Short answer
Long COVID pacing with heart rate and HRV uses two signals to stay under a limit you cannot feel in the moment: daytime heart rate kept below a personal ceiling (often resting heart rate plus 15 bpm as a first estimate), and a morning HRV and resting heart rate check against your own average. Your symptoms still decide.
If you crash two days after a day that felt fine, you are not imagining it, and it is not weakness. With post-exertional malaise the bill arrives late. Before you blame yourself, check what your body already recorded — the numbers can sometimes show the day it started.
Note: this article is for education and is not medical advice. Pacing is a self-management approach, not a cure for Long COVID. Every heart rate ceiling here is an estimate to discuss with your clinician, especially if you take medicines that change heart rate, faint, or have a heart condition.
You don't have to work this out alone.
Welltory runs Energy Lab, a paid, moderated online community for women aged 35 to 65 living with Long COVID and other energy-limiting conditions, where members learn to read their own heart rate, HRV and crash data together. It is education and peer support, not medical care. Join Energy Lab here · what the community is, who it is for and what it costs
Why Long COVID pacing is different from "just take it easy"
Most people with Long COVID hear one of two pieces of advice. One is to rest until you feel better. The other is to get moving again, because inactivity makes everything worse. Both can be right for someone. Neither is right for everyone, and the reason is one symptom: post-exertional malaise (PEM).
PEM is a worsening of symptoms after physical, cognitive or emotional effort that is out of proportion to the effort and arrives late. The UK's National Institute for Health and Care Excellence (NICE) describes it in its ME/CFS guideline as symptoms that "typically worsen 12 to 48 hours after activity and last for days or even weeks." Our guide to post-exertional malaise covers it in depth. For Long COVID the point is simple: it is common. In an international survey of 3,762 people with Long COVID from 56 countries, 85.9% reported relapses, mainly triggered by exercise, physical or mental activity, and stress.
PEM is not "being unfit". In a 2024 study in Nature Communications, researchers in Amsterdam took thigh muscle biopsies from 25 people with Long COVID and from people who had recovered fully, a week before and a day after a short cycling test. In the Long COVID group, metabolic disturbances, exercise-induced muscle damage and amyloid-containing deposits in the muscle got worse after PEM had been triggered. That is a physical change in tissue, not a lack of willpower.
This is why pacing exists. You cannot feel the line while you are crossing it, so you need something outside your feelings to show it. Heart rate and HRV are two of the easiest signals to get. For the wider picture of the illness, see our overview of Long COVID and the full list of Long COVID symptoms.
Should you exercise with Long COVID? It depends on PEM
This is the question behind the search for "long covid exercise intolerance", and the honest answer is that experts disagree for a reason.
In June 2025 the American Heart Association published a scientific statement on exercise intolerance in Long COVID. It describes cardiovascular deconditioning after infection and quarantine, notes that emerging data show exercise training programmes improving outcomes such as peak oxygen uptake, walking distance and fatigue, and recommends an exercise prescription tailored to the patient through shared decision-making. It also mentions the risk of "potential exacerbation of postexertional malaise". Patient organisations, including the UK ME Association, warned that for people with PEM such a programme could trigger a serious relapse.
World Physiotherapy's briefing on safe rehabilitation for Long COVID (2021) draws the line that matters for you. It says people "should be screened for post-exertional symptom exacerbation" before activity is prescribed, that "graded exercise therapy or fixed activity prescription should not be used" when it is present, and that "pacing is not an activity avoidance strategy". It lists heart rate monitoring among the approaches that can support self-management.
So the first job is not to pick a workout. It is to find out whether you have PEM:
Does effort cost you more a day or two later than it did at the time?
Is the cost out of proportion — a shower, a supermarket trip or a hard conversation followed by a day in bed?
Do you take a day or more to get back to your usual?
If the answer is yes, you are pacing first and treating exercise with care. Clinicians often use the DePaul Symptom Questionnaire PEM subscale (DSQ-PEM) to screen for this; you can ask for it. If the answer is clearly no, ordinary graded rehabilitation with your clinician may suit you, and this article is less relevant. If you are not sure, treat it as possible PEM and ask your clinician to screen for it before you start an exercise programme.
What your heart rate tells you with Long COVID
Heart rate is the signal you can watch all day, which is why it is the backbone of heart rate pacing. With Long COVID it carries three kinds of information.
Your resting heart rate may have moved. In a 2021 study in JAMA Network Open that followed 234 people with COVID-19 through their wearables, resting heart rate took on average 79 days after symptom onset to return to baseline, and in 13.7% it stayed more than 5 beats per minute above baseline for over 133 days. If your resting heart rate is higher than it was before you got ill, you are not imagining it. It also means your ceiling has to be built on your current resting heart rate, not your old one.
