Learn to manage your chronic illness with a (Garmin) smartwatch, by Laure Wiggers, 2025/07.
A free, patient-written guide. Wiggers has had ME/CFS and POTS since 2009. Her idea: the ordinary smartwatch you already wear can be learned, slowly, into a way of reading your own body. Not an alarm, a notebook. She is explicit these are patterns to learn for yourself, not rules to apply, and that your Garmin can't warn you about everything.
Her own caution, up front: “be aware that your Garmin can't warn you about everything.”
This site takes her at her word. Wiggers asks readers to learn what is normal for their own body, and to decide for themselves whether her patterns are true for them. So that is what I do here: I run that exercise on four years of data, recorded before I had ever read her. I do it for myself, and as a worked example for others. It never grades her guide right or wrong; the only question is how much of it shows up in my body.
Reading four years of my own numbers needs a lens: some account of what these signals tend to mean for a body like mine. Hers is the one I chose. It was written by a patient, for patients, out of years spent reading the same family of watch I wear. It is free, in Dutch and English, with an audiobook. In the Netherlands it has standing: four of the most-visited Dutch patient organisations all point to it, and many people pace by it.
So using it as my lens is not only for me. Holding one real record, mine, against a guide that many people actually follow makes this a live example others can read too. I am not grading her map; I am seeing how much of it is drawn on my own body.
Where the guide is referenced
The Dutch ME/CVS Vereniging hosts the PDF directly; the Long COVID Toolkit recommends it for Garmin users; Post-COVID Nederland lists it among its tools; and MECVS Nederland recommends it as a guide made by and for people with lived experience. Internationally, the research forum Science for ME has an active thread on the English translation. The closest counterparts (Visible in the UK, MindfulPacer in Switzerland, the Workwell Foundation's clinical RHR + 15 rule) either need a dedicated device or are written for clinicians. In the patient-written, free, smartwatch-already-on-your-wrist category, Wiggers' guide is the one that exists.
Two things the watch reads, and how I read them
Her guide reads two different things off the same watch. One is the crash: the delayed bill you pay after doing too much, what doctors call post-exertional malaise, or PEM. The other is the body's moment-to-moment struggle with standing up, staying upright, blood volume and heat; this is the POTS side, the orthostatic side. Both show up in the same numbers, your heart rate, your stress, your HRV, and often on different days. These are the two things long COVID most often does that a watch can pick up: most people with long COVID report the crash, and trouble on standing is common too, though a formal POTS diagnosis fits a smaller share. Wiggers has both ME/CFS and POTS, so her guide teaches both.
This page holds her patterns against my own record, sorted by how my data can engage each one: the shapes I can recognize, the predictions I could test, and, for completeness, the parts my data cannot reach. The full statement-by-statement accounting lives in the ledger.
PEM, the crash axisLoad and recovery: doing too much, and the delayed crash that follows.
POTS, the orthostatic axisBlood volume and standing: the body's moment-to-moment circulation, not a crash.
Everyday triggersThe many ordinary things that spike a body: food, alcohol, hormones, light, noise, emotion.
She names a shape; the only question here is whether that shape is in my four years. When it is, I say how often, and when. These are descriptions, not crash tests.
Stuck stress, the wall of orange
PEM · POTS · everyday
A healthy body turns its stress system on for effort and off for rest. Sometimes mine gets stuck on: the Garmin stress bars stay orange all evening, long after I have stopped and lain down. Wiggers calls it a wall of orange.
morningmiddayafternooneveningnight
reststresshigh stress
The body lets go.
Stress rises to meet the afternoon, then the evening settles into rest. The autonomic system switches itself off.
Idealised Garmin stress level (0–100) through one day, 18 readings from morning to night. Not real data.
Day
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
A healthy evening
12
15
20
55
70
45
30
22
18
30
40
28
20
15
12
10
8
7
After overexertion
18
22
30
65
80
72
68
70
66
72
78
80
76
74
70
66
60
55
Idealised illustration of the pattern — not real data. Mirrors Wiggers pp. 30–36.
In my data?
Yes.
When, how often
It is one of the most familiar shapes in my record, scattered across all four years. Not a rare warning sign; an ordinary kind of day.
