A blood pressure of 118/78 is a good reading. It falls squarely in the “normal” category, which the American Heart Association defines as below 120/80 mmHg. You’re just under both thresholds, meaning your heart is pumping blood through your arteries at a healthy level of force.
Where 118/78 Fits in the Categories
Current guidelines, updated in 2017 by the American Heart Association and the American College of Cardiology, sort blood pressure into distinct ranges. These categories apply to all adults regardless of age:
- Normal: below 120 systolic and below 80 diastolic
- Elevated: 120 to 129 systolic and below 80 diastolic
- Stage 1 hypertension: 130 to 139 systolic or 80 to 89 diastolic
- Stage 2 hypertension: 140 or higher systolic or 90 or higher diastolic
At 118/78, both your numbers are in the normal range. You’re 12 points below the Stage 1 hypertension threshold for the top number and 2 points below it for the bottom number. That said, your diastolic reading (78) is close to the 80 cutoff, so it’s worth keeping an eye on over time.
What the Two Numbers Mean
The top number (118) is your systolic pressure. It measures the force your blood exerts against artery walls when your heart contracts and pushes blood out. The bottom number (78) is your diastolic pressure, which measures that same force between beats, when your heart is relaxing and refilling with blood. Both numbers matter, though systolic pressure becomes a more important predictor of heart disease risk after age 50 because arteries stiffen and accumulate plaque over time.
There’s also a useful calculation hiding in your reading. Subtracting the bottom number from the top gives you your pulse pressure: 118 minus 78 equals 40 mmHg. A normal pulse pressure is right around 40, so yours is textbook. Pulse pressure that’s consistently too wide (above 60) or too narrow can signal problems with heart valve function or blood vessel stiffness.
One Reading Isn’t the Full Picture
Blood pressure is not a fixed number. It rises and falls throughout the day following a predictable rhythm. It typically starts climbing a few hours before you wake up, peaks around midday, and drops in the late afternoon and evening. During sleep, it’s usually at its lowest. Exercise, caffeine, stress, and even a full bladder can push it higher in the moment.
There’s also a well-known phenomenon called white coat hypertension, where blood pressure spikes simply from being in a medical setting. The reverse can happen too: some people have normal readings at the doctor’s office but elevated pressure the rest of the day. This is why a single reading of 118/78 is reassuring but not definitive. A pattern of readings over days or weeks gives a much more reliable picture of your cardiovascular health.
Getting an Accurate Reading at Home
If you’re checking your blood pressure at home, small details in how you sit and prepare can shift the numbers by several points in either direction. The CDC recommends a specific routine: avoid eating, drinking, smoking, alcohol, caffeine, and exercise for at least 30 minutes before measuring. Empty your bladder. Then sit in a comfortable chair with your back supported for at least five minutes before taking the reading.
When you’re ready, keep both feet flat on the floor with legs uncrossed. Rest the arm wearing the cuff on a table so it sits at chest height. The cuff should go directly against bare skin, not over a sleeve. Don’t talk while the reading is in progress. Crossing your legs or letting your arm hang at your side instead of resting it on a surface can artificially raise your numbers.
Keeping Your Blood Pressure in This Range
A normal reading today doesn’t guarantee a normal reading in five or ten years. Blood pressure tends to creep upward with age as arteries lose flexibility. The habits that keep it in check are straightforward but require consistency.
Aim for at least 30 minutes of moderate physical activity every day. This could be brisk walking, cycling, swimming, or anything that gets your heart rate up without leaving you gasping. Adding strength training at least two days a week provides additional benefit. On the dietary side, sodium is the biggest lever. The general limit is 2,300 milligrams per day (roughly one teaspoon of table salt), but for most adults, staying under 1,500 milligrams is ideal. That means paying attention to packaged and restaurant foods, which account for the majority of sodium in most people’s diets.
Maintaining a healthy weight, limiting alcohol, managing stress, and getting enough sleep all play supporting roles. None of these are dramatic interventions. They’re the same habits that protect against heart disease, stroke, and diabetes more broadly. For someone already at 118/78, the goal isn’t to fix a problem. It’s to keep the numbers from drifting into elevated or hypertensive territory as the years pass.