I watched my colleague manically walking round the hotel, staring at his watch until he had closed the ring on his apple watch thus achieving his activity target for the day. I bet you've seen something similar? 6 months later, we were sat in a bar and the motivation to close rings on his apple watch had long since passed, genial conversation and a cold beer proving a more powerful attraction than pacing corridors late at night. Wearables - do they really make a difference?
A great many of us are wearing smartwatches, rings or straps that count steps, record heart rate, measure sleep and tell us our current ‘state’. The implicit promise is seductive: see the number, change the behaviour, improve the life.
The promise deserves scrutiny. Marketing claims and testimonials are abundant; scientific evidence is more circumspect. But does more biometric feedback actually produce meaningful, sustained changes in what people do? The answer is "sometimes, modestly, and under specific conditions" and understanding those conditions matters far more than the device you are using.
The evidence? Physical activity
The best-studied use is for recording physical activity, and here the news is cautiously positive. An umbrella review of 39 systematic reviews found that wearable activity trackers increase physical activity by roughly 1,800 steps per day, about 40 minutes of walking with small accompanying improvements in weight and body composition (Ferguson et al., 2022).
That is a real effect, and at population scale a valuable one. But note, it’s a modest increase in one easily counted behaviour (steps), measured over periods that rarely exceeded a year. It is not evidence of transformed lifestyles.
In another trial in Singapore (TRIPPA trial), 800 employees were given a Fitbit, with or without financial incentives. Only the incentive groups increased activity meaningfully at six months, and once payments stopped the gains eroded. The tracker alone produced no improvement in health outcomes such as weight or blood pressure (Finkelstein et al., 2016). The message is clear, unless you are motivated, wearing a tracking device such as a fitbit won’t make any meaningful difference.
The evidence: Weight loss
In the IDEA trial, 471 adults on a weight-loss programme were randomised to add either a wearable device or standard self-monitoring. After two years, the wearable group had lost less weight, 3.5 kg against 5.9 kg (Jakicic et al., 2016). The device did not help, and may have justified thinking along the lines of "the watch says I've earned it" or displaced the reflective thinking that self-monitoring weight loss requires.
And we stop wearing them
And there is the question of whether people keep wearing them. In an observational study of 711 tracker users followed for over 300 days, sustained use was the exception. What typically gained was people gradually stopped paying attention to the data (Hermsen et al., 2017). Feedback that is no longer looked at cannot change anything.
What’s going wrong?
Why would information about ourselves fail to move us to action, or even degrade our efforts? There are two possible thoughts.
First, measurement changes motivation. In a series of experiments, Etkin (2016) found that quantifying an activity, counting steps while walking, pages while reading, increased how much people did in the moment but reduced how much they enjoyed it, and reduced their willingness to continue once tracking stopped. The number crowds out the intrinsic reward. I have first hand experience of this. Walking on a crisp beautiful fresh day in the Brecon Beacons I found myself looking repeatedly at my pace rather than the stunning views in front of me. The walk was far less enjoyable than had I simply turned the data collection off and just enjoyed the sheer pleasure of being out there.
Second, feedback shapes experience, not just behaviour. Sleep researchers have documented "orthosomnia" patients presenting with insomnia complaints driven by tracker scores rather than by any clinically verifiable sleep problem (Baron et al., 2017). In an elegant experiment, people with insomnia were shown sham feedback from a sleep monitor: those told they had slept poorly reported worse mood, sleepiness and attention the next day, regardless of how they had actually slept (Gavriloff et al., 2018). The score became the symptom. Given sleep trackers are not that accurate this is rather worrying.
And the data illusion is getting worse!
The market has moved beyond steps to "recovery", "strain", "stress" and brain states. The refereed literature has not kept pace. A systematic review of wearables for detecting stress and mental health conditions found little evidence that feeding stress scores back to users improves outcomes (Hickey et al., 2021). The trouble is, independent trials of recovery-strap products are scarce, and much of what exists is manufacturer-funded. To be clear, I have nothing against manufacturers doing research as long as it is good science and fully open to critical scrutiny.
Consumer EEG headbands (devices that scan your brain waves) have been tested more rigorously, and the results are not compelling when it comes to behaviour change either. The evidence is weak. In one trial, participants using a headband alongside an app improved their mindfulness no more that those using the app alone (Acabchuk et al., 2021). The meditation worked. The neurofeedback did not add to it.