Standing up can be a load on its own. Many people with Long COVID develop orthostatic intolerance or postural orthostatic tachycardia syndrome (POTS): heart rate climbs sharply on standing and stays high. A shower, cooking, or a queue can push your pulse over a ceiling without any obvious "exercise". If that sounds familiar, our guide to the stand test at home explains what clinicians look for, and the diagnosis itself belongs with a clinician.
Your heart rate ceiling is an estimate, not a measurement. The most common starting point comes from the Workwell Foundation: average your waking resting heart rate over seven days and add 15 beats per minute. With an average of 72 bpm, that gives a ceiling of about 87 bpm. Workwell calls this a conservative estimate of the point where the body starts leaning on less efficient, anaerobic energy production. A 2026 study of 121 people with Long COVID gives the idea some support: after exercise at intensities around the first ventilatory threshold, patients' HRV stayed lower than healthy controls' for 24 hours, and the authors suggested that PEM risk rises above that threshold.
The ceiling is not proof of safety. Plenty of people crash while staying under it, because some loads — thinking, emotion, noise, heat — barely move the pulse. Our article on why you can crash with zero steps covers that side.
What morning HRV tells you with Long COVID
Heart rate variability (HRV) is the small, changing gap between heartbeats. At rest, a larger and more flexible gap mostly reflects the "rest and digest" side of the nervous system. Long COVID tends to lower it: a 2023 study of 21 people with Long COVID and 20 controls found lower HRV lying down and during deep breathing.
For pacing, HRV is most useful as a morning check: one reading, taken the same way each day, compared with your own recent average. Our guide to morning HRV pacing goes through the method in detail. Three things are specific to Long COVID.
It can show the cost of yesterday. In the 2026 study above, which recorded heart rate and HRV continuously, patients' night-time HRV fell after more intense and longer exercise. A lower-than-usual morning after a big day is a reason to plan a smaller one.
A "good" number can mislead. Welltory's help center notes that for some people with ME/CFS, POTS, Long COVID or fibromyalgia, a spike in HRV, or an unusually good-looking reading, can show up in the middle of a crash rather than during real recovery. A calmer number here can mean the body has less left to react with, not more. We cover this in when a good HRV reading is not good news.
One morning is weather; a week is information. Short sleep, a late meal, alcohol, the menstrual cycle and an infection all move morning HRV. Read the trend over several mornings before you read meaning into it.
Where is your limit? Reading heart rate, HRV and symptoms together
No single signal shows your limit. Together they narrow it down. Here is one way to lay them out — options to consider, not instructions. Your clinician and your own energy management plan come first.
| Signal | What to look at | What it can suggest | What it cannot tell you |
|---|---|---|---|
| Heart rate during the day | Time spent above your ceiling (for example resting + 15 bpm) | You crossed the line your plan is built around | Cognitive, emotional or sensory load that barely moves the pulse |
| Resting heart rate | Waking or overnight value vs your own recent average | A higher morning after a busy day can mean you are still paying for it | Whether the change is PEM, infection, poor sleep or a new medicine |
| Morning HRV | Reading vs your own average, as a 7-day trend | Several lower mornings can be a reason for a lighter few days | Your energy limit; a high reading during a crash is not a green light |
| Your body | Heavy limbs, sore throat, thicker brain fog, unrefreshing sleep | The most direct report you have | Nothing — when it disagrees with the numbers, your body wins |
| The last 24–48 hours | What you did, including talking, screens, heat and standing | Where today's cost probably came from | Which single activity caused it; patterns need several examples |
The rule is asymmetric. The numbers can make you more cautious. They should never be the reason you push past symptoms. A good morning reading is exactly where boom-and-bust starts; our article on the boom and bust cycle explains why.
A daily Long COVID pacing routine with heart rate and HRV
This is one routine that combines both signals. Adapt it; drop any step that costs more energy than it gives.
1. Morning: check before you plan. Before you get up, take your morning reading in the same position every day — lying down is fine and often better with orthostatic symptoms. Note your resting heart rate and HRV against your usual, then ask yourself one question: "How do I feel compared with my ordinary day?" If two of the three point down, plan a smaller day.
2. Plan the day inside the envelope. Decide your essentials first and leave a buffer. Many people use the 50% rule: plan to do about half of what you think you could, and stop before you feel tired. If you have not found your sustainable level yet, start with the energy envelope.
