Hi let me just speak with you briefly about what is a low blood pressure reading. I am going to give it to you as an adult, teen, child, infant. In an adult as we know 120/80 is usually considered to be normal. Anything below 117/70 could be on the abnormal side of being a low blood pressure reading but not always it just tends to be somewhat lower. A teenager might show 116/70 which was considered to be a teenager from 12 to 17 years of age. If a child is considered to be age 12 years of age, their blood pressure might be 104 to 106/58 to 61 which is normal however, if it is below those numbers then you would be looking to see what might be causing the low blood pressure. With an infant anything below 50 to 70 on the systolic and 25 to 45 on the diastolic which is the bottom number. You would be looking to see why that child has such a low blood pressure. Now you have to take into special consideration that people who exercise a lot are going to have a low blood pressure and people who are thinner, don't eat as much sodium and some of the things that we do to ourselves will have a lower blood pressure, however, if it is consistent for a period of time and you can't figure out why it would be so low and you are feeling fainted or you don't feel well and you feel so tired I would call the physician and tell him that you need to see him regarding blood pressure that has been reading rather low for a period of time.