A blood pressure reading of 135/98 mm Hg qualifies as Stage 2 hypertension under current guidelines, driven almost entirely by the diastolic (bottom) number. While the systolic value of 135 sits in a mildly elevated range, a diastolic reading of 98 crosses the 90 mm Hg threshold that clinicians treat as unambiguously high. This pattern, where the bottom number does most of the work, is common in younger and middle-aged adults and carries its own set of risks and causes worth understanding.
What the Two Numbers Mean at 135/98
Blood pressure is recorded as two values. The top number (systolic) reflects the force in your arteries when your heart contracts. The bottom number (diastolic) reflects the pressure between beats, when your heart is refilling. In a reading of 135/98, the systolic is only modestly above the 130 mm Hg cutoff that the American College of Cardiology now uses to define hypertension, but the diastolic is well into high territory. Under the widely adopted 2017 classification, any reading at or above 140 systolic or 90 diastolic counts as Stage 2 hypertension. Because the diastolic here is 98, that single number places the whole reading in the higher stage, even though the systolic number on its own would only land in Stage 1.
This matters because treatment decisions follow the higher category. A doctor seeing 135/98 would classify and manage it no differently than if both numbers were elevated. The reading also tells a physiological story: a diastolic pressure this high relative to the systolic suggests that the resistance in your smaller blood vessels is the main problem, rather than the overall volume of blood your heart is pumping per beat.
The Pattern Behind It: Isolated Diastolic Hypertension
When the diastolic is elevated but the systolic stays below 140, the clinical term is isolated diastolic hypertension, or IDH. A reading of 135/98 fits this description neatly. IDH is most commonly found in younger adults and tends to reflect increased resistance in the body’s smaller arteries, often driven by heightened activity of the sympathetic nervous system, the branch of your nervous system responsible for the fight-or-flight response.1Europe PMC. Isolated diastolic hypertension In other words, the blood vessels are squeezing tighter than they should be at rest, even though the heart itself may be pumping a normal amount of blood.
This pattern differs from what is typical in older adults, where stiff arteries cause the systolic number to climb while the diastolic stays the same or even drops. If you are under 50 and seeing readings like 135/98, the diastolic elevation is the defining feature, and it may represent an early stage of broader hypertension that will eventually push both numbers up. Some research has also suggested that in certain younger people, IDH turns out to be a relatively benign finding that resolves on its own, but the safest approach is to treat it as a signal worth investigating rather than a quirk to ignore.
Does a High Diastolic Actually Raise Your Risk?
For years there was a debate about whether diastolic pressure really mattered independently or was just a bystander alongside the systolic number. A large study using data from over 1.3 million adults settled this convincingly: both systolic and diastolic hypertension independently predicted heart attacks, strokes, and other cardiovascular events. Systolic elevation had the stronger effect, but diastolic hypertension on its own still raised the hazard of adverse outcomes.2PubMed. Effect of Systolic and Diastolic Blood Pressure on Cardiovascular Outcomes So the 98 in your reading is not something to brush off just because the 135 doesn’t look alarming.
Research in young adults paints a more specific picture. In a study following over 2.4 million people for a median of about 13 years, isolated diastolic hypertension at Stage 1 was associated with roughly a 32% increase in cardiovascular events compared to normal blood pressure. When both numbers were elevated, the risk climbed further.3PubMed. Cardiovascular Risk of Isolated Systolic or Diastolic Hypertension in Young Adults A reading of 135/98 sits right at the boundary where isolated diastolic hypertension starts to overlap with combined elevation, placing it in a range where cardiovascular risk is clearly real.
One exception worth noting involves kidney disease. In a study of people who already had chronic kidney disease, isolated diastolic hypertension was not associated with a higher rate of kidney decline, cardiovascular events, or death in that specific population.4PubMed Central. Isolated Diastolic Hypertension and Kidney and Cardiovascular Outcomes in CKD: The Chronic Renal Insufficiency Cohort (CRIC) Study Researchers are still working out why, but the takeaway is that IDH may behave differently depending on what other health conditions are present.
Could the Reading Be Wrong?
Before making any changes to your life or medications based on a single reading of 135/98, consider whether the measurement itself was reliable. Errors in blood pressure measurement are extremely common in clinical settings, and individual sources of inaccuracy can shift a reading by dramatic margins, as much as 33 mm Hg systolic or 23 mm Hg diastolic in either direction.5PubMed Central. Sources of inaccuracy in the measurement of adult patients’ resting blood pressure in clinical settings: a systematic review Everyday factors like a full bladder, crossing your legs, talking during the measurement, an unsupported arm, or a wrong-sized cuff can all push diastolic readings higher than they actually are.6PubMed Central. Strategies to reduce pitfalls in measuring blood pressure
This is why most guidelines recommend confirming high readings with multiple measurements on separate occasions, ideally including readings taken at home. If office readings consistently show high blood pressure but home or ambulatory readings are normal, the phenomenon is called white-coat hypertension, and it carries a much lower risk than true sustained hypertension. The reverse pattern, masked hypertension, where office readings look normal but out-of-office readings are elevated, carries risk nearly as high as having hypertension confirmed everywhere.7PubMed Central. Ambulatory Blood Pressure Monitoring to Diagnose and Manage Hypertension If your 135/98 reading was a surprise and you have no history of high blood pressure, tracking it at home over a week or two will tell you much more than a single office visit.
