Pacing without buying new gear: how to track your energy envelope with ME/CFS or Long COVID

Short answer

You can start pacing with ME/CFS or Long COVID without buying a new device. The core of pacing is a written record of what you did and how you felt 24–48 hours later, plus a simple margin such as the 50% rule. A phone camera can add a morning heart rate and HRV spot reading, and a watch you already own can show your resting heart rate trend. What none of these gives you is a live alarm while you are in the middle of a task — that is the one job a worn heart rate monitor with alerts does, and it is worth buying only if your crashes come from physical effort you do not notice at the time.

If shopping for a tracker feels like one more thing you do not have the energy for, that is not weakness or a lack of commitment. With post-exertional malaise the cost of effort arrives late, and choosing, setting up and charging a gadget is effort too. Before you blame yourself for not "doing pacing properly", check what your body already recorded — in a notebook, on your phone or on a watch you already wear.

Note: this article is for education and is not medical advice. Pacing is a self-management approach, not a cure for ME/CFS or Long COVID. Any heart rate ceiling is an estimate to agree with your clinician, especially if you take medicines that change heart rate, faint, or have a heart rhythm problem. This guide is published by Welltory, which makes one of the apps mentioned; other tools are described from their own help pages.

You don't have to work this out alone.

Welltory runs Energy Lab, a paid, moderated online community for women aged 18 to 65 living with ME/CFS, Long COVID and other energy-limiting conditions, where members learn to read their own diary, heart rate and HRV 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

Can you start pacing without a heart rate monitor?

Yes. Pacing is a way of managing activity, not a piece of equipment. The UK's National Institute for Health and Care Excellence (NICE) defines energy management in its ME/CFS guideline as managing activities to stay within your energy limit, and describes post-exertional malaise (PEM) as symptoms that can "typically worsen 12 to 48 hours after activity". The tools follow from that delay: you need a way to connect today's symptoms with what you did one or two days ago, and a way to leave yourself a margin.

NICE also asks clinicians to make self-monitoring of activity as easy as possible and to use tools the person already has, such as an activity tracker, a phone heart rate monitor or a diary. That is the spirit of this article. The best tool is the one you will still be using in three weeks, on a bad day, without help.

There is a second reason not to rush into buying. In a 2026 randomised controlled trial in Nature Communications, 250 adults with Long COVID used either a pacing app with a Fitbit that sent alerts at 50%, 75% and 100% of a personalised activity limit, or 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. That does not mean devices are useless — many people find alerts genuinely helpful — but it does mean the gadget is not the active ingredient. The habits are.

If you are new to the idea, our complete guide to pacing with chronic illness compares every approach. This article answers a narrower question: how to start, and keep going, with what is already in your home.

What do you already own that can help you pace?

Most people reading this already have three or four pacing tools. The question is which job each one can do. Here is an honest map.

Read the table by the third column. Only something worn continuously can tell you, in the moment, that you have crossed a heart rate ceiling. Everything else works after the fact — which, with a delayed illness, is where most of the useful information is anyway. Our article on why you can crash with zero steps explains why step counts in particular can look harmless before a crash: thinking, emotion, noise, heat and standing barely register as steps.

How do you find your energy envelope with just a notebook?

The energy envelope is the amount of physical, mental and emotional activity you can do without triggering a crash. You find it from a record, not from how you feel at 11 a.m. on a good day. A notebook does this well.

Start with four fields. Our activity and symptom diary guide goes through them in detail; the short version is:

• Morning: a number out of 10 for how much you have today, before you get up.

• What I did: three to six short items with rough durations — including calls, screens, appointments and time standing.

• How I felt: one line and your worst symptom out of 10.

• The 24–48 hour column: two days later, on the same line, write "better", "same" or "worse".

The last column is the one that makes it a pacing tool. Without it you have a mood log. With it, after two or three weeks, you can usually see which kinds of day are followed by worse days, and how many hours later the cost arrives. That is your envelope, drawn from your own life.

