What You Need To Know About High Blood Pressure When You’re Sick

High blood pressure (hypertension) affects 47% of adults in the US¹. The condition carries many risks, including heart disease, heart attack, and stroke, some of the leading causes of death.

Many people are unaware of their high blood pressure; it can go unnoticed as symptoms are generally uncommon, except when high blood pressure is very severe. Your doctor will probably ask to check your blood pressure every time you have an appointment — this is common practice and a good opportunity to catch undiagnosed hypertension or underlying health conditions.

There are many different causes of high blood pressure, including being overweight, smoking, not doing enough exercise and several underlying health conditions like kidney disease and diabetes. You can also get high blood pressure when you have an illness, like an infection or the flu.

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Can you get high blood pressure when you’re sick?

Illnesses can cause high blood pressure, especially if you have a fever. Other viral or bacterial infections like bronchitis, strep throat, and pneumonia can cause your heart rate to spike and your blood pressure to rise.

Your blood pressure might rise when you’re ill for these reasons:

  • Your body temperature has increased

  • Your heart rate has increased

  • Your body’s immune system is responding to an infection

  • Inflammation

Some medications taken to treat illnesses and health conditions can also cause high blood pressure.

Can sickness cause low blood pressure?

Low blood pressure (hypotension) when you’re sick is usually caused by dehydration. When you are vomiting or have a fever or diarrhea, your body can become dehydrated and your blood pressure may drop.

A serious illness or infection like septicemia (a condition where infection enters the bloodstream) can also cause low blood pressure.

Can medications cause high blood pressure?

Some of the ingredients found in medication can cause high blood pressure.


Decongestants can cause high blood pressure as they shrink blood vessels in the body. You might be taking them to treat the symptoms of migraines and headaches.

Be aware of the following popular over-the-counter decongestants if you have high blood pressure:

  1. Phenylephrine

  2. Oxymetazoline

  3. Pseudoephedrine (Sudafed)

Medications containing salt

Consuming too much salt² is a leading cause of high blood pressure, but some medications have high salt content. Always speak to your doctor before taking any new medication if you are at risk of high blood pressure or have been diagnosed to check whether the ingredients are safe for you.

Can underlying health conditions cause high blood pressure?

Your blood pressure might rise when you’re sick because you have an underlying health condition — this is called secondary hypertension.

Health conditions that cause high blood pressure include:

  • Diabetes

  • Kidney disease

  • Underactive or overactive thyroid

  • Cushing’s syndrome

  • Lupus

  • Obstructive sleep apnea

Pregnancy can also cause hypertension.

Always discuss ongoing symptoms with your doctor to rule out or diagnose an underlying health condition. High blood pressure could be a symptom of an undiagnosed condition that requires treatment.

How to manage high blood pressure

You can follow these general lifestyle strategies to help manage high blood pressure when you’re sick and avoid serious complications.

Eat a balanced diet

Consuming a heart-healthy diet³ can help keep your blood pressure in check while you’re ill. The American Heart Association (AHA) recommends consuming these foods:

  • Fruits (avoid sugar-sweetened fruit drinks)

  • Deeply colored leafy vegetables (like broccoli, carrots, and spinach)

  • Fatty fish (like salmon and mackerel)

  • Eggs

  • Soy products (like tofu)

  • Lean meats

  • Whole grains (like brown rice and whole-wheat bread)

  • Nuts, seeds, and legumes

  • Low-fat or fat-free cheese, yogurt, and milk

Limit processed and packaged foods

When you’re ill and have no energy to cook a healthy meal, it’s tempting to consume processed snacks and packaged meals. The problem with these is that they usually contain a lot of salt which can exacerbate high blood pressure.

The majority of people’s salt intake in the US⁴ comes from processed and packaged food. The salt is added during the production process to add flavor and aid preservation. To reduce your salt intake, try to eat as much fresh, homemade food as possible instead of buying pre-packaged meals and snacks.

Limit meals out and takeaways

The food you eat at restaurants or buy as takeout generally contains a lot of salt. To lower your salt intake and maintain healthy blood pressure, cook at home as much as possible and limit those Friday night takeaways.

Minimize alcohol consumption

Research⁵ shows that consuming alcohol can increase blood pressure, so you should try to limit your alcohol intake to reduce your risk of high blood pressure when you’re sick.

AHA⁴ recommends restricting yourself to two drinks a day if you are male and one drink a day if you are female. However, it might be best to avoid alcohol completely if you are unwell to aid your recovery and prevent further complications, including high blood pressure.

Reduce caffeine consumption

AHA⁶ recommends consuming caffeine in moderation as part of a balanced and healthy diet. How caffeine impacts blood pressure is unclear, but as a stimulant that can lead to difficulty sleeping, it might be best to avoid or limit caffeine while you’re unwell to help you get enough rest.

Manage your stress

Your stress levels can rise when you feel unwell, especially if your illness is impacting your ability to carry out everyday tasks, work, or enjoy time with loved ones. Stress may exacerbate high blood pressure, particularly if you respond to stress by consuming unhealthy food, smoking, or drinking alcohol.

There are lots of methods that can help lower stress levels, and you may find that some help eases the symptoms of your illness. You could try meditation, yoga, deep breathing, and gentle exercise. Doing things that you enjoy or practicing self-care may help decrease stress, like getting a relaxing massage or doing your favorite activity.

When to see a doctor about high blood pressure when you’re sick

Although high blood pressure is generally symptom-free, severe cases can cause symptoms.

Symptoms of severe high blood pressure are rare but may include:

  • Headaches

  • Difficulty breathing

  • Nosebleeds

If you experience any of these symptoms, seek medical help right away.

The lowdown

Illness can trigger or worsen high blood pressure because of the medication you are taking, your body’s response to your illness, or an underlying health condition. High blood pressure can put you at risk of serious complications.

You can take steps to maintain healthy blood pressure and improve your overall health, including consuming a healthy diet, reducing your salt, alcohol, and caffeine intake, and managing stress. Always ask for a blood pressure check when you see your doctor and get advice before taking new medications. If you experience symptoms of severe high blood pressure, get medical help right away.

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