A good blood pressure reading is 120/80 millimeters of mercury or below. The range for a normal blood pressure reading could be slightly lower in children and teenagers, explains Mayo Clinic.
A person with a normal blood pressure reading can maintain it by checking it frequently and living a healthy lifestyle. Blood pressure readings change regularly depending on the body's activity, and correct results can be obtained by checking pressures on different occasions. There are no symptoms of a good or a bad blood pressure, and a doctor can confirm blood pressure levels through routine testing, explains Better Health Channel.