The higher number, called systolic, shows the highest amount of pressure on the walls of blood vessels during each beat of the heart. The lower number, diastolic, shows the amount of pressure on the arteries when the heart is resting between beats. Various things can temporarily affect blood pressure, so it is usually best to take an average of many measurements rather than use only one. When some people go to a clinic their anxiety can cause blood pressure to be much higher than normal, a condition called white-coat hypertension . Recent use of coffee or tobacco can raise blood pressure.
Many medications can raise or lower blood pressure.
Age, health problems and physical fitness are considerations in deciding if a person's blood pressure is normal. A general guide is given here, but you should check with your physician to decide if yours is safe or requires attention. The following two tables show what is generally considered normal and high levels of blood pressure. Many different health conditions and medications may affect what is normal for each person. This is more common in older persons.