Signs of low blood pressure include fainting, blurred vision, nausea, thirst, dizziness and a lack of concentration, according to Mayo Clinic. Often low blood pressure has no symptoms. There is usually an underlying cause if severe symptoms of low blood pressure occur.
Optimal blood pressure for an adult is 120/80 mm Hg, as reported by the American Heart Association, or AHA. The systolic pressure, or the first number, should not be greater than 120. The diastolic pressure, or the second number, should be less than 80. Some people naturally have low blood pressure, which is considered to be around 85/55 mm Hg. If the person is not experiencing any negative side effects, the AHA says often his or her physician will simply monitor the blood pressure on an annual basis.
When symptoms of low blood pressure appear, however, is when it may be a cause for concern. When the blood pressure is too low, the body may not receive enough oxygen to function correctly, as stated by WebMD. The AHA lists some underlying issues that may cause low blood pressure:
- Lengthy bed rest, perhaps due to illness or recovery from surgery
- Blood pressure may drop at some point in the first 24 weeks of pregnancy
- Significant blood loss from trauma
- Certain medications
- Nutritional deficiencies, such as a lack of B-12 or folic acid