Add a margin. Many people use the 50% rule: plan to do about half of what you feel able to do, and stop before you feel tired. Patient-organisation guidance such as Emerge Australia's pacing fact sheet puts it in almost those words. It is a rule of thumb, not a validated threshold — no trial has shown that 50% is the right number — but it buys back the time PEM takes to show up. If half sounds impossible, start with "stop before the point where I usually push through".

Write on the day, not on Sunday. Reconstructing a week in one sitting produces a tidier record that is less true. And use the same scale every time: your 4 only means something next to your other 4s.

Keep it cheap. If writing is hard on your hands or eyes, use voice notes, a printed grid with tick boxes, or a sticker on the calendar for "crash day". The format matters far less than the 24–48 hour look-back.

How do you use your phone for a morning heart rate and HRV check?

Your phone camera can take a short heart rate and heart rate variability (HRV) reading. You rest a fingertip over the camera and flash and keep still; the app reads tiny colour changes in the skin as blood pulses through it. This method is called photoplethysmography (PPG). For pacing, its most useful form is a morning check: one reading, taken the same way each day, compared with your own recent average.

What it can tell you. Several lower-than-usual HRV mornings, or a higher resting heart rate, after a busy day can be a reason to plan a lighter one. Read alongside your 24–48 hour diary column, it can help you see the cost of a day that felt fine at the time. Our guide to morning HRV pacing covers how to read it next to how you feel; for ME/CFS specifically, why general heart rate and HRV norms don't fit explains why the only useful comparison is with yourself.

What it cannot do — said plainly. A camera reading is a snapshot at rest. It is not 24/7 tracking. It cannot follow your pulse while you cook, shower or climb stairs, and it cannot warn you in the moment that you have crossed a ceiling. It is not an ECG and cannot replace one. Welltory's help center also notes that camera readings lose accuracy with movement and are unreliable for people with arrhythmias.

How accurate is it at rest? In a 2017 study of 29 healthy adults measured lying still for five minutes, a smartphone camera app's HRV agreed closely with ECG, with a technical error of about 6%. That was a different app, in healthy people, at rest. Our article on how accurate HRV from a phone camera is goes through the evidence and its limits.

Make it cost as little as possible:

• Same time, same position. Soon after waking, before coffee, food or a shower. Lying down is fine, and often better with orthostatic symptoms.

• Breathe normally. Slow, deep breathing during the reading inflates HRV.

• Give it one to two weeks before you read meaning into it. Until then, the numbers are data points, not a trend.

• Skip it on a bad morning if it costs too much. A gap in the data is better than a crash caused by the routine.

A camera-based morning check is not unique to any one company. Visible's free app, for example, uses the phone camera for its morning check-in and Stability Score; its heart rate zones and PacePoints need the paid membership and its band. Welltory also takes camera readings. Whichever you use, the job is the same: one comparable number a day, read beside your diary.

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What can the watch you already own do for pacing?

If you already wear an Apple Watch, a Garmin, a Fitbit, a Samsung or a Pixel watch, you may have more of a pacing tool than you think — and also less than the marketing suggests. Before you buy anything, check three things on the device you have.

1. Your resting heart rate trend. Almost every watch records a daily resting heart rate. A rise over your own usual after a busy day, or a slow drift up over a week, is useful information, and it costs you nothing extra. Read it as a trend, beside your diary.

2. Whether its heart rate alert fires while you are active. This is the detail most people miss. Apple's support guide says Apple Watch high heart rate notifications fire when your heart rate stays above a chosen threshold "after you've been inactive for at least 10 minutes". Garmin's manual for the Venu 3 says its abnormal heart rate alert works "after at least ten minutes of inactivity". Those alerts are designed to flag an unusually high pulse at rest. They will not reliably tap you on the wrist halfway through carrying laundry upstairs, which is the moment a pacing alarm is meant for. Other brands differ; check your own manual for the words "inactive" or "at rest".

