I always hear about the concerns of high blood pressure, but what about low blood pressure?

Depending : If people has no symptoms while his/her blood pressure is low, that might be normal for that specific person. If low blood pressure associates with symptoms, like dizziness, raising heart beat, sweating or tire, etc., then further check up by a physician is needed. It may caused by dehydration, imbalance of electrolytes, endocrinological disorders, etc.