COVID-19 infection frequently alters heart rate, both during the illness itself and for weeks or months afterward. Wearable device studies found that roughly 80 to 90 percent of infected people showed measurable shifts in resting heart rate around the time of infection, and a meaningful subset developed persistent tachycardia or autonomic dysfunction that lasted well beyond the acute phase. These changes range from subtle bumps on a smartwatch readout to debilitating conditions that limit daily activity, and the mechanisms behind them involve more than just fever or deconditioning.
Heart Rate Shifts During Acute Infection
Some of the earliest evidence for COVID-related heart rate changes came from studies using smartwatches and fitness trackers. In a Stanford-led study of nearly 5,300 wearable-device users, 32 individuals were identified as having COVID-19, and 81 percent of them showed measurable changes in resting heart rate, daily step count, or sleep duration around the time of infection. All of the detected cases showed abnormal heart rate patterns near the onset of illness, and in many cases these shifts appeared before the person had any symptoms at all.1PubMed Central. Pre-symptomatic detection of COVID-19 from smartwatch data A separate deep-learning analysis of wearable data found abnormal resting heart rate in 92 percent of confirmed cases, with the disturbances beginning on average about five days before symptom onset.2medRxiv. Deep learning-based detection of COVID-19 using wearables data
The pattern is not always a straightforward rise, though. One wearable-based study tracking symptomatic individuals found that heart rate initially increased during the first week of symptoms but then dipped below baseline from roughly day seven through day twenty-one before normalizing. Heart rate variability metrics, meanwhile, ran slightly elevated during that same window.3npj Digital Medicine. Assessment of physiological signs associated with COVID-19 measured using wearable devices This temporary drop, sometimes called relative bradycardia, has also been described clinically and is thought to be unusual compared with the typical fever-driven tachycardia seen in most infections. With the flu or a bacterial infection, heart rate generally rises in step with body temperature; in COVID, the heart rate sometimes fails to keep pace with fever, or even drifts lower during early recovery.
How Long the Changes Persist
For most people, heart rate returns to its pre-infection baseline within a few weeks to a couple of months. But a notable minority stays elevated much longer. A wearable-device study tracking COVID-positive individuals found that a subset, roughly one in seven, still showed abnormal resting heart rate more than four months after symptom onset. Among those with persistent changes, a consistent pattern emerged: nightly heart rate was elevated by about seven beats per minute above their personal baseline, representing an approximate 13 percent increase, while a key heart rate variability metric dropped from about 65 milliseconds to around 45 milliseconds.4Scientific Reports. Automatic detection of persistent physiological changes after COVID infection via wearable devices with potential for long COVID management
If you are tracking your own resting heart rate on a smartwatch and notice it is still running higher than your personal norm weeks after recovering from COVID, you are not imagining things. This is one of the more commonly reported physiological signatures of ongoing recovery. For most people it does resolve, but the timeline varies widely, and there is no clean cutoff that separates “still recovering” from “something else is going on.” Generally, if your resting heart rate remains elevated or you have persistent palpitations beyond three months, that warrants a medical evaluation.
Post-COVID Tachycardia Syndromes
Among people who develop long COVID, two related heart rate conditions stand out: postural orthostatic tachycardia syndrome and inappropriate sinus tachycardia. Both involve a heart rate that runs faster than it should, but they differ in their triggers and how they are diagnosed.
