High blood pressure can be caused by a number of things. Stress is probably the most common reason. When you are stressed out about things, it tends to wear your body out and you are that much more easily aggitated. When this happens, your blood pressure, just like your adrenaline, can start to rise. Another reason for high blood pressure can be poor diet. If you’re not eating foods that are good for you and provide a well balanced diet for yourself, this can boost your blood pressure up a bit.