Fever and Blood Pressure: What’s the Connection?
Medical Disclaimer
This article is for informational purposes only and does not substitute professional medical advice. Always consult a healthcare provider.
Normally, our body keeps its temperature within a narrow range, and minor fluctuations don’t usually affect blood pressure. In other words, a slight increase or decrease in temperature doesn’t necessarily cause blood pressure spikes and isn’t something to worry about.
But fever changes the game. Many people with hypertension notice that their blood pressure becomes unstable during a fever, even if they strictly follow their doctor’s recommendations. In some cases, these fluctuations may require an unplanned visit to a specialist [1].
Fever triggers a whole cascade of physiological reactions. Heart rate speeds up, and blood vessels go through a two-phase process—first constricting, then dilating [2]. For people with hypertension, these shifts can lead to sudden blood pressure spikes since their regulatory system doesn’t work as efficiently. So yes, fever does impact the cardiovascular system, but it’s not a straightforward cause-and-effect relationship—it depends on individual factors.
For healthy individuals, these changes usually don’t pose a threat. But for those with hypertension, blood pressure can fluctuate dramatically. On top of that, fever leads to fluid and electrolyte loss, which further affects the heart and blood vessels. That’s why acute infections are considered a risk factor for worsening hypertension and other cardiovascular conditions [3]. That’s why it’s important to monitor blood pressure during illness and consult a doctor if needed.
References
[1] Zenglei Zhang et al. “Role of Inflammation, Immunity, and Oxidative Stress in Hypertension: New Insights and Potential Therapeutic Targets.” In: Frontiers in Immunology 13 (Jan. 2023). ISSN: 1664-3224. DOI: 10.3389/fimmu.2022.1098725.
[2] John E. Hall and Michael E. Hall. Guyton and Hall Textbook of Medical Physiology. 14th edition. Philadelphia, PA: Elsevier, 2021. ISBN: 978-0-323-59712-8 978-0-323-67280-1.
[3] Pyry N. Sipilä et al. “Severe Infection and Risk of Cardiovascular Disease: A Multicohort Study.” In: Circulation 147.21 (May 2023), pp. 1582–1593. ISSN: 0009-7322, 1524-4539. DOI: 10.1161/CIRCULATIONAHA.122.061183.
