An elevated heart rate is common when experiencing illness. This increase is a natural physiological response, indicating the body is working to combat sickness. It is a temporary adjustment by the cardiovascular system to the demands placed on it during illness.
Why Sickness Elevates Heart Rate
When the body fights an illness, its immune system activates, requiring more energy. This increased metabolic demand causes the heart to work harder, pumping blood and oxygen throughout the body. The heart and immune system are integrated, communicating through various signals.
A primary factor contributing to an elevated heart rate during illness is fever. As body temperature rises, the heart pumps faster to circulate blood and regulate temperature. For every 1°F (0.56°C) increase, heart rate can rise by approximately 10 beats per minute. This response enhances the delivery of immune cells and proteins to affected areas.
Dehydration also increases heart rate during sickness. Illnesses can lead to fluid loss through fever, sweating, vomiting, or diarrhea. When the body loses more fluids than it takes in, blood volume decreases. The heart compensates by beating faster to maintain blood pressure and ensure oxygen and nutrients are delivered to organs.
The body’s stress response also contributes to an elevated heart rate. Being sick can trigger the sympathetic nervous system, the “fight or flight” response. This system releases stress hormones like adrenaline and noradrenaline, which signal the heart to beat faster and stronger. Inflammation, a part of the healing process, can cause blood vessels to expand, requiring the heart to increase its rate to deliver white blood cells and proteins to damaged tissues.
When to Be Concerned About an Elevated Heart Rate
While an elevated heart rate is often a normal response to illness, certain signs indicate a need for medical attention. A resting heart rate consistently above 100 beats per minute (bpm) in adults warrants concern. For children, a significant and persistent increase above their typical range should be noted.
Accompanying symptoms signaling a need for medical evaluation include chest pain, shortness of breath, difficulty breathing, dizziness, lightheadedness, or fainting spells. Other concerning signs include severe fatigue, confusion, or a weak and rapid pulse, which should prompt immediate medical consultation.
Individuals with pre-existing conditions, such as heart conditions or those on certain medications, may be more vulnerable to complications from dehydration or an increased heart rate during illness. Age is another factor, as the elderly or very young may respond differently to illness.
Managing an Elevated Heart Rate When Sick
If an elevated heart rate is not accompanied by concerning symptoms, supportive measures can aid recovery. Adequate rest is important, as it allows the body to conserve energy and focus on fighting the illness. Minimizing physical and emotional stress also supports healing.
Staying well-hydrated is another helpful strategy. Drinking plenty of water, clear broths, or electrolyte-containing fluids replaces lost fluids and supports blood volume. This reduces strain on the heart, allowing it to pump blood more efficiently.
Managing fever can also help reduce heart rate. Using cool compresses or maintaining a comfortable room temperature can alleviate discomfort and lessen the heart’s workload. Following medical advice for underlying illnesses and taking prescribed medications is important for overall recovery.