3. Whether it has workout heart rate alerts. Many watches can alert you to heart rate during a recorded workout. On Apple Watch, the Workout app lets you add a heart rate alert to a workout, for example when your heart rate leaves a set range. Some people with energy-limiting conditions start a workout on the watch before a known heavy task — a shower, a supermarket trip, a hospital appointment — so that the alert is live for that stretch. It drains the battery and only covers the tasks you remember to start it for, but it uses hardware you already own.

A note on accuracy. Optical sensors on the wrist are least accurate during movement, which is exactly when a pacing alert matters. A 2020 analysis in npj Digital Medicine found absolute error during activity was on average 30% higher than at rest. For a resting trend, a wrist watch is usually fine; for a precise live ceiling, a chest strap is more reliable.

If your watch also syncs HRV, the morning reading can come from the watch instead of the camera. Pick one source and stay with it — mixing sources makes the trend harder to read.

When is a heart rate monitor with alerts actually worth it?

A worn heart rate monitor with an alarm does one job nothing else on this list can do: it tells you, while you are doing something, that your pulse has crossed the ceiling you set. That is the core of heart rate pacing, and for some people it is the tool that finally makes the line visible. For others it adds cost, charging and anxiety without changing much.

It is more likely to be worth it if:

• your diary shows crashes after physical tasks that felt fine at the time — housework, a walk, standing at an event;

• standing up makes your heart race, and you suspect upright time is part of the cost (a clinician can check for orthostatic intolerance or POTS);

• you have already kept a diary for a few weeks and want to test a specific question, such as "does a shower take me over my ceiling?";

• the watch you own cannot alert you during activity, and you have tried the workout-alert workaround and found it too fiddly.

It is less likely to change much if:

• your crashes mostly follow thinking, emotional or sensory load — a long call, a difficult conversation, a noisy room — which can barely move your pulse;

• you are severely affected and mostly lying down, where the morning check and a diary may tell you more;

• numbers make you anxious or push you to check them all day.

What the research says. The evidence is real but small. In a 2023 international survey of 488 people with ME/CFS who paced with a heart rate monitor, respondents reported more than 30 benefits and more than 30 drawbacks, and used more than 100 different devices. A 2025 feasibility study of heart-rate-guided pacing in 47 people with ME/CFS or Long COVID suggested it is workable, but it was not designed to prove effect. And in the 2026 Long COVID trial above, activity alerts did not reduce PEM more than a simpler app. The honest summary: alerts can help some people, they are not proven to prevent crashes, and they work best on top of a diary, not instead of one.

If you do buy one, a common starting ceiling from the Workwell Foundation is your waking resting heart rate averaged over a week plus 15 beats per minute, with the advice to avoid more than about two minutes above it. Treat that as an estimate to agree with your clinician. Our comparison of the best pacing apps shows what each tool measures, and our breakdown of what pacing apps cost, and which hardware each one needs puts the one-year and three-year cost side by side. If you are weighing any new device at all, start with our guide to whether you need a new wearable.

How do you keep tracking from costing you energy?

Tracking is an activity. Attention, screen time and decisions come out of the same budget as everything else. A tracking routine that costs more than it gives is not pacing; it is one more drain.

Track in seasons, not forever. Use the diary closely for two or three weeks when you are finding your envelope, after a crash, or when something changes — a new medicine, a new job, the start of winter. Then step back to the minimum: the morning number and a crash note.

Let defaults do the work. Step count, resting heart rate and sleep from a phone or watch you already have are recorded in the background. You do not need to look at them daily. Look at them when the diary tells you a crash happened, and look back two days.

Have a crash-day version. On a bad day, the whole entry can be one word: "crash". Fill in the rest later, or not at all. Gaps are normal.

Let someone else hold the pen. A partner, friend or carer can write the "what I did" column or read you the morning question. That is a legitimate pacing adjustment, not a failure.

