The flu is a common respiratory illness caused by influenza viruses, typically leading to symptoms like fever, body aches, and fatigue. High blood pressure, or hypertension, is a widespread health condition characterized by elevated force of blood against artery walls. This article explores the connection between the flu and blood pressure, addressing how a flu infection can contribute to increased blood pressure readings.
The Flu’s Influence on Blood Pressure
While the flu does not generally cause long-term high blood pressure, it can lead to temporary elevations in blood pressure readings. The body’s immune response to a viral infection, such as the flu, involves widespread inflammation. This inflammation can affect blood vessel walls, causing them to narrow or become less flexible, which in turn increases resistance to blood flow and raises blood pressure.
When the body fights an infection, immune cells release signaling molecules called cytokines. These directly influence blood vessels by stimulating the release of peptides that constrict blood vessels. This vasoconstriction narrows arteries, increasing the resistance that blood encounters as it flows. Additionally, the inflammatory response can impact the renin-angiotensin-aldosterone system (RAAS), a hormonal system that regulates blood pressure, potentially leading to increased blood pressure. These changes are typically temporary and subside as the body recovers from the illness.
How Flu Symptoms and Treatments Affect Blood Pressure
Common flu symptoms can influence blood pressure. A fever, for instance, causes the heart to work harder to circulate blood and regulate body temperature, leading to a faster heart rate and potentially higher blood pressure. Pain and physical stress from the illness can also activate the sympathetic nervous system, which can temporarily elevate blood pressure. The body’s response to infection, including increased heart rate and inflammation, contributes to this temporary rise.
Dehydration, a frequent complication of the flu, can also impact blood pressure. When the body loses fluids, it can lead to a decrease in blood volume and an increased heart rate. This fluid loss can cause blood vessels to constrict and the body to retain salt, both of which can lead to a temporary rise in blood pressure.
Certain over-the-counter (OTC) cold and flu medications also play a role in blood pressure elevation. Decongestants, such as pseudoephedrine and phenylephrine, work by constricting blood vessels to reduce nasal swelling. This vasoconstriction, however, can also increase blood pressure throughout the body. Individuals with pre-existing high blood pressure should be cautious, as these medications can raise already elevated readings. Some liquid cold and flu medicines may also contain high levels of sodium, which can contribute to increased blood pressure.
Managing Blood Pressure During Flu Illness
Monitoring blood pressure during a flu infection is advisable, especially for individuals with pre-existing hypertension or other cardiovascular conditions. It is important to keep track of readings and note any significant or sustained elevations.
Self-care measures are important for managing both flu symptoms and blood pressure. Staying well-hydrated by drinking plenty of fluids helps to prevent dehydration. Getting ample rest allows the body to fight the infection. Over-the-counter pain relievers can help manage fever, body aches, and headaches, but individuals with hypertension should discuss the use of NSAIDs with their doctor.
Consulting a healthcare provider is recommended if blood pressure readings remain consistently high, if flu symptoms worsen, or if new concerning symptoms appear. Signs such as chest pain, difficulty breathing, severe headaches, or confusion warrant immediate medical attention, as these could indicate serious complications. Discussing medication choices with a doctor or pharmacist is important for those with hypertension, especially regarding decongestants or other medications that may interact with existing blood pressure treatments.