TALKING MEDICINE : Factors that lower your blood pressure

Low blood pressure, also called hypotension, is when your blood pressure lowers down and causes inadequacy of the blood flow to the body organs as well as manifesting with symptoms such as light headedness, dizziness, and even fainting.
Also a reading which is less than 90/60mmHg is termed as low blood pressure.
Hypotension has many possible causes—from lifestyle choices, to medication or an underlying health condition.
It is normal for your blood pressures to vary throughout the day depending on the activities that you are doing.
Furthermore, blood pressure depends on the surrounding environment and temperature. In hot weather, people tend to exhibit low blood pressure.
Similarly what and when you have eaten could all affect your blood pressure readings.
If your blood pressure is still considered low after taking these factors into account, other causes are as follows;

•  Inherited; Research has suggested low blood pressure is genetic.
  
•  Age; Your blood pressure usually increases as you get older, but a drop in blood pressure from movement or eating is more common in  young age.
•  Medications; some types of medication may cause low blood pressure, including antihypertensive drugs.
•  Dehydration; Dehydration can occur if fluid is lost, either through skin from excessive sweating in hot weather, or from vomiting or diarrhea.
•  An illness or underlying health condition such as anaemia.
•  Change of posture; from sitting or lying to standing  tend to lower blood pressure.
•  Serious injury such as major trauma or burns, particularly if you lose a lot of blood.
•   Shock; During an allergic reaction, your body produces a large amount of chemical called histamine, which causes your blood vessels to widen, leading to a sudden severe drop in blood pressure.