High blood pressure, also known as hypertension, is a major risk factor for stroke. But what blood pressure levels put you at risk? Here, we’ll discuss the blood pressure ranges that can lead to stroke and steps you can take to reduce your risk.
Understanding Blood Pressure Readings
Blood pressure is recorded using two numbers, like 120/80 mmHg. The first number is your systolic pressure, which measures the pressure in your blood vessels when your heart beats. The second number is your diastolic pressure, which measures the pressure when your heart rests between beats.
According to the American Heart Association guidelines:
- Normal blood pressure is less than 120/80 mmHg
- Elevated blood pressure is 120-129/ under 80 mmHg
- Stage 1 hypertension is 130-139/80-89 mmHg
- Stage 2 hypertension is 140/90 mmHg or higher
The higher your blood pressure, the greater your risk of health problems like stroke. Here’s a look at the blood pressure levels that can lead to stroke.
Stage 1 Hypertension
If you have stage 1 hypertension with a systolic pressure of 130-139 mmHg or a diastolic pressure of 80-89 mmHg, your risk of stroke is doubled compared to those with normal blood pressure.
According to research, stage 1 hypertension accounts for nearly 25% of all stroke cases globally. Proper management of stage 1 hypertension could prevent nearly 40% of stroke cases.
Age and Stroke Risk
Your age also impacts your risk of stroke at different blood pressure levels. For example:
- If you’re 18-44 years old, stage 1 hypertension triples your stroke risk.
- If you’re 45-64 years old, stage 1 hypertension doubles your risk.
- After age 65, your stroke risk is 5 times higher with stage 1 hypertension.
The takeaway is that high blood pressure poses a greater stroke threat the younger you are when it develops. That’s why managing elevated or stage 1 hypertension early is critical.
Reducing Your Risk
If you have stage 1 hypertension, you may be able to lower your blood pressure through lifestyle changes like:
- Following a healthy diet like the DASH diet
- Reducing sodium intake
- Exercising regularly
- Losing weight if overweight
- Limiting alcohol
- Quitting smoking
- Trying stress-reduction techniques
Medications like diuretics, ACE inhibitors, ARBs, beta-blockers, and calcium channel blockers may also be used to treat stage 1 hypertension. With proper management, you may be able to lower your stroke risk.
Stage 2 Hypertension
Stage 2 hypertension occurs when your systolic blood pressure is 140 mmHg or higher or your diastolic blood pressure is 90 mmHg or higher. At this level, your risk of stroke increases dramatically.
Exact Risk Increase
Research shows that compared to people with normal blood pressure:
- Stage 2 hypertension triples your risk of ischemic stroke.
- Stage 2 hypertension increases your risk of hemorrhagic stroke up to 8 times.
In addition, the higher your blood pressure is above 140/90 mmHg, the greater your risk. For example, those with stage 2 hypertension of 150/95 mmHg have a much higher stroke risk than those at 140/90 mmHg.
Age Considerations
As with stage 1 hypertension, your age impacts your stroke risk at various stage 2 hypertension levels:
- If you’re age 18-44 with stage 2 hypertension, your stroke risk soars by 5-7 times.
- From age 45-64, stage 2 hypertension doubles your stroke risk.
- After age 65, your stroke risk is 9 times higher.
The takeaway is that aggressively treating stage 2 hypertension is critical, especially for younger adults.
Treatment
Stage 2 hypertension requires medication to lower your risk. Lifestyle changes can also help enhance the effects of medications. Options may include:
- ACE inhibitors or ARBs
- Diuretics or “water pills”
- Beta-blockers
- Calcium channel blockers
- Alpha-blockers
- Nervous system inhibitors
- Vasodilators
Work closely with your doctor to develop an effective treatment plan for your stage 2 hypertension.
Hypertensive Crisis
A hypertensive crisis occurs when your blood pressure shoots above 180/120 mmHg. A crisis requires emergency care to prevent organ damage and other serious health outcomes, including stroke.
Hypertensive crises come in two forms:
- Hypertensive urgency – when blood pressure is very high (180/120 mmHg or higher) but there is no organ damage.
- Hypertensive emergency – when dangerously high blood pressure (over 180/120 mmHg) is accompanied by organ damage such as stroke symptoms, chest pain, etc.
A hypertensive emergency is a medical emergency that requires rapid lowering of blood pressure. Seek immediate medical care if you experience stroke symptoms like weakness, numbness, vision changes, trouble speaking, or severe headache along with a hypertensive crisis.
