Resting heart rate (RHR) is the number of times your heart beats per minute while your body is at complete rest. This measurement offers insights into cardiovascular health and overall bodily function. While RHR fluctuates throughout the day based on activity and emotions, a consistent baseline provides valuable information. Various factors can influence this rate, including illness, which often prompts noticeable changes.
Understanding Resting Heart Rate
Resting heart rate (RHR) is measured when an individual is calm, relaxed, and not physically active, typically after at least five minutes of rest. For most adults, a normal RHR falls within 60 to 100 beats per minute (bpm). Athletes or very fit individuals often have a lower RHR, sometimes between 40 and 60 bpm, indicating a more efficient heart.
RHR can be measured manually by checking your pulse at the wrist or neck, or using wearable fitness trackers and smartwatches. Several factors influence RHR, including age, fitness level, body size, emotions like stress, certain medications, and air temperature.
How COVID-19 Affects Resting Heart Rate During Illness
During an acute COVID-19 infection, an elevated resting heart rate is common. This physiological response is due to the body’s immune system combating the SARS-CoV-2 virus. When fighting an infection, the body launches an inflammatory response, increasing metabolic demands and requiring the heart to work harder to circulate blood and immune cells.
Fever, a common symptom of COVID-19, also increases RHR. For every degree Celsius rise in body temperature, heart rate can increase by approximately 10 beats per minute. This heightened metabolic activity places an additional burden on the cardiovascular system, prompting the heart to pump more frequently.
The SARS-CoV-2 virus can also directly impact the cardiovascular system. It can bind to ACE2 receptors on heart muscle cells, potentially leading to cardiac injury or myocarditis. This direct viral interaction, or the immune system’s overreaction, can further increase RHR during the acute phase. Dehydration, often accompanying fever, vomiting, or diarrhea, can also thicken the blood, making it harder to circulate and prompting a faster heart rate.
Resting Heart Rate as a Monitoring Indicator
Changes in RHR can serve as a useful, though not definitive, indicator of illness, including COVID-19. Wearable devices, such as smartwatches and fitness trackers, continuously monitor RHR, establishing a personalized baseline. A sustained increase in RHR above this baseline, even before other symptoms appear, might signal the onset of an infection or indicate physiological stress.
Monitoring trends in RHR can provide insights into the body’s response to an infection or its recovery. A continued elevation in RHR might suggest an infection is worsening or that the body is still struggling. Conversely, a gradual return of RHR to baseline levels often indicates recovery and subsiding inflammation.
RHR is just one piece of the health puzzle and should not be used as the sole diagnostic tool for COVID-19. Factors like stress, sleep deprivation, or caffeine intake can also temporarily elevate RHR, necessitating a holistic view of symptoms and other health metrics. While a sustained RHR increase can be a signal to pay closer attention to one’s health, professional medical advice and diagnostic testing remain the definitive methods for confirming illness.
Post-COVID Resting Heart Rate Changes
Many individuals experience lingering changes in their resting heart rate after the acute phase of a COVID-19 infection. This phenomenon is particularly noted in those who develop “long COVID,” where symptoms persist for weeks or months beyond initial recovery. Some people may observe a persistently elevated RHR, a condition known as tachycardia, or issues with heart rate variability, which reflects the body’s ability to adapt its heart rate.
These prolonged RHR abnormalities are often linked to the virus’s impact on the autonomic nervous system (ANS). The ANS regulates involuntary bodily functions, including heart rate, blood pressure, and breathing, through its two branches: the sympathetic (“fight or flight”) and parasympathetic (“rest and digest”) systems. COVID-19 can disrupt the delicate balance of these systems, leading to dysautonomia, where the ANS does not function correctly. This imbalance can manifest as an increased baseline heart rate or an exaggerated heart rate response to mild activity.
Lingering inflammation following the infection can also contribute to a sustained higher RHR. While the initial viral assault subsides, the body’s immune response might continue to affect various systems, including the cardiovascular system. Conditions like Postural Orthostatic Tachycardia Syndrome (POTS), characterized by a significant increase in heart rate upon standing, have been reported in some individuals post-COVID, further highlighting the autonomic nervous system’s involvement.
If you notice a persistently elevated resting heart rate, heart palpitations, dizziness, or unusual fatigue after recovering from COVID-19, consult a healthcare professional. These symptoms, especially if they do not improve over several weeks, warrant medical evaluation to determine the underlying cause and discuss appropriate management. A doctor can assess your condition and provide guidance tailored to your specific health needs.