Breathing exercises alter physiology by changing blood carbon dioxide concentration, heart rate, and blood pressure. This is usually a good thing. For those with high blood pressure and heart disease, decrease in blood pressure may produce lightheadedness or dizziness. Therefore medication may need adjustment and awareness and approval by a physician or other healthcare provider is essential before you begin. Most healthcare providers will be happy to hear that you are doing breathing exercises and should encourage you to take positive steps toward health. Seizures can be triggered by hyperventilation, and relaxation abdominal breathing (exhale longer than inhale) is a way to prevent seizures. How to Prevent Many Seizures in 2-3 Minutes (Simple Breathing Exercise)