Diastolic heart failure occurs when the left ventricle of your heart becomes stiffer than normal, making it difficult for your heart to relax and fill with blood properly. This results in less blood being pumped out to your body. Common causes include aging, high blood pressure, diabetes, coronary artery disease, and obesity. Symptoms can include shortness of breath, fatigue, and swelling in the legs. While there is no cure, treatment can help manage symptoms and improve heart function. Treatment plans often include lifestyle changes such as a healthy diet, regular exercise, and quitting smoking, as well as medications to help the heart pump more effectively.