Inappropriate sinus tachycardia means the resting heart rate stays above 100 beats per minute without a clear cause like anemia, dehydration, or thyroid disease. In a study of 200 patients visiting a post-COVID clinic for symptoms lasting beyond three months, 40 patients met strict diagnostic criteria for inappropriate sinus tachycardia, giving an estimated prevalence of 20 percent among that symptomatic population. None of those patients had experienced palpitations before their COVID infection. On average, their heart rates ran about 105 beats per minute while lying down and jumped to 125 when standing.5Scientific Reports. Inappropriate sinus tachycardia in post-COVID-19 syndrome
POTS involves an excessive heart rate increase upon standing, typically defined as a rise of 30 or more beats per minute within ten minutes of going from lying down to upright, accompanied by symptoms like dizziness, lightheadedness, or fatigue. The condition has been widely reported in long COVID cohorts. One study found that 79 percent of patients referred to a post-acute sequelae clinic met established criteria for POTS, with significantly reduced heart rate variability and poorer quality of life compared to healthy controls.6PubMed Central. High Incidence of Autonomic Dysfunction and Postural Orthostatic Tachycardia Syndrome in Patients with Long COVID: Implications for Management and Health Care Planning A larger study of highly symptomatic long COVID patients found that about 31 percent met POTS diagnostic criteria, and those patients were younger (average age 40), predominantly female (91 percent), and walked significantly shorter distances on a six-minute walk test compared to long COVID patients without POTS.7PubMed. Prevalence and Clinical Impact of Postural Orthostatic Tachycardia Syndrome in Highly Symptomatic Long COVID
The range of prevalence figures reflects differences in how patients are selected and how strictly the diagnostic criteria are applied, but the general picture is clear: post-COVID tachycardia syndromes are common enough among long COVID patients that they have become a routine part of evaluation in specialized clinics. Reports indicate that many of these patients develop POTS within six to eight months of their initial infection, and the majority had no prior history of the condition.8PubMed Central. COVID-19 Induced Postural Orthostatic Tachycardia Syndrome (POTS): A Review
Heart Rate Variability as a Window Into Autonomic Health
Heart rate variability measures the tiny fluctuations in the interval between heartbeats. A healthy autonomic nervous system produces a lot of variation, because the heart is constantly adjusting in response to breathing, posture changes, and stress. Lower variability often signals that the body’s fight-or-flight system is overactive or that the calming side of the nervous system is underperforming. COVID appears to disrupt this balance in both acute and prolonged illness.
During hospitalization, critically ill COVID patients have shown substantially decreased heart rate variability throughout the course of illness.9PubMed Central. Decreased Heart Rate Variability in COVID-19 But the effect is not confined to severe cases. In people with long COVID, studies have documented higher resting heart rates and lower variability compared to healthy controls, both at rest and during deep breathing exercises that normally produce large swings in heart rate.10Scientific Reports. Impact of long COVID on the heart rate variability at rest and during deep breathing maneuver Wearable-device data has confirmed the same pattern outside the clinic: the drop in variability tracked alongside elevated nighttime heart rates in the subset of users with persistent post-COVID changes.4Scientific Reports. Automatic detection of persistent physiological changes after COVID infection via wearable devices with potential for long COVID management
This autonomic imbalance, sometimes called dysautonomia, is now considered a central feature of cardiovascular long COVID. Patients typically show impaired vagal (parasympathetic) activity alongside excessive sympathetic drive, which manifests as a heart that runs too fast at rest, responds poorly to position changes, and recovers sluggishly after exertion.11PubMed Central. Cardiovascular autonomic dysfunction in “Long COVID”: pathophysiology, heart rate variability, and inflammatory markers One wearable study found that among long COVID patients exercising near their first ventilatory threshold, the sympathetic-parasympathetic balance recovered more slowly than expected, suggesting that this autonomic mismatch contributes to the exercise intolerance and post-exertional malaise many patients report.12PubMed. Wearable Heart Rate Variability Monitoring, Autonomic Dysfunction and Post-exertional Malaise in Long COVID: An Observational Study
Why Exercise Feels Harder After COVID
Many people recovering from COVID notice that their heart races during activity that would have felt easy before. Part of this is deconditioning from bed rest, but invasive cardiopulmonary exercise testing has revealed something more specific. Post-COVID patients in one study showed markedly reduced peak aerobic capacity (roughly 70 percent of predicted values, versus 131 percent in controls), and the limitation was not caused by a weak heart pump. Cardiac output at peak exercise was essentially normal. The problem was in the periphery: the body’s tissues were failing to extract oxygen from the blood efficiently, with the oxygen extraction ratio cut roughly in half compared to controls.13Chest. Persistent Exertional Intolerance After COVID-19: Insights From Invasive Cardiopulmonary Exercise Testing
This distinction matters because it means the heart itself may be pumping adequately, but the muscles and tissues are not using the delivered oxygen properly. For the patient, the experience is the same: your heart rate climbs faster than it should, you feel exhausted sooner, and recovery takes longer. But the finding points toward a peripheral or vascular problem rather than a purely cardiac one, which has implications for rehabilitation. Pushing through heart rate spikes with aggressive exercise could backfire, particularly if post-exertional malaise is part of the picture.
