What You Need To Know About Isolated Systolic Hypertension

Elevated blood pressure is common in older adults. The most common variant of hypertension is when the first number in your reading is high, but the second is normal. This is called isolated systolic hypertension. So, what do you need to know about this health condition, and who is at risk?

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What is isolated systolic hypertension?

Systolic pressure is your blood pressure when the heart is actively pumping and is the first number in a blood pressure reading. The second number in the reading is diastolic pressure, which is your blood pressure between beats when your heart relaxes.

In isolated systolic hypertension (ISH), your first number is over 130 millimeters of mercury (mm Hg), but your second number is still under 80 mm Hg (i.e., normal). One of the main causes is the stiffening of your major arteries, which is a natural part of aging. It can also be associated with obesity, valvular heart problems, an overactive thyroid, or diabetes. About 30%¹of people aged 60 and older have untreated ISH. It is more common in women and non-Hispanic Black people.

Isolated systolic hypertension can sometimes occur in younger people.

How is isolated systolic hypertension diagnosed?

Isolated systolic hypertension is typically asymptomatic to start with. However, it can cause damage to organs that create symptoms as it progresses. Usually, like other forms of high blood pressure, doctors diagnose ISH through routine screening using a blood pressure monitor. It's vital to have your blood pressure checked regularly, especially as you get older

Untreated isolated systolic hypertension can lead to symptoms including:

  • Headaches

  • Blurred vision

  • Unsteadiness

  • Shortness of breath

  • Confusion

  • Palpitations

Your doctor will not diagnose you with ISH based on a single high reading. Typically, they will take multiple readings to establish whether your systolic pressure is consistently high. Your doctor may use home monitoring to track how your blood pressure changes throughout the day and to ensure it’s not spiking because of anxiety.

Can isolated systolic hypertension cause heart disease and stroke?

Untreated isolated systolic hypertension can increase your risk² of heart disease or stroke. This is particularly true if your systolic blood pressure is 160 mm Hg or higher. The evidence is less strong at lower levels, so your doctor may weigh up the benefits against the side effects and other risk factors when deciding whether to use medication.

According to one study,³ treatment of systolic hypertension led to a 42% decrease in risk of stroke and a 30% decrease in risk of cardiovascular disease. The same study showed a 50% reduction in dementia. Treating your blood pressure can significantly extend your lifespan and improve your quality of life.

Who is at greater risk for isolated systolic hypertension?

Risk factors for isolated systolic hypertension include:

  • Age

  • Being assigned female at birth

  • Being Black or African-American

  • Eating a high sodium diet (which most of us do)

  • Smoking

  • Physical inactivity

  • Obesity

  • Alcohol abuse

  • Genetics and family history

Most isolated systolic hypertension cases are "primary," meaning that another medical condition doesn’t cause them. Rarely, other diseases can cause it, such as diabetes, anemia, narrowing of the arteries in the kidneys, or other forms of chronic kidney disease.  If you have these conditions, you will need to monitor your blood pressure more closely for “secondary” ISH.

If you are at high risk, you may want to check your blood pressure more often. If you detect ISH early, lifestyle factors can often mitigate it without needing medication.

What lifestyle changes are helpful?

Typically, doctors will recommend the same lifestyle changes that are beneficial for hypertension in general, which include:

Avoiding or reducing alcohol consumption 

Drink no more than two drinks a day for men, one for women. Do not drink if you are on medication that might interact with alcohol.

Eating a diet low in sodium and high in potassium

You should limit sodium intake to less than 1.5g per day. You should use spices and salt substitutes rather than adding table salt to meals. Most people in the U.S. get too much sodium just from processed food.

Exercising regularly

This can be a challenge for older people with mobility issues, and working with a physical therapist is helpful. However, moderate walking is more than sufficient to positively affect blood pressure. Always talk to your doctor before starting an exercise program.

Managing stress

Stress and anger are well known to increase blood pressure.

Quitting smoking or vaping

Both smoking and vaping increase blood pressure. 

Doing your best to achieve and maintain a good weight

Even a small amount of weight loss can reduce your blood pressure and provide many other health benefits.

The Dietary Approaches to Stop Hypertension (DASH) diet is a great approach for most people to reduce high blood pressure. Some people may find their blood pressure goes down on a vegetarian or vegan diet. However, a plant-based diet is not necessarily healthy, and unhealthy plant-based diets⁴ containing lots of refined grains may raise systolic blood pressure. Ideally, talk to a dietician who can help you develop a healthy diet that is sustainable for you.

The goal is to lower your blood pressure without needing medication. Lifestyle changes alone are sometimes enough to control hypertension, and medication is necessary only if lifestyle changes aren’t sufficient or if the person cannot comply. (For example, somebody with significant mobility issues may be unable to exercise enough).

You have to sustain any changes for them to be effective. If your doctor tells you to change your diet and lifestyle, you need to keep it up for the foreseeable future. Many of these changes are helpful even in healthy people, such as quitting smoking, managing stress, and staying active.

Medication for isolated systolic hypertension

If you have unusually high ISH or if lifestyle changes are not enough to reduce your blood pressure, you may be prescribed medication.

