117 mmHg
42 mmHg
Only the diastolic value (42 mmHg) is below normal. The systolic value (117 mmHg) remains at or above 90 mmHg. This pattern defines Isolated Diastolic Hypotension.
What is isolated diastolic hypotension?
Isolated diastolic hypotension (IDH) is a blood pressure pattern in which diastolic pressure falls below 60 mmHg while systolic pressure remains at or above 100 mmHg.
A reading of 117/42 mmHg falls into this category when the diastolic number is below 60 mmHg.
IDH differs from general hypotension, where both systolic and diastolic pressure are low, and from isolated systolic hypertension, where only systolic pressure is elevated.
The primary driver of IDH in older adults is age-related arterial stiffening, which causes the aorta and large arteries to lose elasticity, raising systolic pressure while diastolic pressure declines.
Approximately 14% of community-dwelling adults aged 65 and older meet the criteria for IDH, according to data from the Cardiovascular Health Study (Guichard et al., Hypertension, 2011).
A 2023 NHANES-based study published in the Journal of Clinical Hypertension (Wang et al.) found that DBP below 60 mmHg was associated with a 30% higher risk of all-cause mortality (HR 1.30, 95% CI 1.12–1.51) and a 34% higher risk of cardiovascular death (HR 1.34) compared to individuals with DBP between 70 and 80 mmHg, even when systolic pressure was within normal range.
The same study found that antihypertensive medication use increased the odds of DBP falling below 60 mmHg by 52% (OR 1.52, 95% CI 1.26–1.83), identifying overtreatment as a leading correctable cause in adults already receiving blood pressure therapy.
What are the symptoms of isolated diastolic hypotension?
Isolated diastolic hypotension may not always produce noticeable symptoms, particularly when the diastolic pressure is only mildly reduced and develops gradually.
Symptoms arise when diastolic pressure drops low enough to reduce coronary perfusion and blood flow to the brain during cardiac relaxation.
Dizziness or lightheadedness
Especially upon standing quickly, reflecting reduced cerebral perfusion during the diastolic phase.
Fatigue
Resulting from reduced oxygen delivery to tissues when cardiac output during diastole is insufficient.
Blurred vision
Occurring when diastolic blood pressure falls low enough to reduce retinal perfusion.
Difficulty concentrating
Arising from insufficient blood flow to the brain affecting cognitive function.
Palpitations
Reflecting the heart’s compensatory response to inadequate diastolic filling pressure.
Shortness of breath
Particularly during physical exertion, when increased cardiac demand cannot be met by a compromised diastolic pressure.
Cold, clammy skin
Indicating peripheral vasoconstriction as the body compensates for reduced central perfusion.
Fainting or syncope
In more severe cases, when cerebral blood flow drops below the threshold required to maintain consciousness.
Symptoms vary among individuals and overlap with many other conditions, which makes IDH challenging to diagnose based on symptoms alone.
Confirmation requires consistent diastolic readings below 60 mmHg paired with systolic pressure at or above 100 mmHg across multiple measurements.
What are the causes of isolated diastolic hypotension?
Isolated diastolic hypotension develops when diastolic pressure falls disproportionately compared to systolic pressure, most commonly through one of the following mechanisms.
Identifying the primary cause determines which intervention is appropriate, since IDH from overtreatment requires medication adjustment rather than the lifestyle changes used for age-related arterial stiffening.
What do MAP and Pulse Pressure tell you at 117/42 mmHg?
Mean arterial pressure (MAP) and pulse pressure (PP) provide additional clinical context beyond the systolic and diastolic numbers alone.
MAP is calculated as (Systolic + 2 x Diastolic) / 3 and represents the average driving pressure that perfuses vital organs throughout the cardiac cycle.
Normal MAP falls between 70 and 100 mmHg.
A reading of 117/42 mmHg produces a MAP that the calculator above displays.
In IDH, MAP may remain within or near the normal range because systolic pressure is not elevated, but the low diastolic component still signals inadequate coronary perfusion pressure during cardiac relaxation.
For a full explanation of MAP thresholds and their clinical implications, see the mean arterial pressure guide.
Pulse pressure (PP) is the difference between systolic and diastolic pressure and reflects arterial stiffness and stroke volume.
Normal PP falls between 40 and 60 mmHg.
A PP above 60 mmHg is classified as widened and is the defining characteristic of IDH, directly reflecting the same arterial stiffening mechanism that drives the diastolic number down while systolic stays high.
Widened pulse pressure in IDH is associated with increased cardiovascular risk independent of the absolute blood pressure values, and serves as a clinical marker for the severity of underlying vascular aging.
For a full breakdown of pulse pressure values and their significance, see the pulse pressure guide.
What to do when your blood pressure is 117/42 mmHg
A confirmed IDH reading at 117/42 mmHg requires clinical evaluation to identify the underlying cause before any treatment is initiated.
How do you confirm an IDH reading?
A single reading at 117/42 mmHg does not confirm IDH.
Diagnosis requires diastolic pressure consistently below 60 mmHg with systolic at or above 100 mmHg across multiple measurements taken on separate occasions, at rest, and with a validated upper-arm cuff.
Home monitoring over 7 to 14 days, with two readings morning and evening, provides the most reliable pattern for clinician evaluation.
For a step-by-step guide on correct home blood pressure measurement, cuff positioning, and timing protocol, see the how to take blood pressure guide.
What immediate steps should you take?
