Yes, an infection can cause a temporary rise in your blood pressure (BP) as your body mounts a defense against invading pathogens. Blood pressure is the measure of the force of blood pushing against the walls of your arteries as the heart pumps it. During an illness, the body activates complex systems designed to fight the infection, and a temporary elevation in BP is often an unintended consequence. While this spike is usually short-lived and resolves once the infection is cleared, it requires attention, particularly for individuals who already have a history of hypertension.
Mechanisms Behind Acute Blood Pressure Elevation
The temporary increase in blood pressure during an active infection results from the body’s “fight or flight” response being activated. The sympathetic nervous system is stimulated by the infection, triggering the release of stress hormones, specifically catecholamines like adrenaline and noradrenaline, as well as cortisol. These hormones increase the heart rate and force of contraction while simultaneously causing vasoconstriction, a temporary narrowing of the blood vessels. The combination of increased cardiac output and narrowed vessels results in a higher pressure being exerted on the arterial walls, leading to the observed elevation in BP. This acute hypertension typically subsides as the immune system clears the infection and stress hormone levels return to baseline.
The Critical Difference: Infection and Septic Shock
While a mild infection can temporarily raise blood pressure, a severe, systemic infection often leads to the opposite and more dangerous condition: hypotension. This severe condition is known as septic shock, occurring when the body’s inflammatory response becomes overwhelming and dysregulated. Sepsis is a life-threatening complication where the body injures its own tissues and organs in response to an infection. In septic shock, the massive release of inflammatory mediators causes widespread vasodilation, meaning the blood vessels widen. This loss of vascular tone significantly reduces the resistance to blood flow, leading to a drop in blood pressure. Capillary leak syndrome can also occur, causing fluid to shift out of the blood vessels into surrounding tissues, which lowers the effective circulating blood volume. Septic shock is defined by persistent hypotension that requires medication to maintain sufficient blood pressure. This uncontrolled drop deprives tissues and organs of necessary blood flow and oxygen, leading to organ dysfunction and mortality.
Link Between Systemic Inflammation and Chronic Hypertension
Beyond the acute changes during illness, research suggests a connection between chronic, low-grade systemic inflammation and the development or worsening of long-term hypertension. This link focuses on effects that persist long after a specific infection has resolved. Sustained inflammation triggers changes in the structure and function of the blood vessels. This chronic inflammatory state damages the endothelium, the inner lining of the arteries responsible for regulating blood vessel tone. Endothelial dysfunction impairs the blood vessel’s ability to properly relax and contract, leading to increased stiffness and resistance. Arterial stiffness is a major factor that contributes to elevated blood pressure over time. The activation of immune cells and the sustained release of inflammatory cytokines promote this vascular remodeling process. Certain infectious agents or chronic inflammatory conditions, such as autoimmune diseases, may accelerate this damage, contributing to chronic hypertension.
Monitoring Blood Pressure During Illness
For those with a history of hypertension, monitoring blood pressure during an illness provides important health data. Temporary, slightly elevated readings are common, but look for sustained high readings significantly above your typical range. Maintain hydration, as fever and illness can lead to fluid loss that affects readings. Seek immediate medical attention if you experience symptoms like sustained high blood pressure readings, severe headache, or vision changes. Conversely, a sudden drop in blood pressure accompanied by signs like lightheadedness, dizziness, or confusion could signal a serious systemic infection or septic shock. Symptoms of shock, such as cold or clammy skin, rapid heart rate, or shortness of breath, require emergency care. Always consult with a healthcare professional to interpret blood pressure readings during illness, especially if you take medication for hypertension.