Signs of High Blood Pressure: What You Can Feel, What You Can’t, and When It Is an Emergency

Key Takeaways: Signs of High Blood Pressure

• In 2019, only 59% of women and 49% of men aged 30–79 with hypertension worldwide reported a previous diagnosis.[1]
• In my clinical experience, high blood pressure often causes no clear symptoms, and for some people the first sign has been the endpoint event itself, such as a heart attack or stroke.
• In an emergency department study, symptoms commonly blamed on high blood pressure were frequent among patients with raised readings, but apart from shortness of breath they were no more common at higher blood pressure stages.[2]
• In a general practice study, 51 of 102 hypertensive patients believed they could tell when their blood pressure was up; 86% of them could not predict it accurately.[3]
• Headache, often listed among the signs of high blood pressure, is a poor indicator. In 22,685 Norwegian adults, a systolic pressure of 150 mm Hg or higher was associated with a 30% lower risk of non-migrainous headache 11 years later.[4]
• In my experience, patients who report headache, a whooshing sound in the ears, pressure in the head or dizziness together with high readings have usually had fairly high blood pressure, although these symptoms alone do not show that blood pressure is the cause.
• Nosebleeds are associated with hypertension in pooled studies, but the association does not establish that high blood pressure causes them.[5][6]
• In 385 hypertensive emergencies, the most frequent presenting symptoms were focal neurological deficit, shortness of breath and chest pain.[7]
• The signs doctors rely on are measured: blood pressure readings, plus an ECG, kidney blood tests and a urine albumin test to look for organ damage.[9]
• In my experience, routine tests can give indirect clues: the ECG may show signs of left ventricular hypertrophy, and a urine sample may show protein.
• Athletes are not protected. Strength-trained athletes had higher blood pressure than endurance-trained athletes in a review of 138,390 athletes.[10]
• In my clinical experience, a reading taken at the doctor’s office is often raised by nerves; home readings over about a week, morning and evening, usually give a fairer picture.

Introduction: Why the Signs of High Blood Pressure Are So Easy to Miss

People search for the signs of high blood pressure expecting a list of symptoms to watch for. The research reviewed here gives a less comfortable answer: high blood pressure often causes no reliable symptoms, and many people with it have never been diagnosed. In a pooled analysis of 1201 population-representative studies, only 59% of women and 49% of men aged 30–79 with hypertension in 2019 reported that they had previously been diagnosed.[1]

I deal with patients who have high blood pressure every day, and a common problem is that it simply produces no clear signs or symptoms. Unfortunately, especially in the past, the first sign for some people could be the endpoint event itself, such as a heart attack or a stroke. In my emergency work, it is not unusual for an otherwise ordinary, previously healthy man to arrive and be diagnosed at the same time with coronary artery disease or a stroke, together with high cholesterol, hypertension and possibly diabetes. Some may wonder how this can happen. The usual explanation is that these conditions may cause no outward symptoms, or the patient does not notice them, until a major event brings them to light.

In my view, periodic health checks in Finland today give many people the chance to have these conditions detected before it comes to that. In my view, however, healthcare still has blind spots, and this can still happen in Finland too. If a person has no occupational health care, or it is not active, or they are, for example, self-employed and have not noticed anything wrong themselves, these conditions may never be tested for.

As a physician and former competitive athlete, I look at this question from two sides: what general medicine knows about hypertension symptoms, and what applies to people who train hard. This article covers which commonly cited signs of high blood pressure hold up in research, which symptoms point to an emergency, which signs doctors actually look for, and what is specific to athletes.

Are There Any Reliable Signs of High Blood Pressure?

Many symptoms are popularly treated as signs of high blood pressure: headache, dizziness, blurred vision, nosebleeds, chest pain and shortness of breath.[2] An emergency department study tested whether these symptoms actually track blood pressure. Over 14 days, 551 of 1908 adult patients (29%) had blood pressure that stayed at 140 mm Hg systolic or 90 mm Hg diastolic or above on a repeat measurement.[2] In 26% of the 529 patients with complete data, the chief complaint included at least one of these symptoms.[2] Apart from shortness of breath, which was more common at the highest blood pressure stage, none of the symptoms differed significantly between blood pressure stages.[2] When a subset of patients was interviewed, most reported at least one such symptom, again with no relationship to blood pressure stage.[2]

The authors concluded that these symptoms are common among patients with raised blood pressure but appear unrelated to how high the blood pressure is.[2] The study was done in a single urban emergency department with a predominantly African American population, so the findings may not apply to every setting.[2]

