A blood pressure of 148/78 is high. Under current guidelines from the American Heart Association and American College of Cardiology, a systolic (top) number of 140 or higher places you in Stage 2 hypertension, the more serious of the two hypertension categories. Your diastolic (bottom) number of 78 is actually in the normal range, which makes this a specific pattern called isolated systolic hypertension.
Where 148/78 Falls on the Scale
Blood pressure is grouped into five categories. Normal is below 120/80. Elevated is 120 to 129 systolic with a diastolic still under 80. Stage 1 hypertension covers systolic readings of 130 to 139 or diastolic readings of 80 to 89. Stage 2 hypertension starts at 140 systolic or 90 diastolic. At 148, your top number puts you eight points into Stage 2 territory.
The key detail: when your systolic and diastolic numbers fall into different categories, the higher category is the one that applies. So even though 78 is technically normal on its own, the 148 drives the classification.
Why the Top Number Matters on Its Own
Having a high systolic reading paired with a normal diastolic reading is called isolated systolic hypertension. It’s especially common in people over 50, because arteries stiffen with age. Stiffer arteries don’t absorb the force of each heartbeat as well, which pushes the top number up while the bottom number stays put or even drops.
This pattern is not harmless just because the bottom number looks fine. Over time, isolated systolic hypertension raises the risk of stroke, heart disease, chronic kidney disease, and dementia. A large study of middle-aged and older adults found that people with systolic readings in the 140 to 159 range had a 31% higher risk of dying from coronary heart disease compared to those in the 120 to 139 range. The stroke risk was even steeper: for people under 60, readings in that same range were associated with more than double the risk of stroke death.
Confirm the Reading at Home
A single reading of 148/78 in a clinic doesn’t necessarily mean your blood pressure sits at that level all day. Some people experience what’s called white coat hypertension, where the stress of a medical visit temporarily pushes numbers up. The difference between clinic and home readings is considered significant if it exceeds 20 points systolic or 10 points diastolic.
To get a clearer picture, check your blood pressure at home using a validated upper-arm cuff. Sit quietly for five minutes first, keep your feet flat on the floor, and rest your arm on a table at chest height. Take two readings one minute apart, morning and evening, for at least a week. If your average home readings come in below 135/85, your in-office number may not reflect your true resting blood pressure. If home readings consistently stay in the 140s or above, the elevation is real and worth addressing.
What Typically Happens Next
For anyone with an average blood pressure at or above 140/90, current guidelines recommend both lifestyle changes and medication. The threshold for starting medication is lower (130/80) if you already have heart disease, diabetes, chronic kidney disease, a history of stroke, or a 10-year cardiovascular risk score of 7.5% or higher. At 148 systolic, most people will be offered medication regardless, because that reading is well past even the more conservative thresholds.
If you have diabetes or kidney disease, the target your provider will aim for is typically below 130/80, which means a reading of 148 is roughly 20 points above goal. For people with diabetes and signs of kidney damage, some specialists recommend starting treatment at any reading above 130/80.
How Much Lifestyle Changes Can Lower Your Numbers
Diet and exercise alone won’t always be enough at 148 systolic, but they can meaningfully close the gap. The DASH diet, which emphasizes fruits, vegetables, whole grains, and low-fat dairy while limiting sodium, has been shown to lower systolic blood pressure by an average of 11.5 points in people with hypertension. That alone could bring a reading of 148 close to the 130s.
Other changes that reliably lower blood pressure include reducing sodium to under 2,300 mg per day (ideally closer to 1,500 mg), losing weight if you carry extra pounds, getting at least 150 minutes of moderate exercise per week, limiting alcohol, and managing stress. Each of these contributes a few points of reduction on its own, and the effects stack. Combined with medication when needed, these habits are what bring blood pressure into a safe range and keep it there.
When a High Reading Needs Immediate Attention
A reading of 148/78 is not a medical emergency. The threshold for a hypertensive crisis is 180/120 or higher. At that level, or if you experience severe headache, blurred vision, chest pain, shortness of breath, or seizures alongside any elevated reading, call emergency services. At 148/78 without those symptoms, you have time to confirm the reading, schedule a visit with your provider, and start making changes.