Illness often causes physiological changes, including an elevated heart rate. This temporary increase is a frequent response as the body combats infection or inflammation. Understanding this natural process helps individuals recognize what is happening during sickness.
Physiological Reasons for Heart Rate Elevation
When the body encounters illness, it activates the sympathetic nervous system, or “fight or flight” system. This releases stress hormones like adrenaline, signaling the heart to beat faster and stronger, meeting the body’s increased demands while fighting infection.
Fever, a common illness symptom, contributes to an elevated heart rate. Rising body temperature increases metabolic rate, demanding more oxygen and nutrients. The heart pumps blood faster to support this activity and dissipate excess heat. For every one-degree Fahrenheit increase, heart rate can rise by about 10 beats per minute.
Dehydration, often caused by vomiting, diarrhea, or reduced fluid intake during illness, strains the cardiovascular system. It decreases blood volume, making blood thicker and harder to circulate. To maintain adequate blood flow and oxygen delivery, the heart works harder and pumps faster. Dehydration can also disrupt electrolyte balance, affecting heart rhythm.
The immune system’s response to infection releases inflammatory mediators like cytokines. These substances, including interleukins and tumor necrosis factor, influence heart function and increase heart rate. Inflammation can expand blood vessels, prompting increased heart rate and blood flow to affected areas as a defense mechanism.
Recognizing Concerning Heart Rate Changes
A normal resting heart rate for most adults ranges between 60 and 100 beats per minute. While an elevated heart rate is expected when sick, know when the increase might indicate a more serious issue. If your heart rate remains persistently above 100 beats per minute at rest, especially exceeding 120 beats per minute, it warrants attention.
Certain accompanying symptoms with an elevated heart rate should prompt concern. These include shortness of breath, chest pain or discomfort, dizziness, or lightheadedness suggesting fainting. Other warning signs include severe fatigue or confusion. Recognizing these indicators helps differentiate a typical illness response from a potentially more significant health problem.
Steps to Take
When experiencing an elevated heart rate due to illness, general self-care measures support recovery. Adequate rest conserves energy and helps fight infection. Staying well-hydrated is also important, as proper fluid intake maintains blood volume and reduces heart strain.
Contact a healthcare professional if you notice specific warning signs alongside an elevated heart rate. Seek medical advice if your heart rate remains consistently high, particularly above 120 beats per minute, or if you experience new or worsening symptoms like chest pain, severe shortness of breath, or persistent dizziness. Avoid self-medicating with over-the-counter drugs that might affect heart rate unless advised by a doctor.