Causes
Potential causes of a hypertensive crisis include:
- Missing high blood pressure medications
- Sudden withdrawal of blood pressure medications
- Illicit drug use, like cocaine or amphetamines
- Hormone disorders like hyperthyroidism or Cushing’s syndrome
- Pregnancy complications like preeclampsia
- Severe pain
- High stress
Those with chronic stage 2 hypertension are at increased risk of hypertensive crises, especially if medication is not taken as directed.
Emergency Treatment
During a hypertensive crisis, emergency measures will be taken to rapidly lower your blood pressure to prevent organ damage, stroke, and other threats to life. This may involve:
- IV antihypertensive medications
- Oxygen therapy
- Treating any underlying causes
Once stable, your blood pressure will continue to be monitored closely and brought to a safe level. Further treatment will focus on preventing future crises.
How Low BP Can Increase Stroke Risk
While high blood pressure is the most common contributor to stroke, very low blood pressure can also raise your risk in some cases. Here’s what the research shows:
Low BP in Older Adults
Orthostatic hypotension, a form of low blood pressure that occurs when moving from sitting to standing, is linked with higher stroke risk in adults over age 60. Studies show:
- Older adults with orthostatic hypotension had a 54% higher likelihood of stroke over 10 years compared to those without low blood pressure on standing.
- For adults over 75, the presence of orthostatic hypotension doubled stroke risk.
Possible reasons for this elevated stroke risk include cerebral hypoperfusion (reduced blood flow to the brain) and associated organ damage from low blood pressure episodes.
Low BP in Younger Adults
Research also shows that younger adults with low blood pressure tend to have higher long-term stroke risks. For example:
- One study found that adults under 50 with systolic blood pressure under 120 mmHg had a 67% higher stroke risk over 20 years compared to those with normal systolic pressure (120-129 mmHg).
- Another study found the stroke risk with low diastolic blood pressure under 70 mmHg was 52% higher in adults under 60.
Possible reasons for this relationship are uncertain. One theory is that underlying health conditions may simultaneously lower blood pressure while increasing stroke risk in younger people.
Should BP Be Raised?
While low blood pressure in younger and older adults correlates with higher stroke risk, there is insufficient evidence to recommend raising blood pressure as an intervention.
In older adults, non-drug strategies like increasing fluid and salt intake may help reduce symptoms of orthostatic hypotension and associated complications. But consult your doctor before making major dietary changes.
The key is to follow your doctor’s guidance regarding target blood pressure levels to optimize your cardiovascular health.
The Takeaway
Here are some key points on blood pressure levels that can impact stroke risk:
- Stage 1 hypertension (130-139/80-89 mmHg) doubles your risk of stroke compared to those with normal blood pressure.
- Stage 2 hypertension (140/90 mmHg and above) triples to up to 9 times your risk depending on age.
- Hypertensive crises over 180/120 mmHg require emergency care to prevent death or disability from stroke and other outcomes.
- Low blood pressure in older and younger adults also correlates with higher long-term stroke risk.
Work with your doctor to maintain blood pressure within a healthy range for your age and condition. This, along with managing other risk factors like smoking, can significantly lower your risk of devastating stroke.
| Blood Pressure Level | Category | Stroke Risk |
|---|---|---|
| Less than 120/80 mmHg | Normal | Average risk |
| 120-129/under 80 mmHg | Elevated | Slightly elevated risk |
| 130-139/80-89 mmHg | Stage 1 hypertension | 2 times higher risk |
| 140/90 mmHg or above | Stage 2 hypertension | 3 to 9 times higher risk |
| Over 180/120 mmHg | Hypertensive crisis | Extremely high risk – medical emergency |
References
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- Rapsomaniki E, Timmis A, George J, et al. Blood pressure and incidence of twelve cardiovascular diseases: lifetime risks, healthy life-years lost, and age-specific associations in 1·25 million people. Lancet. 2014;383(9932):1899-1911. doi:10.1016/S0140-6736(14)60685-1
- Appel LJ. The Effects of Dietary Factors on Blood Pressure. Cardiol Clin. 2017;35(2):197-212. doi:10.1016/j.ccl.2017.01.003
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- Giuseppe Mancia, Robert Fagard, Krzysztof Narkiewicz et al. 2013 ESH/ESC Guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). European Heart Journal. 2013;34(28):2159-2219. doi:10.1093/eurheartj/eht151