For yourself
Available from 15 May 2026An instrument to support your own exploration — how your daily life affects you, how your body responds, and what works for you and what doesn't.
The StressChecker is a browser application that measures your heartbeat and heart rate variability and translates them into a single readable value: the Relax Index. An honest measurement — ninety seconds, at a moment you choose yourself — and you get to know your own patterns. What you do with those observations remains up to you. Three books provide the framework of thought: how to shape a life that fits who you truly want to be — not driven by obligation, but from your own considered choices.
In use since 2010 by individuals, coaches and health professionals — now fully reworked as a browser app.
The StressChecker measures the activity of your autonomic nervous system — the system that unconsciously regulates your tension and recovery. It combines two signals that together give a practical picture: your heartbeat (activation) and your heart rate variability (recovery). Both are brought together in a single readable value: the Relax Index.
The value of the StressChecker doesn't lie in any one measurement. It emerges from regular measuring — under comparable conditions, at your own pace — so that you get to know your own patterns. What strains you? What helps with recovery? How does that change over time?
A single measurement on its own says little. It becomes valuable when you can compare it — with how you feel, with earlier measurements, with what was going on this week. The StressChecker makes that possible in one instrument you use daily.
The StressChecker offers three ways to measure — for different moments and different purposes.
90 seconds
Your daily measurement. At rest, at a fixed time — first thing in the morning, for instance. Gives you your Relax Index plus personal feedback. Those who do this consistently recognise patterns across weeks and months.
90 seconds
A measurement in a specific situation. Before an important conversation, after work, after exercise. By comparing situations — the same one over time, or different ones side by side — you see how your body responds in particular moments, and what changes after rest, exercise or different circumstances.
3 to 5 minutes
An active session in which you practise with your breathing. You see in real time how your heartbeat responds. A practical way to experience what relaxation does for you — and how you can call it up yourself.
Not just a number — a readable story about what your body is showing you.
A clear value on a scale from 0 to 10, based on the combination of your heartbeat and heart rate variability. Not abstract figures — a directly readable indicator.
After every measurement you receive a short, personal reflection. What stands out? What does this measurement say in connection with your self-assessment and earlier measurements?
Before every measurement you answer a few short questions: how relaxed you feel, how vital, and what's on your mind. That way every measurement gets context — not just a number.
Your own assessment is shown next to the objective measurement. Sometimes they match, sometimes they don't — and it's precisely that difference that's instructive.
A measurement is more than an outcome. It is an interruption of what you were doing — an act with which you mark for yourself: now I am looking at what my body is saying. Ninety seconds in which nothing else has to happen.
That's why the StressChecker works with a physical heart-rate monitor via USB or Bluetooth — and not with your phone's camera. Putting on the sensor, sitting still, the moment of starting: that's part of the measurement. Not because a camera-based measurement would be technically impossible — modern algorithms can do that reasonably well by now. But because the ritual itself is part of what we offer. A moment you choose, not a feature you switch on in passing.
For those who follow their body daily and want to get to know their patterns, that's the difference between a measurement that drifts along with the flow of the day, and one that stands out within it.
Measure → Compare → Recognise patterns → Adjust
Attach your heart-rate monitor, answer a few short questions and measure for 90 seconds. Best at a fixed time — first thing in the morning at rest, for instance.
You see your Relax Index and how it relates to your self-assessment and earlier measurements. With personal feedback alongside.
After a few weeks of consistent measuring, trends become visible. Which days, which situations, which routines make a difference?
Try what works for you: more rest, different breathing, different routines. See the effect in your measurements.
A heart-rate monitor and a device with a browser. No installation, no extra software.
Which heart-rate monitor suits you? The USB heart-rate monitor is wired and works during measurement without a wireless connection — a safe choice for those who prefer to avoid Bluetooth signals. The Bluetooth heart-rate monitor is wireless and more comfortable in daily use — and the only option for tablet or smartphone.
For iPhone and iPad users: download the free Bluefy browser from the App Store. Safari does not support Bluetooth heart-rate monitors; Bluefy does.
Order your StressChecker annual subscription and, if you don't already have one, your heart-rate monitor — all in one step in the shop.
We could have built an iOS or Android app. We deliberately chose not to — and instead made a browser app that runs in any browser. Here's why that's an advantage for you.
To be honest: an internet connection is needed to measure — a native app could do this offline. In practice this isn't a barrier: you usually measure at home or at work, where Wi-Fi or mobile network is available. For data synchronisation with your personal account, a connection is needed anyway.
One measurement is a snapshot. Ten measurements tell a story. Thirty show you your own rhythm. The StressChecker is built for the story, not for the isolated moment.
See how your average Relax Index develops across weeks. Rising, falling, stable — and when changes occur.
