The main factors that are known to cause essential hypertension are:

Heredity: If the parents or siblings have high blood pressure, there are more chances of developing high blood pressure yourself.
Ethnicity: Some ethnic groups like African Americans, are more prone to developing high blood pressure.

Lack of exercise: The lack of exercise increases the bad cholesterol levels with deposits forming on the artery walls. Since the effective cross section of the artery becomes smaller, the blood pressure is increased.

Obesity: Lack of exercise and unhealthy eating habits are known to cause obesity. However, regardless of why one is obese, one is at more risk of developing high blood pressure.

Alcohol or tobacco consumption: Having more than a couple of drinks every day increases the chances of developing high blood pressure. Similarly, intake of tobacco by smoking or other means, also increases the high blood pressure.

Stress: People who are normally stressed out are more prone to developing high blood pressure.

Sex: Males are more susceptible to develop high blood pressure than women.