Doctors consider blood pressure under 90/60 low, according to WebMD. Low blood pressure often is not serious but can sometimes indicate an underlying condition that requires medical evaluation.
Common symptoms of low blood pressure include dizziness, lightheadedness and fainting, which often occur when individuals transition from a lying or sitting position to a standing position, explains MedicineNet. Mild dehydration from time in the sun or in a hot tub can also cause these symptoms, states Mayo Clinic.
Low blood pressure commonly occurs during the first few weeks of pregnancy, after bed rest and in response to certain medications and other conditions.
A physician usually monitors a patient with consistently low blood pressure readings without signs or symptoms, notes Mayo Clinic. Blood pressure that drops rapidly or is accompanied by blurred vision, nausea, shallow breathing, fatigue or thirst can indicate a serious underlying condition. Blood pressure too low to provide adequate blood flow to the organs can cause heart attacks, strokes, kidney failure and shock, according to MedicineNet.