Feb. 15, 2023 -- If you're recovering from COVID-19 or you're a long COVID patient, you may have been advised by your doctor to monitor yourself for high blood pressure. This is because research has shown that COVID can raise both systolic and diastolic blood pressure and can cause high blood pressure even if you've never had it. But those recovering from the virus should be aware of a lesser-known concern as well: low blood pressure post-COVID.
Italian researchers found that some patients who already have high blood pressure and who have either recovered from COVID or have post-COVID symptoms can experience a sudden drop in blood pressure, or BP. These patients are at immediate risk for acute kidney injury, which is when your kidneys suddenly stop working properly. Anyone can experience low blood pressure post-COVID, but according to Mayo Clinic data, women are more likely to develop it than men are. Researchers from the Czech Republic also found that older, frail post-COVID patients who have high blood pressure can develop low blood pressure, possibly because their BP medication suddenly becomes too strong for their bodies.
While it's worth remaining diligent with your health following an infection with the virus, it's important to not fret over the possibility of low blood pressure after COVID.
“Most causes of low blood pressure do not involve having had COVID-19,” says Emily Lau, MD, MPH, a cardiologist at Massachusetts General Hospital in Boston and an instructor in medicine at Harvard University.
What Are the Symptoms of Low Blood Pressure?
Low blood pressure is a reading below 90 over 60. If your blood pressure drops under those numbers, the American Heart Association says that you may experience symptoms such as:
- Feeling tired
- Blurry vision
- Feeling thirsty
- Rapid breathing
- Skin that feels cold and clammy
- Feeling depressed
What Is the Link Between COVID and Low Blood Pressure?
Doctors are still learning about how COVID affects our bodies, so there are a number of possibilities.
“One of the primary challenges in dealing with long COVID is that a specific symptom or syndrome is only the tip of the iceberg,” says Austin Chan, MD, assistant professor of medicine at Morehouse School of Medicine in Atlanta, GA. “Each patient can have a different biological mechanism that results in a similar symptom. Maintaining your blood pressure is the result of multiple different neurologic and endocrine systems working in concert. The problem could come from any one of these sources.”
And how COVID “behaves” in the body is another factor that may explain the connection.
“Whether the acute phase of COVID is related to direct viral impact on the body or causes changes in the balance of organs is something we're still trying to understand,” explains Lau. “We are still figuring the virus out, but we see that it seems to have a predilection for certain organ systems in the body.”
One potential cause of low blood pressure due to COVID is autonomic dysfunction. This problem happens when your autonomic nervous system, which controls functions in your body such as your blood pressure, heart rate, body temperature, and digestion, becomes unbalanced. Research has suggested that COVID impacts the autonomic nervous system's immune response, and that can cause conditions like orthostatic hypotension – a drop in blood pressure when you stand up from sitting or lying down.
The COVID virus itself can also cause your blood pressure to drop due to fever and infection. That drop in BP can put stress on your heart, and if you have COVID-related breathing issues, an increased need for oxygen can worsen heart damage, according to data from Harvard Medical School. Low blood pressure that occurs with shortness of breath and a fast heart rate can also be a sign of COVID pneumonia.
When Should You Take Your Blood Pressure at Home?
It's not necessary to take your BP too frequently.
“I think it's about balance,” says Lau. “I don't want my patients taking their blood pressure 10 times a day. There's no reason to stress yourself out like that because it's normal that your blood pressure changes often.”
But if your doctor thinks checking your blood pressure at home is a good idea, do it the right way, or typically just once a day.
“Maintain a log to share with your primary care [doctor],” says Chan. And be prepared that you may see a range of results.
“Long-haul COVID may only result in low blood pressure at certain times, so readings taken at rest or sitting may only offer part of the picture,” Chan says. Regular checkups with your doctor can provide a fuller picture of any medical issues tied to low pressure that you may have.
Treatment for low blood pressure can include taking a new medication or adjusting the medications you already take, wearing compression stockings, getting up from sitting or lying down in a new way, or simply drinking more fluids.
When Is Low Blood Pressure a Medical Emergency?
It's uncommon for low blood pressure to be life-threatening. But it's important to go to the emergency room if you get a severely low reading with low BP symptoms. This is because you need enough blood to get to your organs so they have the oxygen they need. A reading that is not severely low but does connect to symptoms should not be ignored, either.
“If you experience a blood pressure change along with lightheadedness, feeling unsteady, or passing out, definitely tell your doctor,” says Lau.
Focusing on taking good care of yourself as you get over COVID, or navigate long COVID, is always your best bet. This means not only following your doctor's advice about your blood pressure, but eating well, sleeping enough, and reducing stress.
“Recovering from COVID is an incredibly challenging time for many people,” says Chan.
Knowing this can give you a sense of control over your health and help you feel better both physically and emotionally.