If a person has a blood pressure reading that is 85/55 millimeters of mercury or lower and experiences dizziness, fatigue or fainting spells, then this can be indicative of low blood pressure or hypotension, states the American Heart Association. Some other symptoms associated with hypotension are clammy skin and thirst.
In many cases, hypotension without symptoms is not serious, according to Mayo Clinic. If a person has consistent low blood pressure readings and has symptoms, then he should see his doctor because it may indicate a more serious health problem. Similarly, a rapid decrease in blood pressure may indicate a serious condition, such as a severe infection or extensive blood loss, according to the AHA.
Some causes of hypotension include pregnancy, heart conditions, medications, thyroid problems, dehydration and nutritional deficiencies, reports Mayo Clinic. Furthermore, there are different types of hypotension that include postural and postprandial hypotension. Postural hypotension occurs when a person gets up after being in a prone or seated position. Postprandial hypotension can happen after eating a meal.
Keeping a record of blood pressure readings can help identify consistently low blood pressure readings, notes the AHA. People can use a blood pressure monitor that measures the systolic and diastolic pressures for this purpose. An optimal reading is below 120/80 millimeters of mercury, where 120 is the systolic pressure and 80 is the diastolic pressure.