What Pushes Diastolic Pressure Up
The usual lifestyle suspects behind hypertension apply here: excess sodium, physical inactivity, excess weight, heavy alcohol use, and chronic stress. But a reading where the diastolic is disproportionately high can point toward some specific contributors.
Chronic psychological stress is one. A study comparing otherwise healthy people under sustained psychosocial stress to matched controls found that stressed subjects had diastolic pressures about 5 mm Hg higher, along with signs of altered autonomic regulation, including reduced sensitivity of the baroreflex, the body’s built-in mechanism for moment-to-moment blood pressure correction.8PubMed Central. Impact of chronic psychosocial stress on autonomic cardiovascular regulation in otherwise healthy subjects In practical terms, if your body is running in a low-grade stress mode around the clock, the blood vessels maintain higher resting tone than they should, and the diastolic number creeps up.
Sleep apnea is another commonly overlooked driver. Research has shown that in early-stage obstructive sleep apnea, diastolic blood pressure is often the first to rise, even before systolic pressure shows any change, and the increase was linked to higher body mass index.9Oxford Academic (American Journal of Hypertension). Diastolic blood pressure is the first to rise in association with early subclinical obstructive sleep apnea: lessons from periodic examination screening If you snore heavily, feel unrested in the morning, or have been told you stop breathing at night, a sleep study could uncover a treatable cause behind that elevated diastolic.
Dietary Changes That Move the Numbers
If 135/98 is confirmed, dietary changes are among the most effective first responses, and they can be remarkably powerful even without medication. The DASH diet (Dietary Approaches to Stop Hypertension) combined with sodium reduction has been studied in multiple clinical trials and can produce dramatic drops in blood pressure.10PubMed Central. DASH Diet: A Review of Its Scientifically Proven Hypertension Reduction and Health Benefits The diet emphasizes fruits, vegetables, whole grains, lean proteins, and low-fat dairy while limiting saturated fat, added sugars, and sodium.
The magnitude of the effect depends on where you start. In the landmark DASH-Sodium trial, combining the DASH diet with low sodium intake lowered systolic pressure by about 7 mm Hg in people without hypertension and by about 11.5 mm Hg in those who already had it, compared to a typical Western diet with high sodium.11PubMed. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet A later analysis breaking results down by baseline blood pressure found even more striking effects at the top end: people starting with the highest blood pressures saw systolic drops of roughly 21 mm Hg when switching from a high-sodium standard diet to the low-sodium DASH diet.12PubMed Central. Effects of Sodium Reduction and the DASH Diet in Relation to Baseline Blood Pressure Those are reductions that rival what a single blood pressure medication can achieve.
For someone at 135/98, this is encouraging. The systolic number doesn’t need to move much to reach a healthier range, and the diastolic, while higher, responds to the same interventions. Reducing sodium alone helps, but the combination of sodium reduction with the broader DASH eating pattern consistently produces larger effects than either strategy alone.
How Exercise Fits In
Regular physical activity is one of the most consistent blood pressure reducers in the research literature, and it has the advantage of lowering both numbers simultaneously. A large meta-analysis found that aerobic exercise lowered systolic pressure by about 3.5 mm Hg and diastolic by about 2.5 mm Hg on average.13PubMed Central. Exercise training for blood pressure: a systematic review and meta-analysis Another meta-analysis of randomized trials found similar reductions of about 4.7 systolic and 3.1 diastolic with aerobic training, and those reductions held regardless of exercise intensity or how many sessions per week people completed.14Journal of Human Hypertension. The effectiveness of exercise training in lowering blood pressure: a meta-analysis of randomised controlled trials of 4 weeks or longer
Those numbers represent averages across mixed populations of people with and without hypertension. Among people who actually have hypertension, the benefits are larger. One review found that endurance training lowered resting blood pressure by roughly 7/5 mm Hg in hypertensive groups, compared to about 2/2 mm Hg in people who started with normal readings.15PubMed. Exercise is good for your blood pressure: effects of endurance training and resistance training For someone at 135/98, that kind of reduction could meaningfully close the gap, bringing the diastolic from the high 90s into the mid- to low 90s, which combined with dietary changes could push it below 90 without necessarily needing medication.
