A few months ago I was sitting in a convention center about to deliver a keynote at an event, watching my Oura Ring throw up the same heart rate pattern it shows me when I’m at my Pilates class. Similar numbers, similar stress score. Except I was nervous, not fighting through the pulses of my leg raises.
That's when I realized why the two scenarios, although completely different, produce similar results. Your wearable doesn't know what you’re feeling. It just knows that your body is doing something and it's guessing what that is based on the signals your wearable is collecting, whether you're thrilled or terrified.
This doesn’t mean your tech is flawed. It’s a limitation baked into how every wearable on the market measures emotions and honestly, once you understand why, you’ll read your own data a lot differently.
Table of Contents
What Your Wearable Is Actually Measuring
Let's get one thing straight first. Neither the ring nor the watch nor the chest strap is measuring "stress" or "excitement". There is no such sensor. All the things it's measuring are the following physical signs:
Heart rate and heart rate variability (HRV)
Electrodermal activity, also known as skin conductance or galvanic skin response
Skin temperature
Respiratory rate (in case the device measures it)
All those are the consequences of work on your autonomic nervous system. Whenever you activate your sympathetic nervous system, your heart rate increases, heart rate variability decreases, you sweat a little bit, and your skin temperature changes. The process happens no matter whether you have to perform on stage, have a fight with somebody, or to see the letter with rejection on your laptop.
All that your sensor knows is the "sympathetic activation." That's all the information it has access to.
Stress and Valence and Why Your Ring Only Sees Half the Picture
Psychologists have divided emotions into two general dimensions. Arousal refers to your level of excitement. Low arousal means you're calm, while high arousal indicates being highly charged. Valence refers to whether the emotion is felt as pleasant or unpleasant.
For fear and excitement, their locations in terms of arousal are quite close to each other, as they're both high arousal emotions. The difference lies in their valence. But your wearable device can't pick that up because there's nothing you can wear that can tell whether you feel good or bad about the experience.
Basically, your device is the technological equivalent of the age-old Schachter-Singer two-factor theory, which proposes that your body gives you a rush of physiological arousal and then your brain will determine the emotional label based on the context. If it's a roller coaster, you'll feel excited. If it's turbulence in a plane, you'll be afraid. The same level of arousal, but with different labels, determined by your brain, not your body.
You're stuck where your body is before your brain makes its determination.
Real Examples Where This Actually Messes With Your Data
I've seen this play out in my own Oura and Ultrahuman data more times than I can count, and I hear the same thing from people using wearables all the time.
Pre-Race Nerves vs a Genuine Anxiety Spike
The HRV levels of runners preparing for a HYROX competition or a half-marathon will most likely plummet on the morning of a race. This is the same thing that happens when you're dreading a hard conversation with your boss. This is because your heart is going through the same preparation process regardless of what's about to happen.
Your smartwatch will alert you of the low readiness status without giving any information on whether you should expect it to harm your performance or it's just adrenaline making you ready for the race.
A Tough Workout vs a Genuinely Stressful Day
This is a very common mistake. An intense HIIT session and a terrible, stressful day at work can result in very similar elevated heart rate and decreased HRV.
WHOOP and Apple Watch will record strain for both types of activities. But strain from weight lifting and strain from three difficult meetings aren't the same for your recovery despite having the same picture on the graph.
Excitement Before a First Date vs Pre-interview Dread
Both of them come with butterflies in the stomach, sweaty hands, and a racing heart. No matter how cool the smart ring you have on may seem to be, it can't understand whether you're happy about the situation or not.
Why This Actually Matters Beyond Just Being a Fun Fact
This may sound like a minor detail at first, but it has very real consequences for data interpretation. Some apps have already begun labelling elevated arousal readings as “stress". And while I understand the temptation in terms of product design, this has the potential to confuse people.
If your app tells you you're stressed every single time you're simply excited, you begin to second guess feelings which should otherwise be totally normal.
I've heard stories from my colleagues who remember being overjoyed with a situation and their smart ring labeled it as “anxiety”. That's not a great place for a wellness product to put someone in.
This also has some practical consequences in terms of training implications. The treatment of pre-competition arousal as if it was chronic stress may lead to incorrect advice regarding deloading. You certainly don't need the same recovery after performing well in a race you were pumped for as you would if you had a terrible race day.
But you may need recovery after the whole week in which your nervous system was in fight or flight because of the actual stresses, unrelated to your training.
What Companies Are Actually Doing About This
For the record, this is far from being an unknown issue in the industry. So here are a few directions worth knowing about:
1. Context Stacking
Relying not only on the reading of the sensor, some platforms are adding additional information in terms of calendar events, self-reported mood logging, or even location to help interpret what has caused certain reactions that couldn't be easily identified only based on the sensor readings.
The daytime stress feature of Oura Ring relies partially on this approach, prompting users to log what they were doing before a sudden spike.
2. Facial and Vocal Cues, Where Applicable
Some companies developing smart glasses and earbuds are trying to integrate biometric signals with vocal tones and facial muscle activity, as they contain additional valence information.
3. Just Asking You
Quite simply, there's no substitute for a self-report at the moment. The best information is coming from the user tapping their mood status. While it's unattractive from a marketing perspective, it covers exactly that gap which can't be closed by sensors alone.
Unfortunately, none of these solves the problem yet. Valence is a difficult parameter to deduce from wrist or finger readings and I don't think we're getting a direct measurement of it anytime soon.
The Takeaway
While your wearable may accurately describe your body’s experience, it can't tell what your emotions really are. Your wearable will let you know when your nervous system has been triggered and it will always be accurate in doing so, but it will never be able to tell you why. It will also never be able to say anything about the quality of your experience.
So the next time your ring signals a surge and tags it with the label of stress, take a minute to pause and reflect. What were you actually going through? You may discover that what you were experiencing was actually excitement.