The word hypertension means high blood pressure, a condition that typically develops over several years and increases risk of heart disease, stroke, and kidney disease. It is quite common in the U.S., affecting one in three adults according to the American Heart Association.
As the heart pumps blood throughout the body, the blood flow meets resistance against the walls of the arteries (the vessels that carry oxygen-rich blood from the heart to the cells, tissues, and organs). It is the measurement of this resistance force that is referred to as blood pressure. As the heart pumps larger amounts of blood, and the arteries get more narrow, blood pressure creeps higher.
The tricky thing about hypertension is that there can be no symptoms whatsoever. Often it is found only during routine checkups (experts recommend getting your blood pressure measured at each physician visit starting at age 18).
The top number of a blood pressure reading is called systolic and the bottom number is called diastolic. When a reading is lower than 120/80 mm Hg (120 over 80 millimeters of mercury) most of the time, this is considered healthy.
We say “most of the time” because blood pressure varies according to the time of day, and also shifts with exercise and changes in stress, sleep, and even posture. Before being diagnosed with hypertension, your physician will measure your blood pressure several times over a period of time in order to get an accurate reading.
Either the top number, the bottom number, or both numbers of a blood pressure reading can become too high.
Hypertension (high blood pressure) is diagnosed when the systolic (top number) is between 140 and 159, and the diastolic (bottom number) is between 90 and 99 most of the time.
When levels are between these two blood pressure regions, so that the reading is higher than 120/80, but still lower than 140/90, this is considered prehypertension. People in this category have a higher chance of developing hypertension.
Factors that can lead to high blood pressure include heavy drinking (more than one drink daily for women, more than two daily for men), too much stress, too much salt in your diet (more than 2,300 mg a day for healthy people, more than 1,500 mg a day for people with hypertension or diabetes), smoking, being inactive, or overweight, or having a family history.