3. During the day: let the pulse interrupt you. Set the ceiling on a watch or chest strap that can alert you. When it goes off, stop, sit or lie down, and let your heart rate settle before you carry on — not after you finish the task. Do tiring tasks sitting where you can: showering on a stool, chopping vegetables at the table.
4. Break up the load. Short bursts with rest in between cost less than one long effort. Alternate physical, thinking and social tasks rather than stacking three of the same kind.
5. Evening: log, don't judge. Write down what you did, including talking, screen time, heat and standing, and how you felt. Tag anything unusual: a long call, a hot shower, an appointment, period day 1, a short night. You are building a record, not a report card.
6. Look back after 48 hours. PEM runs on a delay, so the useful question is "what happened two days ago?" Compare your mornings after big days with your mornings after quiet ones. After a few weeks you may see your own pattern: how many hours later the cost arrives and how long your mornings take to come back.
What to do on a bad day with Long COVID
A bad day might be an ordinary low day or the start of a crash. You do not have to tell them apart before you act; treat it as a possible crash and cut back.
Stop early, not late. Cancel or postpone what you can. The cost of resting on a day that turns out fine is small; the cost of pushing into a crash can be days or weeks.
Lower the load from standing. Lie down or put your feet up rather than sitting upright if standing makes your heart race. Keep essentials within reach.
Shrink the input, not only the movement. Dim the screen, keep calls short or move them to text, lower noise and light. Cognitive and emotional effort counts.
Run your crash plan. Decide in advance, on a good day, what a crash day looks like: who covers meals or school runs, which messages you send, what you eat when you cannot cook. If your clinician has advised fluids, salt or medicines for orthostatic symptoms, follow their plan; do not start new ones on your own.
Don't test yourself. A bad day is not the day to check whether you are "really" that limited. A bad day is not a failure of pacing either; crashes happen even with careful pacing.
Come back slowly. When the crash lifts, return to your usual in small steps based on how you feel and on your morning numbers, not on fixed increases. NICE warns against programmes that use fixed incremental increases in physical activity for ME/CFS, and World Physiotherapy says the same for Long COVID with post-exertional symptoms.
Log it. Note when it started, how bad it was, what came before and what helped. That record is what will make the next bad day easier to plan for.
Know when it is not a crash. Chest pain, fainting, sudden severe breathlessness, new weakness or numbness on one side, or confusion need urgent care: call 911, whatever your heart rate or HRV shows.
What heart rate and HRV can't tell you
Pacing with numbers helps many people, but it has real limits. You deserve to hear them before you build your days around a watch.
No app or wearable predicts a crash. As of 2026 we are not aware of any validated algorithm that tells you on Tuesday that Thursday will go badly. What you get is a record of your own patterns.
Activity alerts alone did not beat a simpler approach in a trial. In a 2026 randomised controlled trial in Nature Communications, 250 adults with Long COVID were assigned to a pacing app with a Fitbit that sent alerts at 50%, 75% and 100% of a personalised activity limit, or to an app without the tracking features. After six months, the tracker group did not reduce PEM more than the comparison group; both groups improved over time. Feedback from a device is a tool, not a treatment.
Small studies, mostly uncontrolled. A 2023 study of a structured five-phase pacing protocol in 31 people with post-COVID syndrome found post-exertional episodes fell from 3.4 in the first week to 1.1 in the sixth, about 16% a week. There was no control group, so it shows the approach can help, not how much. Heart-rate-guided pacing has a 2025 feasibility study of 47 people with ME/CFS or Long COVID, not a large trial.
Medicines change the numbers. Beta-blockers, ivabradine and some other medicines lower heart rate and can shift HRV. Your ceiling and your "usual" have to be reset with your clinician when a medicine starts or changes.
Wrist sensors miss beats. Optical heart rate on the wrist is less accurate during movement and in some skin and arm positions. A 2020 analysis in npj Digital Medicine found optical wrist sensors were least accurate during activity, which is exactly when a pacing alert matters. A chest strap is more precise if exact numbers matter to you.
The data can be green while you are crashing. People with energy-limiting conditions regularly describe days when every metric looks fine and their body says otherwise. Believe your body. Our article on what to do when your metrics disagree with how you feel explains why it happens.
Pacing has several tools besides heart rate and HRV — spoon theory, activity counting, diaries, the energy envelope. Our complete guide to pacing with chronic illness compares all of them, and our review of pacing apps shows what each one measures.
Living with Long COVID pacing: the questions people ask next
Will I ever be able to exercise again with Long COVID?
Many people with Long COVID improve over time, and some return to exercise, but nobody can promise when. If you have post-exertional malaise, the path back is usually slow and led by symptoms, not by fixed weekly increases. World Physiotherapy advises screening for post-exertional symptoms first and not using graded exercise therapy or fixed activity prescriptions when they are present. Gentle movement inside your envelope — stretching lying down, short walks below your heart rate ceiling — is often where people start, with a clinician who understands PEM.