She is clear it has many causes, and my days bear that out: a heavy or late meal, an upsetting phone call, visitors, a hot bath, a poor night. Sometimes I can name the trigger; often the wall is just there and I cannot say why, which is exactly her point. I did also run the narrow crash test, does stuck stress come before a crash, and it came back weak: this is a read of why the body will not settle, not a crash alarm.
Once in a while my stress does the opposite of a wall: it sinks into a deep blue dip in the middle of the day, a U shape, while the body-battery gauge quietly drifts up. It looks like a patch of lovely recovery. Wiggers knows the shape well; for her it is the moment she feels suddenly drained and wiped, and she reads it as low blood volume and takes electrolytes.
morningmiddayevening
rest (blue)stressbody battery
Stress dips to blue, the battery drifts up.
It looks like the picture of recovery. But this is the moment Wiggers feels
suddenly drained and wiped, which she reads as low blood volume and treats
with electrolytes. I never did; yet the same shape sits in my data.
Idealised Garmin stress level and body battery (0–100) through one day, 16 readings from morning to evening. Not real data.
Reading
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Stress
46
54
60
58
44
28
18
14
16
24
40
56
62
60
54
48
Body battery
52
51
50
50
52
56
61
65
67
67
65
62
60
59
58
57
Idealised illustration of the pattern — not real data. Mirrors Wiggers pp. 36, 46.
In my data?
Yes.
When, how often
More common in my earlier years, fading in the later ones. But those later years are also when I started an antidepressant, so I cannot cleanly separate a real easing from the medication era; and I never took up her salt-and-fluid routine, so I cannot credit the fading to managing my circulation.
One honest limit: this is not a validated reading of POTS. POTS is defined by a heart-rate jump on standing that this watch has no sensor to see. So I call it the circulation pattern Wiggers names, present on my watch, and I leave the diagnosis aside. Like the wall of orange, I checked whether it flags a coming crash; it does not, which is exactly what you would expect from something that is not about crashes.
Here her guide makes a claim about cause and effect: this number moves, and a crash is coming. Those I can hold against my data. The verdicts are the scorecard's; the badge says how each one held up on my body.
A falling HRV, before a crash
PEM · crash axis
Showed up
Heart-rate variability, HRV, is the tiny variation in the gaps between heartbeats; more variation usually means a better-rested, more resilient body. Wiggers trusts it most: when it slides down over a few days, she reads a crash coming.
No HRV sensor on this watch — read sideways, through the night-to-night variability of sleep stress.
The morning looks perfect.
A sudden high reading reads like deep recovery — but after a big push it can be the body’s false calm, and the crash follows anyway. Wiggers calls it the parasympathetic swing.
Idealised nightly heart-rate variability relative to your normal in the nights before a crash (positive = above normal). Note the deceptive high the night before. Not real data.
Night
8 nights
7
6
5
4
3
2
1
crash
HRV vs. normal
0.2
-0.3
0.1
-0.2
0.3
-0.1
0.1
1.7
-0.4
Idealised illustration of the pattern — not real data.
This is the one that held up best, and the strangest to earn: my 2019 watch records no HRV at all, so I had to read it sideways, through the night-to-night jitter in my sleeping stress. Even so it cleared my pre-registered bar across the whole four years. Modest, and worth watching, not a forecast.
Body battery is Garmin's fuel gauge, refilling with rest, draining with effort. Wiggers names a trap in it: after you have badly overdone it, the watch can show a suspiciously high recovery overnight, a night that looks perfect, and a crash comes anyway. She calls it the parasympathetic swing.
☾
0%
A healthy night refills the battery.
You spend the day, you sleep, and the overnight recharge brings you back near full. The morning starts with reserves.
Idealised body-battery level the morning after, for two kinds of night. Not real data.
Night
Overnight level (%)
A healthy night
88
A deficit night
24
Idealised illustration of the concept — not real data. How it actually looks in my body is the thread below.
Partly, and the split is the finding. The reassuring number a normal user would trust, a high morning battery, did not separate crashes from ordinary days. But the deeper reading underneath it, a collapse in that night-to-night jitter, held up. The body's warning is real; the watch face just shows it as good news.
The most famous pacing rule there is: if your resting heart rate in the morning is up a handful of beats over your personal normal, you overdid it, so take it easy today.
It settles back.
Heart rate rises to meet the activity, then drops back to your normal within minutes. The engine idles down.
Idealised heart rate (bpm) through one day, 12 readings from morning to evening; resting baseline about 60 bpm. Not real data.
