A systolic blood pressure of 148 mmHg is high. It falls into Stage 2 hypertension, the more serious of the two hypertension stages defined in the 2025 American Heart Association and American College of Cardiology guidelines. Stage 2 begins at 140 mmHg systolic or 90 mmHg diastolic, so a reading of 148 sits firmly in that range.
Where 148 Falls on the Blood Pressure Scale
Blood pressure is classified into four categories based on the top number (systolic) and bottom number (diastolic):
- 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 148, you’re 8 points above the Stage 2 threshold. That said, a single reading doesn’t confirm a diagnosis. Blood pressure fluctuates throughout the day, and factors like stress, caffeine, or a full bladder can temporarily push it higher. Your doctor will want to see elevated readings on multiple occasions before diagnosing hypertension.
Why This Number Matters for Your Health
Sustained blood pressure in this range carries real cardiovascular risk. A large study following nearly 350,000 men found that people with systolic readings between 140 and 159 had roughly 2.5 times the risk of dying from coronary heart disease compared to those with optimal blood pressure. The relationship between blood pressure and cardiovascular damage is continuous and graded: for adults aged 40 to 69, every 20-point increase in systolic pressure doubles the risk of stroke or death from heart disease.
The risks compound when other conditions are present. If you also have diabetes, high cholesterol, kidney disease, or existing heart disease, a systolic reading of 148 poses a greater threat than it would on its own.
If Only Your Top Number Is High
Some people have a high systolic number (the top one) while the diastolic number (bottom) stays below 80. This is called isolated systolic hypertension, and it’s the most common form of high blood pressure, particularly in people over 50. It typically results from stiffening of the arteries that happens with age, though conditions like an overactive thyroid, diabetes, heart valve problems, and obesity can also contribute.
A high top number on its own still raises your risk of stroke, heart disease, dementia, and chronic kidney disease over time. It’s not a “safer” type of hypertension. Treatment often involves the same lifestyle changes and medications used for other forms of high blood pressure, though doctors pay careful attention to making sure treatment doesn’t drop the bottom number too low.
Blood Pressure Targets by Age
For most adults, the current recommended target is below 130/80 mmHg, including those over 65. But guidelines vary somewhat for older and frailer patients. For people over 80, some guidelines set a more relaxed target of below 150 mmHg systolic, particularly when patients have functional limitations or are on multiple medications. European guidelines recommend starting treatment in people over 80 only when systolic pressure exceeds 160.
So while 148 is unambiguously high for a 45-year-old, an 85-year-old with limited mobility might have a different treatment goal. Functional status matters as much as age. For older adults in good physical health, the targets are generally the same as for younger people.
Make Sure Your Reading Is Accurate
Before worrying about a 148 reading, it’s worth confirming it was measured correctly. Small errors in technique can inflate your numbers by 10 to 15 points. The CDC recommends the following for an accurate reading:
- Timing: Don’t eat, drink, or exercise for 30 minutes beforehand. Empty your bladder first.
- Position: Sit with your back supported and both feet flat on the floor for at least 5 minutes before measuring. Don’t cross your legs.
- Arm placement: Rest your arm on a table at chest height. The cuff should go on bare skin, not over clothing.
- During the reading: Stay still and don’t talk.
- Repeat: Take at least two readings, one to two minutes apart, and average them.
If your reading is still around 148 after following these steps on multiple days, that’s a meaningful result worth acting on.
148 Is Not an Emergency
A systolic reading of 148 needs attention, but it is not a medical emergency. A hypertensive crisis, the level that requires immediate care, starts at 180/120 or higher. At that point, you should rest for a few minutes and recheck. If it stays at or above 180/120 and you experience chest pain, shortness of breath, blurred vision, or stroke symptoms like sudden numbness or weakness on one side of your body, call 911.
At 148, the concern is long-term damage rather than immediate danger. Persistently elevated blood pressure gradually strains your heart, damages blood vessel walls, and harms your kidneys over months and years. The good news is that bringing it down, whether through weight loss, exercise, dietary changes, reduced sodium intake, or medication, meaningfully reduces those risks. Even modest reductions make a difference: because risk doubles with every 20-point rise, bringing your systolic pressure down by 10 to 20 points translates into a substantial drop in your chances of stroke and heart disease.