Is a high heart rate after COVID dangerous?
A raised resting heart rate after COVID is common: in a 2021 wearable study, resting heart rate took 79 days on average to return to baseline, and 13.7% of people still had a resting heart rate more than 5 bpm above baseline after 133 days. It can reflect changes in the autonomic nervous system, but heart problems such as inflammation of the heart muscle need to be ruled out by a clinician. Get prompt care if a fast heart rate comes with chest pain, fainting, breathlessness at rest or a pulse that will not settle. For pacing, build your ceiling on your current resting heart rate.
What should I do if my heart rate goes over my limit in the shower?
Showers are a common trigger in Long COVID: standing, heat and lifting your arms all raise heart rate. Options people use are a shower stool, cooler water, a shorter wash, washing hair separately or less often, and sitting down to dry and dress. Some move showers to the evening so the cost does not land at the start of the day. If your heart rate climbs sharply every time you stand, mention it to your clinician; it can be a sign of orthostatic intolerance or POTS.
Can I use HRV pacing for Long COVID if I only have my phone?
For the morning check, yes. A phone camera reading — fingertip over the camera and flash — can give a resting HRV snapshot if you keep still, and you can compare it with your own average over time. What a phone cannot do is watch your heart rate through the day, so it cannot warn you when you cross a ceiling. For that part of Long COVID pacing you need a watch or chest strap that records continuous heart rate and can alert you.
Does my menstrual cycle change my Long COVID pacing numbers?
It can. A 2019 meta-analysis of 37 studies found that parasympathetic HRV tends to fall from the follicular to the luteal phase, with the lowest values usually in the days before a period, and many women with Long COVID notice symptoms flare around their period. A few lower mornings before your period may reflect the cycle rather than overdoing it. Logging your cycle next to your readings for a few months makes the pattern easier to see and to plan around.
Can I keep working while pacing with Long COVID?
Some people can, often with changes: fewer hours, more working from home, breaks between meetings, sitting for tasks usually done standing. Your heart rate and morning readings can help you show what a working day costs — for example, mornings that stay lower for two days after an office day. That kind of record can support a conversation with your employer or occupational health about adjustments. If work keeps pushing you into crashes, that is information about the workload, not about your character.
Does Long COVID pacing help in the long run?
Pacing does not cure Long COVID, and the research on it is still small. A 2023 study of a structured pacing protocol in 31 people with post-COVID syndrome found fewer post-exertional episodes and better self-rated health over six weeks, but it had no control group. What pacing aims to do is reduce the crashes that cost you weeks, so you have a steadier base. Judge it by what you can do without crashing over months, not by any single number.
How to bring this up with your doctor
You do not need a tracker to be taken seriously. But a few weeks of consistent records can make a short appointment go much further.
Lead with function. "Before COVID I worked full time and walked the dog every day. Now a supermarket trip puts me in bed the next day, and if I push, I'm worse for three days." That describes post-exertional malaise more clearly than any chart.
Ask about PEM directly. Ask whether your symptoms fit post-exertional malaise and whether they can screen for it, for example with the DePaul Symptom Questionnaire PEM subscale. Ask for that to be noted before any exercise programme is discussed.
Bring a one-page summary. Your main problem in one line; what you could do before and what you can do now; your crash pattern (what sets it off, how many hours later, how long it lasts); and, if you have it, a few weeks of resting heart rate and morning HRV with crashes marked.
Ask about orthostatic symptoms. If your heart races when you stand, ask whether an active stand test or a tilt-table test makes sense to check for POTS.
Ask about medicines and your numbers. If you start or change anything that affects heart rate, ask how to reset your ceiling.
Know what to question. If you are offered a programme with fixed increases in activity and you have PEM, you can point to World Physiotherapy's Long COVID guidance and NICE's ME/CFS guideline, which advise against it. Ask instead for an energy management plan.
Say what you are not asking for. "I'm not asking you to read my app. I'm showing you that my mornings drop for two days after a busy day, which matches how I feel."
Before you blame yourself, check what your body already recorded
If you are pacing with Long COVID, the thought that comes after a crash is usually some version of "I should have known better" or "I'm just weak now". Most people with Long COVID were busy, capable people before they got ill, and the urge to push is a habit, not a flaw.
What usually happened is visible in hindsight. A higher resting heart rate the morning after the appointment. A day spent standing in the kitchen. A long, emotional phone call. Two short nights. Your body recorded the cost before you felt it.