Day
1
2
3
4
5
6
7
8
9
10
11
12
A normal afternoon
60
61
64
78
95
88
70
63
61
60
60
59
After overdoing it
62
66
80
98
100
99
97
95
92
88
84
80
Idealised illustration of the pattern — not real data.
On my body, mostly it just is not there: no clean rise in resting heart rate before my crashes. An honest negative for the best-known rule in pacing.
Her steps-and-activity rule: there is a personal line above which you pay for it, and you have to respect the lag, the exertion that crashes you is in the days before, not the same day.
The bill comes days later.
Above your personal line, crash risk climbs — but the crash rarely lands the same day. The exertion that costs you is usually a few days back.
Idealised daily exertion across one week (personal threshold = 7); the over-threshold day is Tue, and the crash follows about four days later on Sat. Not real data.
Day
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Exertion
3
9
4
3
2
2
3
Idealised illustration of the pattern — not real data.
I thought this was my clearest tell. It turned out to be an artifact of how the baseline was calculated: once I fixed that, the signal vanished. An honest correction, on the board of things that did not survive.
She says a stress score of 40 is far more tiring than a 30: a small step on the chart that is a big step in the body, a kind of stair-step.
Held, with a twist. How I felt does not move in a straight line with the stress number; the relationship bends. That bend is real enough that a naive straight-line reading of it looks flat and misses it.
A living scorecard has a fourth state I don't hide: patterns from her guide that my data could check, that I simply haven't run yet. Here are the ones a reader is most likely to have met in her guide; the full list is in the ledger.
Whether I sleep longer than usual in a crashPEM · crash axis
Whether uneven bedtimes cost me the next dayPEM · crash axis
A home-built sleep-quality score, from the stages this watch does recordPEM · crash axis
Whether living above a 70 to 80% body-battery floor means fewer crashesPEM · crash axis
Whether a high-stress day really costs the next night's rechargePEM · crash axis
Whether faster breathing marks a body that stays switched onPEM · POTS
For completeness, so a curious reader who has read her guide is not left wondering: the patterns I can only point at. Either I never tracked the input, or this watch is blind to it. Not tested, just honestly flagged.
Managing POTS with salt, fluids, electrolytes and compression lowers your daytime stress.
POTS · orthostaticI never did any of it: no compression, no salt-loading, no extra fluids. There is no intervention in my passive record to measure; showing it works would take a trial where I actually do the management.
The heart races on standing up, the NASA-lean jump that helps define POTS.
POTS · orthostaticThis watch records no posture. It cannot tell a stand-up heart-rate jump from any other rise.
Blood oxygen drops after standing or moving, and rises again lying down.
POTS · orthostaticPositional, and Wiggers flags the watch's blood-oxygen reading as unreliable anyway.
Low or dropping air pressure leaves you dizzy and wiped.
POTS · everydayNot a Garmin health metric; it needs an outside weather source joined in.
Skin temperature shifts around a crash, mostly up.
PEM · crash axisNo temperature sensor on the Forerunner 245.
The Garmin sleep score predicts the next day's capacity.
PEM · crash axisGarmin's own score is proprietary and leans on REM the Forerunner 245 doesn't record, so I can't reproduce that number. A home-built proxy from the stages I do have is a different thing, and it is on the list above.
The everyday triggers I know but never logged
Her guide also lists the everyday things that spike a body: food, alcohol, hormones, light, noise, emotion. Some of these I recognize in myself, strongly. Alcohol: I stopped when I got ill; it makes me really tired, not worth the extra strain. Light: my sunglasses are one of the standard things I bring whenever I leave the house. Noise: headphones on, and on some days I have to shield hard against leaf blowers, traffic, a vacuum cleaner. But I never logged any of it, so here it stays anecdote, not something I can hold against data. The one everyday trigger I do chase, with the data I have, is emotional load, over on Beyond the guide .
What holding it to my data showed
The shape that held up best was a slow one, on the crash side: the night-to-night jitter in my sleeping stress. Most of the famous rules, the morning heart rate, the four-day build-up, were honest negatives for my body. The orthostatic side is real but quiet, and mostly my watch cannot see it.
None of it predicts a crash. At best it is a weather report on the body, a sense of the kind of week I am in. And it is one body's read, mine, which may not be yours.