Feeling your own blood pressure turns out to be unreliable too, which makes self-perceived signs of high blood pressure hard to trust. In a general practice study, 102 hypertensive patients attended weekly blood pressure checks and were asked beforehand whether they thought their pressure was higher, lower or the same as usual.[3] Half of them (51) believed they could tell when their blood pressure was up, but 86% of these “predictors” could not predict it accurately, and their actual blood pressure and its variability did not differ from those of the other patients.[3] The predictors were significantly more anxious and reported more symptoms.[3] The authors recommended that doctors advise patients not to use their own subjective assessment of blood pressure to guide how they take their medication.[3]

In my clinical experience, many patients have some idea of their own blood pressure, and some have a monitor at home, although not everyone knows the reference values. For many, it comes as a surprise that their blood pressure is raised at the appointment, and they ask how they could have known. The honest answer is that high blood pressure rarely causes symptoms, and measuring it is the only reliable way to find out.

Headache: The Most Commonly Assumed Sign of High Blood Pressure

Headache is often mentioned among the signs of high blood pressure. Long-term population data point the other way. In a Norwegian prospective study, 22,685 adults who were unlikely to have headache at baseline had their blood pressure measured in 1984–86 and answered a headache questionnaire 11 years later.[4] Those with a systolic pressure of 150 mm Hg or higher had a 30% lower risk of non-migrainous headache at follow-up (risk ratio 0.7, 95% CI 0.6–0.8) than those with a systolic pressure below 140 mm Hg.[4] The risk of non-migrainous headache also fell as diastolic pressure rose, in both sexes, and the findings were not influenced by antihypertensive medication; for migraine, there was no clear association.[4] The authors proposed hypertension-associated hypalgesia, a reduced pain sensitivity that probably involves the baroreflex system, as one possible explanation.[4]

Very high readings are a different situation. In an emergency department cohort of 670 patients with acute severe hypertension, headache was a presenting symptom in 18.6% of patients without organ damage (hypertensive urgencies) but in only 2.6% of those with organ damage (hypertensive emergencies).[7] In this cohort, headache was therefore more frequent in the group without acute organ damage, but this finding cannot be used to rule out organ damage in an individual patient.

There is, however, a group of patients who report symptoms together with markedly raised readings, and I see them at my practice at regular intervals. They usually complain of headache, and may also notice a pulsing or whooshing sound in the ears, a feeling of pressure in the head, dizziness or sometimes a sensation in the chest. Many then measure their blood pressure at home, find it high and are understandably frightened. In my experience, patients who report symptoms like these together with high readings have usually had fairly high blood pressure, although the symptoms alone do not show that blood pressure is their cause.

Nosebleeds and Dizziness: Associated, but Not Proof

Nosebleeds are another of the classic signs of high blood pressure. A 2017 meta-analysis of 10 studies found a significantly higher risk of nosebleeds (epistaxis) in people with hypertension, with an odds ratio of 1.532 (95% CI 1.181–1.986).[5] Heterogeneity between the studies was considerable (I² = 49.3%), and the authors noted that this association does not support a cause-and-effect relationship between hypertension and nosebleeds.[5]

An earlier systematic review of nine studies found that six reported higher blood pressure at the time of the nosebleed than in a control group or the general population.[6] The reviewers pointed out that a high reading during a nosebleed cannot establish causation, because stress and a possible white-coat effect may raise it, but that it may lead to a first diagnosis of hypertension that was already present.[6]

Dizziness behaves similarly. In the emergency department study, dizziness was the chief complaint of 2% of patients at every blood pressure stage.[2] In the 670-patient cohort, it was reported by 17.5% of patients with hypertensive urgencies and 8.6% of those with hypertensive emergencies.[7]

When High Blood Pressure Is an Emergency

The 2025 American Heart Association/American College of Cardiology guideline defines severe hypertension in non-pregnant adults as blood pressure above 180/120 mm Hg, and states that without evidence of acute target-organ damage it should be evaluated and treated in the outpatient setting.[8] A very high number alone, then, is not automatically an emergency. The older term hypertensive urgency, used in the study below, corresponds broadly to what the guideline now calls severe hypertension without acute target-organ damage.[8]