Avoid the "good morning" trap. A good reading or a good-feeling morning is exactly where boom and bust starts. Use a good day to stay inside the envelope, not to catch up. And remember that a good-looking number in the middle of a crash can mislead, which we cover in when a good HRV reading is not good news.

Before you blame yourself, check what your body already recorded

When pacing does not seem to work, the thought that comes is often "I'm doing it wrong" or "I need better equipment". Usually neither is true.

What usually happened is visible in hindsight, even without a new device. A supermarket trip on Tuesday, a "worse" in Thursday's column. A resting heart rate on your old watch a few beats higher than usual the morning after an appointment. Two short nights before the day you crashed. Your body recorded the cost; you just had not lined the records up yet.

You are not failing at pacing because you do not own a heart rate monitor. You are learning a limit that moves and cannot be felt in real time. Change one thing — a rest after every appointment, a seated shower, a lower plan on the day after a big one — and watch your 24–48 hour column for one to two weeks. If the pattern points at physical effort you cannot feel, that is the point at which a worn alarm becomes worth considering.

Living with pacing on a small energy budget: the questions people ask next

Is pacing with a diary as good as pacing with a heart rate monitor?

They answer different questions, so neither replaces the other. A diary with a 24–48 hour column shows which kinds of day are followed by worse days, which is the core of finding your energy envelope; a heart rate monitor with alerts shows when you cross a ceiling during a task. Research on both is small, and a 2026 randomised trial in 250 adults with Long COVID found that activity alerts did not reduce post-exertional malaise more than an app without tracking. Many people start with the diary and add a monitor only if the diary points at physical effort they cannot feel.

Can I pace ME/CFS with just my phone?

You can do a lot with just a phone. It can hold your diary, count steps in the background if you carry it, and take a morning heart rate and HRV spot reading with the camera, which you compare with your own average. What a phone alone cannot do is watch your heart rate through the day or alert you while you are active, so it cannot tell you in the moment that you are over a ceiling. For many people with ME/CFS, phone plus diary is a reasonable start.

My watch's high heart rate alert never goes off when I'm active. Is it broken?

Probably not. On Apple Watch, high heart rate notifications fire when your heart rate stays above your threshold after you have been inactive for at least 10 minutes, and Garmin's abnormal heart rate alert also works after at least ten minutes of inactivity. They are designed to flag a high pulse at rest, not to act as a pacing alarm. Many watches can alert you during a recorded workout instead; check your own manual for the details.

I'm severely affected and mostly in bed. Is any of this worth the effort?

Only the parts that cost less than they give. For people who are severely affected, even writing can be a load. The smallest version is a morning number out of 10 and a one-word note on crash days, kept by you or by someone who helps you. A phone reading lying down is optional. Upright time, noise, light and conversation often matter more than steps, so a carer noting those can be more useful than any device. Your clinician should help set priorities.

Do I need a chest strap, or is my wrist watch enough?

For a resting heart rate trend, a wrist watch is usually enough. For a live heart rate ceiling during movement, a chest strap is more precise: optical wrist sensors are least accurate during activity, which is when a pacing alert matters. Chest straps can be uncomfortable to wear all day, especially with chest-wall pain or sensory sensitivity, and many people use one only for known heavy tasks. If you already own a watch, try it first before buying a strap.

How long before my diary shows a pattern?

Usually two to three weeks of consistent entries, sometimes longer. Post-exertional malaise typically worsens 12 to 48 hours after activity, so each "big day" needs two days of follow-up before it means anything, and patterns need several examples. Morning heart rate and HRV readings also need one to two weeks before an app can compare them with your own baseline. Gaps on bad days are expected; keep going with the minimum rather than stopping.

How to bring this up with your doctor

You do not need a gadget to be taken seriously. A few weeks of a simple diary can make a short appointment go much further.

Lead with function. "Before I got ill I worked full time. Now a supermarket trip puts me in bed for two days." That describes post-exertional malaise more clearly than any chart.

