The relationship between COVID-19 infection and blood pressure (BP) is not straightforward; the virus can cause both temporary drops and sustained elevations, often depending on the stage and severity of the illness. Since SARS-CoV-2 is a systemic virus, it affects many organs beyond the lungs, including the cardiovascular system responsible for regulating this pressure. Understanding how this infection influences BP requires separating the immediate effects during acute illness from the lingering effects that can occur weeks or months later.
Acute Hypotension During Infection
For some individuals experiencing a severe COVID-19 infection, blood pressure can drop significantly, a condition known as hypotension. This acute lowering is often a direct consequence of the body’s overwhelming inflammatory response. The immune system releases inflammatory molecules, sometimes called a cytokine surge, which causes widespread relaxation and widening of the blood vessels (vasodilation).
This dilation increases the capacity of the vascular system, causing pressure to fall dramatically, particularly in severe cases leading to septic shock. Furthermore, severe infection often involves substantial fluid loss due to high fever, vomiting, or reduced oral intake, leading to acute dehydration and depleted blood volume.
The virus also directly targets the cells lining the blood vessels, known as the vascular endothelium, through the ACE2 receptor. Damage to this lining impairs the vessels’ ability to contract properly, further contributing to a loss of vascular tone. Patients managing hypertension with medication may find their BP dropping into the hypotensive range, sometimes requiring a temporary adjustment or pause in their usual medication regimen under medical supervision.
Factors Leading to Elevated Blood Pressure
While acute infection can cause a drop in pressure, other individuals may experience the opposite effect, with blood pressure rising during or immediately following the illness. This temporary increase stems from the body’s general stress response. The physical strain of infection triggers the release of stress hormones like cortisol, which cause vasoconstriction and increase the heart rate, thereby raising blood pressure.
Certain medications commonly used to manage COVID-19 symptoms can also contribute to this elevation. Steroid treatments, such as dexamethasone, are known to increase blood pressure in some patients by affecting fluid and electrolyte balance. Furthermore, pre-existing hypertension, even if previously undiagnosed, can be exacerbated by the strain of the viral infection itself.
The stress of the pandemic environment, including social isolation and changes in activity, has been associated with a widespread rise in average blood pressure readings. This environmental stress, combined with the physiological stress of the illness, can lead to new or worsened hypertension. Studies show that even individuals with mild COVID-19 have a higher risk of developing new-onset high blood pressure in the months following infection.
Post-COVID Autonomic Dysfunction and BP Instability
For many individuals, blood pressure instability can linger long after the acute infection has passed, often as part of Long COVID. This persistence is frequently linked to autonomic dysfunction, where the body’s Autonomic Nervous System (ANS) is impaired. The ANS controls involuntary functions, including heart rate and blood pressure regulation.
When the ANS is damaged, blood pressure can become highly erratic or “labile,” leading to sudden drops or surges, particularly when changing position. One common manifestation is Postural Orthostatic Tachycardia Syndrome (POTS), where standing up causes the heart rate to accelerate rapidly, often accompanied by orthostatic hypotension (a dramatic drop in blood pressure).
These episodes of instability can cause symptoms such as lightheadedness, dizziness, fainting (syncope), or a racing heart. The underlying mechanism is thought to involve either the direct impact of the virus on the nervous system or an immune-mediated attack on ANS components.
When to Seek Medical Guidance
Monitoring blood pressure at home is an important first step, especially for anyone who has recovered from COVID-19. The most accurate readings are typically taken twice daily—once in the morning before medication or coffee, and again in the evening before bed. This consistent tracking provides healthcare providers with a comprehensive picture of your cardiovascular status.
Immediate medical attention is warranted if you experience warning signs related to low blood pressure, such as sudden, severe lightheadedness, dizziness upon standing, or fainting. A sustained systolic reading below 90 mmHg or a diastolic reading below 60 mmHg should also prompt a call to your doctor. Conversely, sustained readings above 130/80 mmHg, especially if new, should be discussed with a healthcare professional for potential treatment.
For milder symptoms of instability, simple measures like maintaining good hydration and increasing salt intake can help boost blood volume, but this should be discussed with a doctor first. If symptoms of dizziness, lightheadedness, or a rapid heart rate persist for weeks or months after the infection, seeking a referral to a cardiologist or a specialist familiar with autonomic dysfunction is recommended. These specialists can conduct specific tests to diagnose conditions like POTS and determine the most appropriate long-term management strategy.