What turns very high blood pressure into an emergency is acute damage to organs. In the 670-patient emergency department cohort, patients with organ damage were classified as hypertensive emergencies (385 patients) and those without as hypertensive urgencies (285 patients).[7] Among the emergencies, the most frequent presenting symptoms were focal neurological deficit (36.3%), shortness of breath (29.3%) and chest pain (13.5%).[7] Of the patients with hypertensive emergencies, 98% were hospitalised, compared with 23.2% of those with urgencies, and hospital mortality was 12.5% versus 1.8%.[7]

In that cohort, focal neurological deficits, shortness of breath and chest pain were more common in emergencies, whereas headache and dizziness were more common in urgencies.[7] From a clinical perspective, new neurological symptoms, chest pain or marked shortness of breath warrant immediate emergency assessment, particularly together with a very high reading, rather than repeated measuring at home. At the same time, the emergency department study is a reminder that the same symptoms are common and non-specific, so their presence alone does not show that blood pressure is the cause.[2]

In my emergency work, patients fairly often arrive with dizziness and other preceding symptoms, and their systolic pressure turns out to be around 200 mm Hg and the diastolic above 100 mm Hg. Some have untreated hypertension, some have treated hypertension that is poorly controlled, and for some it is a completely new finding. How they are managed depends above all on whether there are signs of acute organ damage. In my experience, when appropriate assessment shows no signs of acute organ damage and the pressure comes down after initial treatment, care can often continue as an outpatient with oral treatment and follow-up. Sometimes, however, a hypertensive crisis needs a stay on a ward, with monitoring, until the pressure has come down to a suitable level and the patient can be safely discharged.

As an emergency physician, when there are no signs of acute organ damage, I generally prefer oral blood pressure medication to bring the pressure down. A hypertensive emergency with organ damage is a different situation, in which treatment and monitoring take place in hospital and depend on the organ involved. In selected patients, an intramuscular drug such as clonidine (Catapresan) has sometimes been needed instead, although this is not a routine approach for severe hypertension without acute organ damage; in my experience, these patients usually also need hospital-level monitoring to make sure their blood pressure stays stable.

The Signs of High Blood Pressure Doctors Look For

Because symptoms are unreliable, the practical signs of high blood pressure are measured ones. The 2025 American guideline classifies blood pressure as follows:[8]

Category	Systolic (mm Hg)		Diastolic (mm Hg)
Normal	below 120	and	below 80
Elevated	120–129	and	below 80
Stage 1 hypertension	130–139	or	80–89
Stage 2 hypertension	140 or higher	or	90 or higher

How these categories compare with the European and Finnish thresholds, and how to measure blood pressure correctly, is covered in what is normal blood pressure.

The second group of signs is found on tests rather than felt. Long-standing high blood pressure can damage the heart, arteries, eyes, brain and kidneys, collectively called hypertension-mediated organ damage, and the review reports that its presence is associated with a 2- to 3-fold increased risk of later cardiovascular disease.[9] A 2026 expert review compared the 2024 European Society of Cardiology, 2023 European Society of Hypertension, 2025 American and 2020 International Society of Hypertension guidelines.[9] It concluded that a basic assessment for heart and kidney damage is recommended in all patients, using an electrocardiogram (ECG), serum creatinine with estimated glomerular filtration rate (eGFR), and the albumin-to-creatinine ratio in a morning spot urine sample.[9] More advanced tests depend on the initial findings, with echocardiography as the preferred first advanced test.[9]

From a clinical perspective, high blood pressure cannot really be measured directly with laboratory tests, but routine examinations can sometimes give indirect clues. In my experience, the ECG may show changes that can raise a clinician’s suspicion of chronic high blood pressure, such as signs of left ventricular hypertrophy or a strain pattern, although these findings are not specific to hypertension. A chest X-ray may sometimes show a widened heart shadow, but this is not a specific finding; an echocardiogram shows the heart’s structure much more precisely. In my view, the thickening of an athlete’s heart can differ from that caused by long-standing high blood pressure, although telling the two apart requires an echocardiogram and an assessment of the clinical context. A urine sample may sometimes show protein, which can be a sign of kidney damage, although protein in the urine can also have other causes.

