"It's like a toxic relationship": researchers ask what activity trackers do to their users

Wearable activity trackers have been treated in the research literature mainly as instruments — tools that measure behaviour and, sometimes, change it. A study published in PLOS Digital Health on 20 February treats them instead as relationships, and asks what kind [s1].

The design is qualitative and exploratory: inductive thematic analysis of semi-structured interview transcripts from 11 regular wearable activity tracker users, eight of them female, aged between 18 and 59 with a mean age of 30.73 [s1]. The authors state that this is, to their knowledge, the first study to directly examine the conflict faced by wearable activity tracker users [s1].

Eleven people is a very small sample, and the authors present it as exploratory rather than representative. What it produces is not a prevalence estimate but a vocabulary.

Four questions users kept returning to

Four themes and nine sub-themes captured participants' internal conflict, and the themes are phrased as questions: Who knows best? Who's in charge? Who am I without it? And what is happening to me? [s1]

Between them, the themes describe conflict around navigating a mismatch between the device's data and the user's own perception, how a tracker changed their behaviour, how much control the tracker had over them, whether their device use was positive at all, and how they would act and feel if they stopped using it [s1].

The authors report that participants experienced substantial internal conflict from wearable activity tracker use, and that the intensity of the device–user relationship was clear, suggesting device dependency and perceived device importance [s1].

Two further observations are the ones with theoretical weight. The findings suggested blurred boundaries between intrinsic and extrinsic motivation, likely due to device embodiment — the tracker being experienced as part of the self rather than as an external instrument — and highlighted the role of pressure in driving increased physical activity [s1]. And the authors raise, as an implication, the potential long-term negative impact of these devices on bodily intuition [s1].

That last point is the one with clinical relevance. If a device systematically substitutes for interoception — the capacity to read fatigue, hunger, exertion and recovery from internal signals — then the behaviour change it produces comes with a cost that step-count trials are not designed to detect.

The study's stated implications are aimed squarely at that gap: the integration of activity trackers in healthcare services, and recommendations around healthy use [s1]. The authors also note that theoretical underpinnings remain unclear around wearable activity tracker use [s1].

The devices do move behaviour

The counterweight is that trackers, especially when combined with game mechanics, demonstrably change the number they measure. A 12-week parallel randomised controlled trial published in the American Journal of Preventive Medicine on 6 February tested different gamification delivery strategies in young adults [s2].

Conducted from April 2024 to January 2025 and registered on ClinicalTrials.gov (NCT06818071), the trial randomised healthy university students aged 18 to 35 to one of four conditions: sequential delivery of gamified elements, cumulative delivery, explicit gamification through a commercial mobile game, or a tracking-only control [s2]. Gamified elements included points, leaderboards and social interaction, and the primary outcome was daily step count measured in a free-living context [s2].

Among 246 participants, all intervention groups significantly increased daily step count, with cumulative delivery producing the largest gain at +2,326 steps (SD = 303), sustained at follow-up [s2]. Explicit gamification through a commercial mobile game showed delayed but longer-lasting effects [s2]. The authors conclude that delivering gamified elements cumulatively rather than overwhelming users produced increases exceeding thresholds previously associated with lower mortality risk, and argue such strategies should be integrated into public health efforts [s2].

Note the measurement: the primary outcome was app-based self-report of daily step count in a free-living context [s2]. And note the population: university students, over 12 weeks, with a 4-week follow-up. Neither the durability beyond four months nor the effect in older or less healthy populations is established by this trial.

Set against the qualitative work, the two findings are not in conflict. Pressure raises step counts. That is what the RCT measures and what the interview study describes from the inside.

And the data has nowhere settled to go

A third question sits behind both: what happens to the data. An opinion paper published in EJIFCC on 2 February notes that with over 20 smartwatch manufacturers offering multiple models with diverse health-monitoring capabilities, basic questions remain open — what data is collected, how it is stored, and whether any of it should be integrated into medical records [s3].

Beyond risks of data misuse for financial purposes, the paper identifies persistent challenges in ensuring accuracy, reliability and standardisation, and points to an IFCC best practice publication on incorporating patient-generated health data into electronic health records as setting out questions that must be addressed before smartwatch data can contribute meaningfully to healthcare [s3]. This is an opinion piece, not a study, and should be read as an argument rather than evidence.

What this does and does not mean for a reader

It does not mean activity trackers are harmful. Eleven interviews cannot establish that, and the authors do not claim it [s1]. What the study offers is a description of experiences that quantitative trials do not capture, generated from users who chose to wear these devices regularly.

The practical implication the authors themselves draw is about healthcare integration — that services adopting these devices should think about recommendations for healthy use, not only about uptake [s1]. That is a governance question, and at present it is being answered mainly by manufacturers.

What to watch

Whether larger, more diverse qualitative and mixed-methods work replicates the dependency and bodily-intuition themes, which currently rest on a single small sample [s1]. And whether trials of tracker-based interventions begin measuring anything besides the metric the tracker produces [s2].

Sources

1. [s1] "It's like a toxic relationship": Examining internal conflict experienced in wearable activity tracker users. PLOS Digital Health, 20 February 2026. https://doi.org/10.1371/journal.pdig.0001136
2. [s2] Effects of Different Gamification Delivery Strategies on Physical Activity in Young Adults: An RCT. American Journal of Preventive Medicine, published online 6 February 2026. https://doi.org/10.1016/j.amepre.2026.108297
3. [s3] Opinion Paper: Smartwatches in Healthcare: Revolutionizing Health or Creating Data Confusion? EJIFCC, 2 February 2026. https://pmc.ncbi.nlm.nih.gov/articles/PMC12882078/