Millions of people use a wearable health and fitness tracker. These devices can be useful for monitoring activity levels, sleep quality and heart rate. But for some, wearables can have unintended consequences on wellbeing.
This is something I encountered recently. At a public talk, I got to chatting with a man who told me a story that stayed with me.
He’d just finished a long hike and felt great. Then he glanced at his smartwatch. Heart rate: 130 bpm. Instant panic.
About 30 minutes later he realised the cause: the altitude. Yet in that moment, he’d gone from feeling perfectly fine to feeling awful – all because of the smartwatch’s reading.
This man isn’t alone. Some users have found their wearable increased anxiety so much they needed to stop wearing it.
A key reason wearable health devices may increase anxiety for some people comes down to a mismatch in expectation and what the device says.
Our brain is a prediction machine. It continuously, automatically generates and updates a mental model of our environment by comparing its predictions to the sensory information it receives.
Processing every sensory input from scratch would be slow and inefficient. By predicting what it expects to encounter, the brain can interpret noisy sensory information quickly and usually accurately.
Some examples of this happening include feeling your phone vibrate when you’re expecting an important message – only to discover it never rang at all. Or being abel ot raed tihs snetnece despite the typos, because your brain predicts what should be there.
The same principle applies to our bodily states. Our brains don’t simply read bodily states, they predict them.
We move through the day with an internal model of what our body “should” be doing: roughly what our pulse, temperature and breathing typically feels like when we’re calm, active or nervous.
When sensory information arrives that doesn’t match those expectations – such as having a higher heart rate – the brain generates a “prediction error”. This alerts us that the sensory information does not meet our expectations.
Most prediction errors are trivial and simply a mismatch between expectation and incoming information. The brain often resolves these errors automatically by updating its model and adjusting its predictions.
Since this process usually happens automatically, we typically don’t notice it. But if it does reach the level of our conscious awareness, we may search for an explanation for why our expectations and experience differ.
So if your heart rate feels faster than expected, you may link this to the fact that you drank too much coffee. Because we expect our bodily sensations to vary throughout the day, such explanations may be enough to prevent us becoming concerned by the prediction error.
The same thing can happen when we get a wearable reading that goes against expectation. However, because smartwatch readings appear clear and objective, we may place greater weight on them and may not dismiss an unexpected reading as readily. Even if you feel perfectly fine, seeing an elevated heart rate on your smartwatch may make you think something is wrong and kick off a cycle of worry.
My research suggests this may particularly be a concern in people prone to anxiety, who already tend to pay close attention to their internal bodily signals.
Research my colleagues and I conducted during COVID also found the more anxious a person was generally, the more likely they were to monitor their bodily states through objective measures (such as taking their temperature).
This behaviour in people with anxiety is unsurprising. Hypervigilance towards the body can feel protective, a way to spot problems early and reduce uncertainty. But it can quickly lead to a cycle of worry and seeking reassurance.
When such safety-seeking behaviour is reduced through therapy, anxiety symptoms tend to ease – at least partly because people are less hyper-focused on their bodies.
Yet the relationship can go both ways. In that same COVID study, we found a bi-directional link between anxiety and attention to bodily signals. Paying more attention to bodily states increased anxiety, and anxiety increased attention to bodily states – a negative loop.
Emerging research hints that wearable devices might amplify that loop. In a study on people with atrial fibrillation, heart rate trackers were linked to more frequent symptom-checking and higher anxiety.
A larger study, involving a random sample of around 500 smartwatch users, found a similar pattern. People reported feeling anxious when their physiological data looked abnormal. Some participants even reported feeling dependent on their health tracker, and become frustrated when they couldn’t wear their device or forgot to. Some recognised the effect and considered giving the device up altogether.
However, wearables don’t appear to have the same effect on everyone. For some, this information can be reassuring and may even reduce anxiety.
Critically, we don’t know why for some wearables provide reassurance, and for others they increase anxiety.
Avoiding health anxiety
There are many reasons people may wish to use wearables. Often, it’s because this health information can be useful – such as alerting us to issues we may otherwise miss. But monitoring the body in this way can also sometimes make us feel worse.
Taken together, the current evidence suggests this effect may be especially pronounced in people prone to anxiety, as well as in conditions where hyper-monitoring the body or behaviour can be maladaptive – such as eating disorders.
As with many things in life, it’s all about moderation. If you find yourself worrying about your data more than your wellbeing, try an experiment: leave the watch off for a day or hide the data so you’re not receiving constant feedback about your body.
Notice how your body feels without the tracking. You might discover what that hiker did: that sometimes trusting what you feel is better.
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