Bring one page. Your main problem in one line; what you could do before and what you can do now; your crash pattern from the diary (what sets it off, how many hours later, how long it lasts); and, if you have them, a few weeks of morning heart rate or resting heart rate with crash days marked.

Ask about PEM directly. Ask whether your symptoms fit post-exertional malaise and whether it has been screened for, for example with the DePaul Symptom Questionnaire PEM subscale.

Ask whether a heart rate ceiling makes sense for you. Especially if standing makes your heart race, you faint, you have a known heart rhythm problem, or you take medicines such as beta-blockers or ivabradine that change heart rate. Ask how to set or reset the ceiling.

Ask about orthostatic symptoms. If your diary shows that showers, queues or cooking are expensive, ask whether an active stand test or a tilt-table test is appropriate.

Say what you are not asking for. "I'm not asking you to read my app or recommend a device. I'm showing you that my days after appointments are consistently worse."

Know what needs urgent care. Chest pain, fainting, sudden severe breathlessness, new weakness or numbness on one side, or confusion need urgent care — call 911 — whatever any number shows.

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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 ME/CFS, Long COVID, post-exertional malaise or any other condition. It cannot tell you your energy limit, and it is not a live heart rate alarm: a phone camera reading is a spot reading, not 24/7 tracking. What it can do is keep a steady record of a morning signal next to your own notes, using the phone you already have.

1. Take a morning reading with the phone you own. Put your fingertip over the camera and flash and keep still. Camera readings work on iPhone X and later and on many modern Samsung phones; some phones, including Google Pixel 6 to 7 Pro, are not supported. If you already own a compatible chest strap such as a Polar H10, or an Apple Watch, Samsung Watch or Google Pixel Watch (series 2, 3 and later), the reading can come from there instead. Measure after waking, in the same position each day; Welltory needs a week or two of regular morning readings to form your personal baseline.

2. Know what the free version keeps. After the trial, the free version still allows one HRV measurement a day, with five core indexes, which is enough for a morning check. Data older than 30 days is deleted on the free version, so export it if you want a longer record. Our guide to what Welltory includes for free has the details.

3. Log a crash in Crash Tracker. On iPhone, Welltory offers Crash Tracker — available to new users who report Long COVID, ME/CFS or POTS during onboarding now, and to all iOS users from November 2026: you record when a crash began and ended, its severity, symptoms, what came before and what helped. Logging is free. With a subscription and at least 14 reliable days of data, it shows your activity, stress time and HRV against your own baseline around each crash. "What came before" is context, not proof of a cause.

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 tag, type or talk: "long call", "shower", "appointment", "period day 1", "short night". With camera-only readings you can still add a note in your Journal at any time.

5. Let My Patterns collect the context. With a watch or ring and regular tagging, 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 and tags that are rare but hit hard.

6. Build a personal log for your doctor or appointment. Journal keeps measurements, tags and notes together. From the Welltory web app you can export a CSV (Dashboard → choose a chart → Export) to sit next to your paper diary on 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. Working out your envelope while you are ill is hard, and most people do it alone. Energy Lab is Welltory's paid, moderated online community for women aged 18 to 65 living with energy-limiting conditions such as ME/CFS, Long COVID, POTS and fibromyalgia. You keep your own records — a notebook, a phone, a watch — and the Lab is where members learn to read them 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.

A note for Black Friday: from November 25 to December 1, 2026, Welltory users can use the code WelltoryBF40 at checkout for a special Black Friday discount on Welltory Premium. Premium is billed annually and renews automatically until you cancel, and the checkout page shows the final price before you pay. See the Black Friday offer

How we made it

Made with AI tools, then edited and fact-checked by the Welltory team. See our Editorial & AI policy. Device features were checked on the manufacturers' support pages on October 22, 2026.

Jane Smorodnikova, co-founder of Welltory, built the methodology behind how we read physiological data.

Written by Tatsiana Yashyna.