Seek medical evaluation within the week when diastolic pressure reads below 60 mmHg and symptoms such as dizziness, fatigue, or near-fainting are present.
Seek emergency care immediately when diastolic pressure reads below 60 mmHg and any of the following are present: chest pain, confusion, loss of consciousness, or shortness of breath at rest.
Do not adjust or stop blood pressure medication independently to raise diastolic pressure, as abrupt medication changes can cause rebound hypertension.
What happens if isolated diastolic hypotension is left untreated?
Untreated IDH produces progressive cardiovascular and organ damage through two primary mechanisms: reduced coronary perfusion during cardiac diastole, and impaired cerebral blood flow from chronically insufficient diastolic pressure.
Regular monitoring, identification of the underlying cause, and appropriate intervention reduce each of these risks measurably.
How do you treat isolated diastolic hypotension?
Treatment of IDH depends on the underlying cause and focuses on raising diastolic pressure without producing systolic over-correction or orthostatic side effects.
Adjusting medications
Medication review is the first step when IDH follows the initiation or dose increase of antihypertensive therapy.
Alpha-blockers, diuretics, and nitrates lower diastolic pressure more than systolic pressure and are the most common pharmacological drivers of IDH.
A clinician may reduce the dose, switch to a drug class with less diastolic lowering effect, or adjust the dosing schedule to prevent trough-level diastolic drops.
For a full overview of how blood pressure medications affect systolic and diastolic pressure differently, see the blood pressure medications guide.
Lifestyle modifications
Lifestyle interventions support IDH management by stabilizing blood volume, improving vascular tone, and reducing orthostatic episodes.
For a complete blood pressure eating plan with dietary strategies applicable to IDH management, see the blood pressure diet guide.
Prescription treatments for persistent IDH
Pharmacological treatment is reserved for symptomatic IDH that persists despite lifestyle modification and medication review.
An alpha-1 agonist that constricts blood vessels and raises blood pressure when standing. Midodrine reduces dizziness and fainting episodes in orthostatic IDH and is taken in doses timed around periods of upright activity.
A synthetic mineralocorticoid that increases sodium and fluid retention, raising blood volume and blood pressure. Fludrocortisone is typically used for IDH driven by autonomic dysfunction or adrenal insufficiency.
Both medications require close monitoring for side effects including hypertension rebound, fluid retention, and electrolyte imbalances, and are not appropriate for all patients.
Monitoring blood pressure at home
Regular home monitoring tracks the effectiveness of treatment and detects further diastolic drops before symptoms develop.
Use a validated upper-arm blood pressure monitor twice daily, in the morning before medication and in the evening, and record both systolic and diastolic values.
Share weekly averages with your clinician at each follow-up to allow timely dose adjustments.
For guidance on measurement technique and monitor selection, see the how to take blood pressure guide.
Frequently Asked Questions about isolated diastolic hypotension
Is isolated diastolic hypotension dangerous if my systolic pressure is normal?
A diastolic pressure below 60 mmHg with normal systolic pressure is associated with measurably higher cardiovascular risk.
A 2023 NHANES-based study (Wang et al., Journal of Clinical Hypertension) found that DBP below 60 mmHg was associated with a 30% higher risk of all-cause death and a 34% higher risk of cardiovascular death compared to DBP between 70 and 80 mmHg, even when systolic pressure was within normal range.
The Cardiovascular Health Study found IDH to be an independent risk factor for incident heart failure over a 12-year follow-up in community-dwelling adults aged 65 and older (Guichard et al., Hypertension, 2011).
What causes isolated diastolic hypotension in otherwise healthy adults?
Age-related arterial stiffening is the most common cause in adults over 60, producing high systolic and low diastolic pressure simultaneously as the aorta loses elasticity.
Overtreatment with antihypertensive medications, particularly alpha-blockers, is the leading correctable cause in adults already receiving blood pressure therapy.
Dehydration and rapid weight loss are additional reversible causes that warrant fluid and dietary assessment before pharmacological intervention is considered.
Can exercise make isolated diastolic hypotension worse?
Moderate, well-planned aerobic exercise improves cardiovascular health and vascular tone, supporting diastolic pressure over time.
Vigorous exercise combined with dehydration can temporarily worsen diastolic drops, particularly in older adults and those on diuretics.
Start with gentle activity, maintain adequate hydration before and during exercise, and avoid prolonged upright posture without movement during recovery periods.
Should I increase my salt intake to raise low diastolic pressure?
A modest increase in dietary sodium can help raise diastolic pressure by increasing blood volume, but only under medical supervision.
Salt intake increases are contraindicated in patients with heart failure, chronic kidney disease, or uncontrolled systolic hypertension, where the risks of increased sodium outweigh any diastolic benefit.
Is 117/42 mmHg a cause for concern?
A reading of 117/42 mmHg warrants evaluation when the diastolic number falls below 60 mmHg, particularly when symptoms such as dizziness, fatigue, or near-fainting are present.
Consistent readings below this threshold require clinical assessment to identify the underlying cause and determine whether intervention is needed.
Can isolated diastolic hypotension be reversed?
Medication-induced IDH is frequently reversible through dose reduction or drug substitution under clinician supervision.
Dehydration-related IDH resolves with adequate fluid and sodium intake.
Age-related arterial stiffening is not reversible, but its cardiovascular consequences can be managed through lifestyle modifications, careful medication titration to avoid excessive diastolic lowering, and regular monitoring.
For context on the broader spectrum of low blood pressure conditions and their management, see the hypotension guide.