A specific concern with ISH is that the diastolic blood pressure is generally normal or may even be below normal. The loss of elasticity in your arteries with age also causes a lowering of diastolic blood pressure. Low diastolic blood pressure can cause fatigue, blurred vision, dizziness, and frequent falls.

The diastolic phase is when your heart gets its blood flow replenished. If your diastolic blood pressure is too low, it can lead to heart muscle damage called ischemia, which may eventually cause heart failure.

A slightly different regimen is needed to avoid diastolic blood pressure falling too low. The following medications typically treat isolated systolic hypertension:

Thiazide diuretics

Thiazide-like diuretics are generally the first go-to medication for hypertension, particularly chlorthalidone. Lower doses are preferable, and doctors are more likely to add another drug than change the dose. Chlorthalidone seems to perform better at treating heart failure than similar drugs. However, it can cause hypokalemia (low potassium), which your diet or a potassium-sparing diuretic can correct.

For extremely elderly patients (80+) or patients with a stroke history, doctors commonly prescribe Indapamide.

Calcium channel blockers (CCB)

Calcium channel blockers (also known as calcium channel antagonists), such as nitrendipine, block calcium from entering the cells of the heart and arteries, weakening the contraction of the arteries and letting them relax and open.

These drugs have a powerful impact on cardiovascular disease in older adults with systolic hypertension. One study showed that nitrendipine, either alone or combined with a diuretic, reduced stroke by 42% and cardiovascular endpoints by 26%.

Other CCBs include amlodipine and nifedipine. They generally have few side effects, which tend to be minor. Dihydropyridine⁵-type CCB side effects can include:

  • Headaches

  • Lightheadedness

  • Flushing

  • Leg swelling

Diuretics and calcium channel blockers can be the first medication you take, but doctors often prescribe them together.

Angiotensin-converting enzyme (ACE) inhibitors

ACE inhibitors treat hypertension in general and certain types of heart failure. Doctors often prescribe ACE inhibitors to patients who also have type 2 diabetes or chronic kidney disease. ACE inhibitors can improve kidney outcomes.

However, ACE inhibitors have been shown not to perform as well in Black people and are generally not prescribed in this population. Instead, a thiazide diuretic or CCB is better.

ACE inhibitors can help with your high blood pressure and associated conditions. It inhibits an enzyme in the body from producing angiotensin II, a substance that narrows blood vessels, thus reducing your blood pressure. Common side effects include:

  • A dry cough, which generally goes away after a few months

  • Dizziness

  • Hypotension (blood pressure going too low)

  • Fainting

  • Hyperkalemia (low levels of potassium)

Your doctor might prescribe any of these medications, depending on your age, other conditions you might have, and whether you have allergies. Beta-blockers commonly treat other forms of hypertension, but they are not as effective against isolated systolic hypertension. Generally, they are not a first-line medication, but they may sometimes be part of combination therapy. Many people need more than one medication to reduce their blood pressure.

In older people with marginal systolic hypertension, doctors may choose not to treat with medication due to the increased risk of low blood pressure that can lead to falls. The benefits of treatment have to outweigh the risks, and doctors will always recommend lifestyle changes.

Can isolated systolic hypertension be cured?

There is no cure for ISH, but you can manage it with lifestyle changes and medication. Typically, if your doctor puts you on medication for any form of high blood pressure, you will stay on it for life. In some cases, lifestyle changes can bring your blood pressure down to the point where medication is no longer required, or your doctor can decrease your dosage.

What if your diastolic pressure is very low?

You might have very high systolic blood pressure but low, normal, or subnormal diastolic pressure (less than 70mm Hg). This is a challenge because the high systolic pressure is an indication for treatment, and the low diastolic pressure is a contraindication. However, elevated systolic pressure causes the worst health outcomes.

Some doctors may choose not to treat the high systolic blood pressure, especially if diastolic pressure is below 60mm Hg.⁶ Treatment may cause diastolic blood pressure to go too low. Patients can technically have hypertension and hypotension simultaneously. Significant low blood pressure can increase ischemic cardiac events. This is due to heart disease caused by the heart not getting enough blood.

In the case of low diastolic pressure, any intervention to lower systolic pressure will reduce both, resulting in worse outcomes. Your doctor will weigh up various factors, including your age, whether you have coronary artery disease, and whether you are already experiencing drops in blood pressure (one symptom is dizziness or fainting when standing up). You might want to seek a second opinion before deciding whether to go ahead with medication.

The lowdown

Isolated systolic hypertension is the most common form of high blood pressure in people over 65. It’s caused by age-related hardening of the arteries, and it’s more common in women, Black people, and people with a family history of this type of high blood pressure.

Lifestyle changes are the first course of action, followed by medication if they’re ineffective. First-line medications are thiazide diuretics or calcium channel blockers. In some cases, doctors may choose not to treat ISH due to the risk of sending diastolic blood pressure too low, which can also cause significant health problems and heart disease.

However, most people with ISH benefit from treatment to reduce the increased risk of stroke, dementia, and heart disease that comes with the condition. In any case, increasing exercise, reducing sodium intake, and maintaining a healthy weight can improve overall health in all adults.

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