Signs of High Blood Pressure in Athletes

When it comes to signs of high blood pressure, training does not make an athlete immune. A systematic review of 51 studies covering 138,390 athletes, mostly aged 18–40, found no significant overall difference in blood pressure between athletes and non-athlete controls.[10] Strength-trained athletes had higher blood pressure than endurance-trained athletes (131.3/77.3 vs 118.6/71.8 mm Hg), and reported hypertension prevalence ranged from 0% to 83%.[10] Measurement methods were poorly standardised, and only eight studies reported whether an appropriate cuff size had been used.[10] Three of four studies that related blood pressure to left ventricular hypertrophy found a significant positive linear association, although the authors noted that confounding factors may have played a role.[10]

Another measured sign is the blood pressure response during an exercise test. A systematic review and meta-analysis that identified 12 longitudinal studies with 46,314 people without significant coronary artery disease, followed for a mean of 15.2 years, found that a hypertensive response at moderate exercise intensity carried a 36% greater rate of cardiovascular events and mortality, after adjustment for age, office blood pressure and cardiovascular risk factors.[11] Each 10 mm Hg increase in systolic pressure at moderate intensity was associated with a 4% increase in events and mortality, whereas systolic pressure at maximal workload was not significantly associated with the outcome.[11] The population was people undergoing clinical exercise stress testing, so the findings may not transfer directly to trained athletes. Athlete-specific data on exercise blood pressure and masked hypertension are covered in what is normal blood pressure.

How High Blood Pressure Is Actually Found

Taken together, the evidence leaves one dependable sign of high blood pressure: a measured reading, confirmed by repeated measurements. The studies reviewed here suggest that headache, nosebleeds and dizziness do not reliably indicate the level, and the sense of “knowing” when blood pressure is up was wrong for most patients who believed they had it.[3] The effects of long-standing high blood pressure on the heart and kidneys are looked for with tests, including an ECG, kidney blood tests and a urine albumin test.[9] The main exception is markedly raised blood pressure with signs or symptoms suggesting acute organ damage, which warrants immediate emergency assessment; a hypertensive emergency is diagnosed when acute organ damage is present.[7]

In my practice, I often suggest that patients get a blood pressure monitor for home use, so that readings can also be taken outside the clinic. Blood pressure measured at a doctor’s appointment, including at mine, is often raised because patients are nervous, a phenomenon often called the white-coat effect, and when a clinic reading deviates in some direction, in my experience it is nearly always upward. A single clinic reading may therefore not give a fair picture of the situation. In these situations, I usually ask patients to take a series of home readings for about a week, or at least a few days, in the morning and evening, with several readings per session if needed: if the first readings are affected by nerves, in my experience the following ones often give a more representative picture. In my experience, the average over several days at home then gives a much better basis for judging whether blood pressure is genuinely raised.

For what the evidence shows on salt, diet, weight, alcohol and exercise, and on measuring at home to see whether changes are working, see how to lower blood pressure.

Conclusion: Signs of High Blood Pressure

For most people, there are no reliable signs of high blood pressure. In 2019, only 59% of women and 49% of men aged 30–79 with hypertension worldwide reported a previous diagnosis.[1] Symptoms often blamed on blood pressure were common in patients with raised readings but, apart from shortness of breath, did not track the level, and 86% of patients who believed they could tell when their blood pressure was up could not predict it accurately.[2][3] Over 11 years of follow-up, higher systolic pressure was associated with a lower, not higher, risk of non-migrainous headache.[4]

Symptoms that may suggest organ damage, such as new neurological symptoms, breathlessness and chest pain, warrant urgent assessment, especially with a very high reading, and severe symptoms like these need assessment whatever the reading. Everything else is found by measuring: repeated blood pressure readings, and tests of the heart and kidneys once hypertension is confirmed. In athletes, regular training alone does not rule out high blood pressure.[10]

In my clinical experience, the first sign can still be a heart attack or a stroke in people who fall outside periodic health checks, for example those without active occupational health care. Many patients are surprised to find their blood pressure raised at an appointment, and a single clinic reading is often pushed up by nerves. In my practice, home readings taken morning and evening over about a week have given a much fairer picture, and they are the way I usually confirm whether blood pressure is genuinely raised.

References

1. https://doi.org/10.1016/S0140-6736(21)01330-1
2. https://doi.org/10.1016/j.ajem.2004.02.043
3. https://doi.org/10.1038/sj.jhh.1000432
4. https://doi.org/10.1136/jnnp.72.4.463
5. https://doi.org/10.1177/0194599817721445
6. https://doi.org/10.1007/s00405-013-2450-z
7. https://doi.org/10.1111/jch.13083
8. https://doi.org/10.1161/HYP.0000000000000249
9. https://doi.org/10.1093/eurjpc/zwag052
10. https://doi.org/10.1136/bjsports-2014-093976
11. https://doi.org/10.1093/ajh/hps053