RELATED: 40 Subtle Signs Your Body Is Telling You Something’s Seriously Wrong. The CDC warns that “high blood pressure is called the ‘silent killer’ because it usually has no warning signs or symptoms, and many people do not know they have it.” The agency reports that high blood pressure was a primary or contributing cause of death for nearly half a million people in the U.S. in 2018. While your blood pressure rises and falls naturally throughout the day, when it’s consistently elevated, your risk increases for heart disease, heart attack, and stroke. According to a 2015 study published in the journal Medicine, approximately 54 percent of strokes and 47 percent of coronary heart diseases around the world are attributable to high blood pressure.ae0fcc31ae342fd3a1346ebb1f342fcb High blood pressure is considered such a widespread and pressing burden on health systems around the world that, of the World Health Organization’s (WHO) nine key voluntary targets to improve public health, one is to “reduce global prevalence of raised blood pressure by 25 percent between 2010 and 2025.” RELATED: If You Have This in Your Blood, You’re 42 Percent More Likely to Have a Heart Attack. Without symptoms, there’s only one way to know if your blood pressure levels are healthy, high, or low. “Measuring your blood pressure is the only way to know,” the CDC says. Blood pressure is the level at which your blood is pushing out against the walls of your arteries as it travels around your body. When your blood pressure is measured, it gives a reading of two numbers. The first is your systolic pressure, which is the level of pressure recorded when your heart beats. The second is your dystolic pressure, which is the measurement taken when your heart is resting in between those beats. So the full reading of your blood pressure would be presented as one number over another—for example, “120 over 80” or “120/80 mm Hg”. The United Kingdom’s National Health Service (NHS) advises that healthy blood pressure numbers should be within a range of readings: at the low end 90/60 mm Hg, and at the high end 120/80 mm Hg. Anything below or above those readings would be considered low or high respectively. The CDC notes some healthcare professionals set the figures slightly higher at 130/80 or 140/90. “Low blood pressure is less common,” the NHS points out. “Some medicines can cause low blood pressure as a side effect. It can also be caused by a number of underlying conditions, including heart failure and dehydration.” RELATED: For more up-to-date information, sign up for our daily newsletter. “It is well documented that lifestyle changes can lower blood pressure as much as pills can, and sometimes even more,” says Naomi Fisher, MD, director of hypertension service and hypertension innovation at the Brigham and Women’s Hospital Division of Endocrinology, Diabetes, and Hypertension, and associate professor of medicine at Harvard Medical School writing on Harvard Health’s site. She advises that maintaining a healthy weight is by far the most effective way of reducing high blood pressure (or preventing it from occurring). Other dietary advice includes reducing your salt intake and limiting alcohol to one drink per day. Additional effective methods of blood pressure reduction include regularly doing both movement-based and weightlifting-based exercise, and using daily meditation or breathing exercises to reduce the stress hormones that constrict your blood vessels. If you smoke, ditching that habit can also reduce your blood pressure. By applying these methods, you can hopefully bring your blood pressure down to a safe level—or, better yet, prevent it from spiking in the first place. RELATED: This Is The Single Best Way to Predict Your Heart Attack Risk, Experts Say.