Isometric resistance exercises, like wall sits and sustained handgrip squeezes, showed surprisingly large blood pressure reductions in one meta-analysis, but those findings are based on fewer studies and are not yet reflected in most clinical guidelines as a primary recommendation. Conventional aerobic activity like brisk walking, cycling, or swimming remains the best-supported starting point.
When Medication Becomes Part of the Conversation
Whether a reading of 135/98 warrants medication depends on more than the numbers alone. Treatment guidelines generally weigh a person’s overall cardiovascular risk, including factors like age, diabetes, cholesterol levels, smoking, and family history, alongside the blood pressure readings themselves.16Australian Prescriber. Drug treatment of elevated blood pressure A 30-year-old with no other risk factors and a confirmed 135/98 might be managed initially with lifestyle changes and follow-up monitoring. A 55-year-old with the same reading who also has diabetes or high cholesterol would likely be started on medication right away.
When medication is prescribed, the common first-line options include ACE inhibitors, calcium channel blockers, and thiazide diuretics. All of these have been shown to lower both systolic and diastolic pressure substantially. In a summary of trials, single-drug therapy with any of the major classes lowered systolic pressure by roughly 12 to 16 mm Hg and diastolic by roughly 8 to 12 mm Hg on average.17American Journal of Hypertension. A Summary of the Effects of Antihypertensive Medications on Measured Blood Pressure Angiotensin receptor blockers perform comparably and are often used when ACE inhibitors cause side effects like a persistent dry cough.18PubMed Central. Blood pressure reduction, persistence and costs in the evaluation of antihypertensive drug treatment–a review For a reading of 135/98, a single medication from any of these classes could plausibly bring both numbers into a healthy range.
The Long-Term Stakes for Your Brain
Most people associate high blood pressure with heart attacks and strokes, and rightly so. But elevated diastolic pressure in midlife also appears to affect cognitive health in ways that are slower and less visible. A study tracking adults from their 40s found that higher diastolic blood pressure at ages 40 to 44 was associated with significant declines in processing speed over the following 12 years. Higher diastolic pressure was also associated with a 13% increase in white matter lesions in the brain over eight years in the same age group, and a 31% increase in white matter lesions per 10 mm Hg of diastolic pressure in those aged 60 to 64.19Alzheimer’s & Dementia. Higher diastolic blood pressure aged 40‐44 is associated with declining cognition and increasing white matter lesions over 8‐12 year follow up
White matter lesions are areas of damage to the brain’s wiring that accumulate over time and are linked to cognitive decline and dementia risk. They tend to be caused by small-vessel damage, exactly the kind of vascular injury that sustained high diastolic pressure inflicts. For someone in their 30s or 40s seeing 135/98 on their blood pressure monitor, this research adds a layer of urgency that goes beyond the familiar heart-disease warnings. The damage is gradual and silent, making it easy to dismiss a reading that “doesn’t seem that bad” but that may be quietly affecting the brain over decades.
Pregnancy and Diastolic Pressure
A reading of 135/98 carries different weight during pregnancy. Elevated diastolic blood pressure from early to mid-pregnancy has been linked to a significantly higher risk of preeclampsia, a dangerous pregnancy complication involving high blood pressure and organ damage. In a large population-based study, women whose diastolic pressure remained elevated from early to mid-pregnancy had roughly 80% higher odds of developing preeclampsia compared to women whose diastolic dropped during the same period. The risk was even more pronounced when early-pregnancy hypertension and sustained diastolic elevation were combined, with the odds of preeclampsia rising more than threefold.20PubMed Central. Elevated diastolic blood pressure until mid-gestation is associated with preeclampsia and small-for-gestational-age birth: a population-based register study If you are pregnant or planning pregnancy and seeing diastolic readings in the high 90s, that warrants prompt discussion with your care provider rather than a wait-and-see approach.
When 135/98 Becomes Urgent
A single reading of 135/98 is not an emergency. Hypertensive emergencies are defined by severely elevated readings, typically above 180/120, accompanied by signs of organ damage like chest pain, shortness of breath, vision changes, or sudden confusion. The more common scenario is what’s sometimes called hypertensive urgency: very high numbers without symptoms. Even at readings above 180/110 found in an outpatient setting, a large retrospective study of nearly 60,000 patients found that sending people to the emergency department was not associated with better outcomes compared to adjusting medication and following up.21BMJ. Evaluation and management of hypertensive emergency
At 135/98, the situation is less dramatic but still demands attention. The reading is high enough to require confirmation, investigation of causes, and a management plan, but it is not the kind of reading that calls for a trip to the emergency room. The appropriate response is to confirm it with repeated measurements, schedule a medical evaluation, and begin the lifestyle changes described above. If you have symptoms like severe headache, chest tightness, or visual disturbances alongside any elevated reading, seek care immediately regardless of the specific numbers.