Blood pressure can increase for reasons other than simply aging. We know that diet, lifestyle and stress are major factors in causing hypertension. For example, a person who eats a lot of sodium is at risk, as is a person who drinks a lot of alcohol or who does not get enough exercise.
Please use this link to see more risk factors for hypertension.
The blood pressure is increasing when the arterial walls are thickening. Also, when we are growing old, the arterial walls become less elastic.
The increasing of blood pressure is called hypertension. If the increasing is very high, the arteries cannot take the pressure and they are breaking causing internal bleeding.
The hypertension could be detected using an instrument of measure called sphygmomanometer.