Blood pressure in healthy adults ranges from 90/60 mmHg to 120/80 mmHg. Blood pressure below 90/60 mmHg is considered low blood pressure. In many cases, low blood pressure is benign and does not cause obvious symptoms, according to the health website Healthline (USA).

Low blood pressure is only dangerous when it drops below 90/60 mmHg and is accompanied by unusual symptoms. These symptoms include dizziness , nausea, fainting, feeling tired even after getting enough sleep, headache, blurred vision, heart beating too fast or too slow.

Low blood pressure can happen for many different reasons. Most people with low blood pressure do not have any signs or symptoms. They may not even realize that their blood pressure has dropped too low.

Certain medical conditions can cause low blood pressure, such as diabetes, heart disease, hypothyroidism, or certain neurological conditions, such as Parkinson's disease. People with Addison's disease, a condition in which the adrenal glands fail to produce enough of the hormone cortisol, are also prone to low blood pressure.

Not only illness, but also some problems can cause low blood pressure, such as dehydration, lack of nutrients such as vitamin B12 or folic acid. In addition, some medications such as beta blockers, erectile dysfunction drugs containing nitroglycerin or narcotics can also cause low blood pressure.

Sometimes, low blood pressure can also occur as a result of life-threatening conditions such as septic shock, severe allergies, or blood loss. Septic shock occurs when a person has a severe infection that affects their ability to circulate blood, leading to low blood pressure.

Allergies are quite common. Many of us have some form of allergy, such as to foods, chemicals, dust, mold, or pollen. However, severe allergies can cause anaphylactic shock, which can affect your circulation and lower your blood pressure.

Eventually, severe injuries can cause severe internal bleeding, causing excessive blood loss. This can lead to reduced blood circulation and low blood pressure, according to Healthline .