You are not failing at pacing. You are learning a limit that moves and cannot be felt in real time. Change one thing — a lower heart rate ceiling, a seated shower, a planned rest after every appointment — and watch your mornings for one to two weeks. That is how the pattern becomes yours.
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How Welltory helps — and what it cannot do
The limits first. Welltory is a general wellness product, not a medical device. It does not diagnose, predict, monitor, prevent or treat Long COVID, post-exertional malaise, POTS or any other condition, it cannot tell you your energy limit, and it is not a heart rate alarm: for a live ceiling alert you need a watch or strap with its own alerts. What it can do is keep a steady record of your signals next to your own notes, so the pattern is not left to memory.
1. Take a morning reading. Use your phone camera, a compatible chest strap such as a Polar H10, or an Apple Watch, Samsung Watch or Google Pixel Watch (series 2, 3 and later). Measure after waking, before coffee, a shower or breakfast, in the same position each day. Welltory needs a week or two of regular morning readings to form your personal baseline.
2. Compare with your own normal. On iOS, the Today screen compares today's HRV with your own average over the past 60 days and shows Battery, resting heart rate, stress and sleep. Read them as trends beside how you feel. When they disagree with your body, your body wins.
3. Log a crash in Crash Tracker. If you are a new English-language iOS user who reported Long COVID, ME/CFS or POTS during onboarding, Welltory offers Crash Tracker: you record when a crash began and ended, its severity, symptoms, what came before, what you did and whether it helped. Logging is free. With a subscription and at least 14 reliable days of data, it shows your active time, stress time and HRV against your own baseline for the days around each crash. "What came before" is context, not proof of a cause, and the charts do not predict crashes.
4. Tag what happened. On iOS with an Apple Watch or Oura sending heart rate through the day, Welltory flags stress episodes and asks "What happened?" — tap a suggested tag, type, or just talk: "long call", "hot shower", "appointment", "standing in a queue", "period day 1", "short night".
5. Let My Patterns collect the context. After roughly two to three weeks — insights typically need at least 7 occurrences of a tag in the current month, with some history from the month before — My Patterns shows which tags appear most often in your stress episodes, rare tags your body responds to strongly, and a full list of every time a tag appeared.
6. Build a personal log for your doctor or appointment. Your Journal keeps measurements, tags, notes and crash entries together. From the Welltory web app you can export a CSV (Dashboard → choose a chart → Export) for your one-page summary.
Patterns you find are personal associations to discuss with your doctor — not proof of a trigger, and not a warning system.
Where you can learn this with other people. Reading your own data while you are ill is hard, and most people do it alone. Energy Lab is Welltory's paid, moderated online community for women aged 35 to 65 living with energy-limiting conditions such as Long COVID, ME/CFS, POTS and fibromyalgia. You keep collecting your data in the app, and the Lab is where members learn to read it together, alongside women whose bodies behave in similar ways. Welltory's health educators and medical board answer the group's questions in plain language; there are no one-to-one consultations. It is education and peer support, not medical care, and it does not replace your own clinician. Read what the community is, who it is for and what it costs.
How we made it
Made with AI tools, then edited and fact-checked by the Welltory team. See our Editorial & AI policy.
Jane Smorodnikova, co-founder of Welltory, built the methodology behind how we read physiological data.
Written by Tatsiana Yashyna.
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This article is for educational purposes only and is not medical advice. Pacing is a self-management strategy, not a treatment, and does not cure Long COVID. No app or wearable measures your energy limit or predicts a crash, and every heart rate ceiling in this article is an estimate to agree with your clinician, especially if you take medicines that change heart rate. Graded exercise therapy and fixed activity prescriptions are not recommended when post-exertional symptoms are present (World Physiotherapy, 2021; NICE NG206, 2021). Chest pain, fainting, sudden severe breathlessness, new weakness or numbness on one side, or confusion need urgent care — call 911. Welltory is a general wellness product and does not diagnose, predict, monitor or treat any condition. Sources were retrieved on 21 October 2026.
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Written by Jane Smorodnikova
The founder and CEO of Welltory. A recognized tech leader with two Master's degrees and experience at MIT, she has scaled Welltory to over 17 million users.
Written by Tatsiana Yashyna
Deputy COO at Welltory. With a background in medicine and years of working with health data, she translates research and real physiological signals — sleep, stress, heart rate, and hormones — into clear, evidence-based explanations that help people understand what their bodies are telling them.
References
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- Welltory Help Center. How to take accurate heart rate variability measurements? https://help.welltory.com/en/articles/3361520-how-to-take-accurate-heart-rate-variability-measurements