What was going on around striking measurements? The context you provide beforehand reveals which themes recur — work, sleep, relationships.
Based on your measurements you receive targeted questions that help you see connections. No off-the-shelf advice — invitations to reflect.
Since 2010 the StressChecker has been used and discussed in independent media and by professionals. The quotes below concern the measurement method, which also forms the basis of the new browser app.
German health magazine, 2012
Readers tested the StressChecker and described how measurements sometimes turn out differently from gut feeling — and that this is precisely what creates awareness.
"The result was different from how it felt. It makes stress sensitivity very conscious."
Independent German review, 2018
An extensive review describes the StressChecker as a practical tool for making the connections between strain, relaxation and recovery visible — through regular comparison over time.
"Measure regularly, compare, learn what relaxation truly does."
Dutch psychologist and epidemiologist
Dr Lippens describes the StressChecker as a way to recognise signals in time and to make the influence of lifestyle and relaxation visible.
"A simple way to gain insight into the influence of lifestyle and relaxation."
We show only independent sources and short quotes here. Full articles remain with the original publishers.
The StressChecker measures your heartbeat and heart rate variability (HRV). Both are brought together in a single readable value: the Relax Index. HRV is never interpreted as a standalone "score" — it's always about the combination of activation and recovery.
For self-knowledge, two to four basic measurements a week often suffices. More important than frequency is consistency: measure under comparable conditions, at a fixed time, so that you can compare honestly.
In addition you can broaden your self-knowledge with biofeedback sessions and situational measurements. Biofeedback lets you experience how you can influence your own recovery; situational measurements show how different circumstances — before or after a conversation, after exercise, in a busy week — affect your body.
The StressChecker is an annual subscription: €69 per year. For professionals (coaches, therapists) there is StressChecker Pro in three sizes — fitting practice size: from €99 per year (S, up to 10 clients) to €299 per year (L, up to 75 clients). The heart-rate monitor is a one-time purchase (€37.50 for USB, €49.50 for Bluetooth) — it is not included in the subscription.
Want sensor and software in one package? The StressChecker Complete package offers a Bluetooth heart-rate monitor plus 12 months' subscription for €99 — saving you €19.50 compared to buying separately.
Yes. The StressChecker is a browser application and works on all modern devices. On Windows and Mac you can use either heart-rate monitor; on Android and iOS only the Bluetooth one. iPhone users use the free Bluefy browser; all other devices use Chrome, Edge or Firefox.
Yes, the StressChecker works online. The measurement itself takes 90 seconds; the internet connection is needed to securely save your measurements and deliver your feedback.
Your measurement results are yours. Lifestyle Monitors stores them to make them useful for you — as memory, as comparison material, as a source of insight — not because they're ours.
What that means in practice: you can view, export and delete them, and decide who has access. Working with a coach or therapist who uses StressChecker Pro? Then things like deleting or unlinking happen, where relevant, in agreement with them — your client file is often a working document for the professional, with decisions tied to it.
Yes. Many coaches and therapists use StressChecker Pro with their clients. If your coach uses StressChecker Pro, you can link your measurements to their account — your home measurements then appear directly in their dashboard.
Wearables deliver a lot of data, but little interpretation. The StressChecker is made for one short, consistent measurement a day, with a readable value and context. Moreover, a dedicated heart-rate monitor is more accurate than a wristwatch — especially for the fine variation between heartbeats, which is needed for the Relax Index.
Yes. At app.stresschecker.com you can start a demo without a heart-rate monitor to get to know the application.
The StressChecker is not a medical device. It does not diagnose and does not replace a medical professional. The Relax Index and the zones are practical signals for self-reflection and awareness, not clinical statements.
For persistent symptoms — exhaustion, sleep problems, low mood — we recommend consulting your GP or therapist.
An annual subscription gives you access to all features. The heart-rate monitor is a one-time purchase — if you don't already have one.
Heart-rate monitor sold separately: USB €37.50 or Bluetooth €49.50
The StressChecker Complete package includes a Bluetooth heart-rate monitor plus 12 months' subscription for €99 — everything in one.
View Complete package →Coaches, therapists, occupational physicians and lifestyle professionals use StressChecker Pro: client management, dashboard, integration with home measurements and weekly reports. Three sizes — to fit your practice:
up to 10 active clients
€99 / year
up to 25 active clients
€199 / year
up to 75 active clients
€299 / year
The Columbus Catalyst Code is the overarching vision from which Lifestyle Monitors emerged: a contemporary framework about how behaviour, identity and body interconnect, and how lasting change emerges from who someone truly wants to be — not from compulsion or willpower alone.
Three books work out that framework. The instruments — StressChecker and Healthy Lifestyle Monitor — bring it into daily practice. Those who want to understand the connection will find the starting point here.
More about the Columbus Catalyst Code →