What Is Driving These Heart Rate Changes
Several mechanisms have been proposed, and they likely work in combination rather than representing a single pathway.
The most prominent explanation centers on autonomic nervous system disruption. COVID may damage or inflame the nerves that regulate heart rate, blood pressure, and blood vessel tone. Researchers have described this as a virus- or immune-mediated disruption of the autonomic nervous system, resulting in orthostatic intolerance syndromes.14PubMed Central. Autonomic dysfunction in ‘long COVID’: rationale, physiology and management strategies A broader review of cardiovascular long COVID confirmed that autonomic disturbances, including POTS and orthostatic hypotension, sit alongside myocarditis, arrhythmias, and reduced exercise capacity as part of a wide constellation of post-infection cardiovascular effects.15Oxford Academic (Cardiovascular Research). The complexity of cardiovascular long COVID: where we are
An emerging line of evidence points to autoantibodies. Some patients with long COVID produce antibodies that target receptors involved in blood vessel regulation and heart rate control. A study found that autoantibodies against several G-protein-coupled receptors, including angiotensin II receptors and adrenergic receptors, were associated with heart rate variability alterations in long COVID patients.16Journal of Allergy and Clinical Immunology. Autonomic dysfunction and vasoregulation in long COVID-19 are linked to anti-GPCR autoantibodies If the immune system is producing antibodies that bind to the very receptors controlling heart rate and vascular tone, it would explain why the autonomic dysfunction can persist long after the virus itself has been cleared.
There is also a vascular and endothelial component. COVID is known to damage blood vessel linings, and lasting endothelial dysfunction could contribute to both the impaired oxygen extraction seen during exercise and the inappropriate cardiovascular signaling that drives tachycardia at rest. Myocarditis, or inflammation of the heart muscle itself, has been documented in some patients, though systematic reviews suggest clinically significant myocarditis is relatively uncommon and does not explain the majority of post-COVID heart rate changes.
Children and Adolescents Are Not Exempt
The assumption that post-COVID heart rate problems are an adult phenomenon does not hold up. A case-controlled study of children and adolescents with long COVID found significant autonomic cardiac changes compared to healthy peers: lower heart rate variability on key measures and substantially different frequency-domain patterns, suggesting the same kind of autonomic imbalance seen in adults.17PubMed Central. Autonomic cardiac function in children and adolescents with long COVID: a case-controlled study Emerging evidence indicates that both inappropriate sinus tachycardia and POTS may be important clinical features in pediatric long COVID, mirroring what has been seen in adult studies.18Current Clinical Microbiology Reports. Post-COVID Postural Orthostatic Tachycardia Syndrome and Inappropriate Sinus Tachycardia in the Pediatric Population
For parents, this means that a child complaining of a racing heart, dizziness when standing, or unusual exercise intolerance after a COVID infection is describing something physiologically real. Pediatric long COVID clinics are beginning to screen for these autonomic syndromes, though awareness remains uneven.
