warning signs hours or days in advance.

• Call 911 or your local emergency number. Don't ignore the symptoms of a heart attack. If you can't get an ambulance or emergency vehicle to come to you, have someone drive you to the nearest hospital. Drive yourself only if you have no other option.
• Take aspirin, if recommended. Aspirin helps prevent blood clotting. Taking aspirin during a heart attack may reduce heart damage. Don't take an aspirin unless a healthcare professional says to do so. Don't delay calling 911 to take an aspirin. Call for emergency help first.
• Take nitroglycerin, if prescribed. If you think you're having a heart attack and you have a prescription for this medicine, take it as directed while waiting for emergency medical help.
• Start CPR if the person doesn't have a pulse or isn't breathing. If you're untrained in CPR, do hands-only CPR. That means push hard and fast on the person's chest. Do this about 100 to 120 times a minute. If you're trained in CPR and confident in your ability, start with 30 chest compressions before giving two rescue breaths.
• Use an automated external defibrillator (AED) if one is available and the person is unconscious. The device delivers shocks to reset the heart rhythm. AEDs come with step-by-step voice instructions for their use. They're programmed to allow a shock only when appropriate.

Lifestyle changes can keep the heart healthy and may help prevent a heart attack.

• Don't smoke or use tobacco.
• Get regular exercise.
• Keep a healthy weight.
• Eat nutritious foods and use less salt and saturated fats.
• Limit alcohol.
• Manage stress.
• Control blood pressure, blood sugar and cholesterol.
• Get 7 to 8 hours of sleep daily.

Also it's a good idea to learn CPR and how to use an AED so you can help someone who's having a heart attack. Ask your healthcare team if any accredited first-aid training courses are available in your area.