A blood pressure of 118/88 is not ideal. While the top number (118) falls in the normal range, the bottom number (88) crosses into Stage 1 hypertension territory. Under current guidelines, any diastolic reading between 80 and 89 qualifies as Stage 1 high blood pressure, even when the systolic number looks fine.
Why the Bottom Number Matters
Blood pressure readings have two components. The top number (systolic) measures pressure when your heart beats, and the bottom number (diastolic) measures pressure between beats. A reading is classified by whichever number falls into the higher category. So even though 118 is perfectly healthy on its own, the 88 pushes the overall reading into the high blood pressure range.
This pattern has a name: isolated diastolic hypertension. It means only the bottom number is elevated while the top stays below 130. About 6 in 100 people in the U.S. have this condition, and roughly 1 in 5 adults diagnosed with high blood pressure fall into this category. It tends to be more common in younger adults.
How Much Risk Does 88 Diastolic Carry?
The risk depends significantly on your age. In younger adults (ages 20 to 39), Stage 1 isolated diastolic hypertension is associated with about a 32% higher risk of cardiovascular events compared to people with fully normal readings. That’s a meaningful bump, especially over decades of exposure.
In middle-aged and older adults, the picture is different. A large study of adults with an average age of 55 found no statistically significant increase in cardiovascular risk from isolated diastolic hypertension. This likely reflects the fact that as arteries stiffen with age, systolic pressure becomes the more important predictor of heart problems while diastolic pressure naturally trends downward.
So if you’re younger, a consistent diastolic reading of 88 deserves attention. If you’re older, the top number is generally more relevant to your long-term health.
Make Sure the Reading Is Accurate
A single reading of 118/88 doesn’t necessarily mean your blood pressure stays at that level. Blood pressure fluctuates throughout the day based on stress, caffeine, physical activity, and even how you’re sitting. Before drawing conclusions, it’s worth confirming the number with proper technique.
The CDC recommends sitting in a comfortable chair with your back supported for at least five minutes before measuring. Keep both feet flat on the floor with legs uncrossed, and rest your arm on a table at chest height. Don’t eat, drink, or talk during the reading. The cuff should sit against bare skin, not over a sleeve. Take at least two readings one to two minutes apart and average them. If you emptied your bladder beforehand and followed these steps, you can trust the result more than a rushed reading at a pharmacy kiosk.
Lifestyle Changes That Lower Diastolic Pressure
For a diastolic reading in the 80 to 89 range, lifestyle changes are typically the first and most effective approach. Medication usually isn’t necessary at this level unless you have other cardiovascular risk factors.
The most impactful changes target sodium, exercise, and weight:
- Sodium: Keep intake below 2,300 mg per day. For most adults, aiming for 1,500 mg or less is ideal. That means reading labels carefully, since most excess sodium comes from processed and restaurant foods rather than the salt shaker.
- Exercise: At least 30 minutes of moderate physical activity every day, plus strength training at least two days a week. Walking, cycling, and swimming all count. Consistency matters more than intensity.
- Weight: Even a modest reduction in body weight can lower both numbers. The relationship between weight and blood pressure is nearly linear, so every few pounds lost tends to help.
Alcohol, stress, and sleep quality also play roles. Cutting back on alcohol, finding reliable ways to manage stress, and getting consistent sleep can each shave a few points off your readings. These changes work together, and combining several of them often produces results comparable to a single blood pressure medication.
What to Do With This Reading
A reading of 118/88 is not a crisis. For reference, a hypertensive emergency starts at 180/120 or higher. But it’s also not a number to ignore, particularly if you’re under 40 or if repeated measurements confirm the pattern. Track your blood pressure at home over a week or two, following proper measurement technique each time. If your diastolic consistently lands at 80 or above, that’s a reliable signal to start making changes and to mention it at your next medical visit.
High blood pressure rarely causes noticeable symptoms until it has already done damage. The fact that you’re checking your numbers and asking questions puts you ahead of most people.