How Post-COVID Tachycardia Compares to Other Post-Viral Syndromes
POTS and autonomic dysfunction are not unique to COVID. They have long been associated with other infections and with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). A comparative study found that both post-COVID and ME/CFS patients showed dysautonomia and small fiber neuropathy, though the ME/CFS group actually had higher heart rates and a higher prevalence of POTS (31 percent versus about 14 percent in the post-COVID group).19PubMed Central. Dysautonomia and small fiber neuropathy in post-COVID condition and Chronic Fatigue Syndrome The overlap between these conditions is striking and suggests shared mechanisms: viral infection triggers immune and nervous system disruption that outlasts the infection itself. COVID has simply brought vastly more cases into clinical view at once, accelerating research into post-infectious autonomic dysfunction that had been underfunded for decades.
Managing Post-COVID Heart Rate Problems
Treatment depends on what exactly is going on. For patients with confirmed POTS or inappropriate sinus tachycardia, management typically involves a combination of medications and lifestyle modifications.
Beta-blockers are the most commonly prescribed first-line option. In a small case series of post-COVID autonomic dysfunction patients, beta-blockers were given to over half of those treated, and 80 percent of beta-blocker patients reported improved or resolved symptoms at follow-up.20PubMed Central. Autonomic dysfunction post–acute COVID-19 infection However, some patients do not tolerate beta-blockers well, particularly if they also have low blood pressure or fatigue.
Ivabradine, a medication that slows heart rate without lowering blood pressure, has shown promising results specifically for post-COVID tachycardia. In a prospective study of 55 patients with post-COVID POTS, about 78 percent reported significant symptom improvement within a week of starting ivabradine, with meaningful reductions in 24-hour heart rate and improvements in heart rate variability.21PubMed Central. Ivabradine effects on COVID-19-associated postural orthostatic tachycardia syndrome: a single center prospective study A comparison trial found ivabradine brought heart rate down by an average of about 39 beats per minute (from roughly 122 to 84) versus about 23 beats per minute with carvedilol, a beta-blocker, and palpitation relief was better in the ivabradine group (92 percent versus 67 percent).22PubMed Central. ‘Ivabradin’ versus ‘Carvedilol’ in the management of Post-COVID-19 palpitation with sinus tachycardia
Non-drug strategies are equally important, especially for POTS. Increased salt and fluid intake helps expand blood volume, which can reduce heart rate spikes upon standing. Compression garments support blood return from the legs. Exercise is recommended, but the approach matters: a structured, progressive program that starts with non-upright activities like swimming, rowing, or recumbent cycling tends to work best, because upright exercise can worsen symptoms early on. A progressive three-month exercise regimen has been shown to reduce standing heart rate and improve POTS symptoms.23PubMed Central. Postural orthostatic tachycardia syndrome and post-acute COVID-19 The key is gradual progression; the instinct to push through and “get back to normal” quickly can trigger post-exertional crashes that set recovery back.
When Your Symptoms Persist Longer
Among patients whose post-COVID syndrome drags on for many months, the autonomic profile may actually shift over time. A study examining heart rate variability in long-term post-COVID patients found that those with longer-lasting symptoms showed a lower daytime ratio of sympathetic to parasympathetic activity and overall higher parasympathetic activation compared to those who recovered sooner.24Scientific Reports. Autonomic dysregulation in long-term patients suffering from Post-COVID-19 Syndrome assessed by heart rate variability This is somewhat counterintuitive, because early post-COVID autonomic dysfunction often features an overactive sympathetic system. The shift may reflect the body’s attempt to compensate over time, or it may indicate that different mechanisms dominate at different stages of recovery. Either way, it suggests that the autonomic picture is not static and that treatment strategies may need to adapt as the condition evolves.
For anyone tracking their own heart rate data after COVID, the practical takeaway is that both persistent elevation and unusual dips can be meaningful. A wearable showing consistently elevated nighttime heart rate weeks after recovery is worth flagging to a doctor, as is the onset of palpitations, lightheadedness when standing, or unexplained exercise intolerance. These are not anxiety symptoms or signs of being out of shape. They reflect measurable physiological changes that have well-documented causes and, in many cases, respond to targeted treatment.