Some of these tools are very good
Don’t make the mistake of thinking I am saying these tools do not accurately record what they purport to measure. Some consumer grade heart rate chest straps for example have been the go-to tool in many a research project such is their accuracy. But is not a black or white picture. It’s a continuum from hopelessly inaccurate and unreliable to scientific grade data depending on what is being measured and the choice of tool used.
Is there a place for wearables?
Wearables are facilitators of behaviour change, not drivers of it (Patel et al., 2015). The device supplies information; the change requires motivation, a plan, and an environment that supports it. No amount of devices will make you happier, fitter, thinner, more rested, without you wanting to make the changes and doing the work required.
Personally, I would not be without my smartwatch. I use it everyday to track my fitness and to record my cycling and hiking and I love seeing the impact of sessions I have done on my fitness. But! Not because I am fitter per se but because of what that fitness allows me to do and the fun it means I can have with friends in the outdoors.
In summary
The pattern is consistent. Biometric feedback produces small gains where the behaviour is simple, countable and already valued; it produces nothing where the metric is opaque or the underlying behaviour is not being addressed; and it can produce harm where the number becomes an object of anxiety or a substitute for enjoyment.
My top tips
1. Devices can be useful dashboards
Behaviour change frameworks are clear that sustained change requires capability, opportunity and motivation together (Michie et al., 2011). A tracker addresses only the information component of capability. Pair it with the elements the evidence says do the work: a specific goal, a plan for when and where, and a person (coach, colleague or partner) who knows the goal. In the trials that succeeded, the device was part of a structured programme, not the programme itself.
2. Put the budget into commitment, not gadgets.
If your budget is limited, and you have to choose between the tech and commitment mechanisms, such as pledges, an accountability partner (such as a coach) then the evidence favours the mechanisms.
3. Protect intrinsic motivation.
Etkin's findings suggest limiting how often people look at their numbers, and periodically tracking nothing at all. Encourage people to choose activities they enjoy and to notice how they feel, not only what they scored. Sometimes, just turn off your bike computer and ride for the sheer pleasure of doing so. Or, forget your pace or how many steps you have taken and instead enjoy the view whilst you are out walking.
4. Teach interpretation, not just measurement.
Consumer devices estimate sleep stages and stress with meaningful error, and the harm from orthosomnia comes from taking scores as ground truth. Trends over weeks are informative, single nights are noise, and how you feel is a legitimate data point, far more so than what the device says. Where a score consistently contradicts experience, the score is the thing to doubt first.
5. Plan for abandonment as the default.
Most people stop wearing devices within months. Rather than fighting attrition, design for it: use a tracker intensively for a defined period to establish a baseline and build a habit, then deliberately step down. The goal is a behaviour that survives the battery dying. It’s amazing how, over time and enough introspection, you know what the numbers are without looking at the screen.
Remember, The Data Is Not the Behaviour.
At Epiphanies LLP, we are deeply committed to optimising the performance of the individual, teams and organisations. And we use wearable technology to help people understand how the mechanisms in their body affect their behaviour for better or worse. We help people use these insights to achieve their ambitions and goals. It’s the routines and habits that we help create that drive performance. To this end, wearables can be great triggers of curiosity and engagement.
References
Acabchuk, R. L., Simon, M. A., Low, S., Brisson, J. M., & Johnson, B. T. (2021). Measuring meditation progress with a consumer-grade EEG device: Caution from a randomized controlled trial. Mindfulness, 12(1), 68–81. https://doi.org/10.1007/s12671-020-01497-1
Baron, K. G., Abbott, S., Jao, N., Manalo, N., & Mullen, R. (2017). Orthosomnia: Are some patients taking the quantified self too far? Journal of Clinical Sleep Medicine, 13(2), 351–354. https://doi.org/10.5664/jcsm.6472
Etkin, J. (2016). The hidden cost of personal quantification. Journal of Consumer Research, 42(6), 967–984. https://doi.org/10.1093/jcr/ucv095
Ferguson, T., Olds, T., Curtis, R., Blake, H., Crozier, A. J., Dankiw, K., Dumuid, D., Kasai, D., O'Connor, E., Virgara, R., & Maher, C. (2022). Effectiveness of wearable activity trackers to increase physical activity and improve health: A systematic review of systematic reviews and meta-analyses. The Lancet Digital Health, 4(8), e615–e626. https://doi.org/10.1016/S2589-7500(22)00111-X
Finkelstein, E. A., Haaland, B. A., Bilger, M., Sahasranaman, A., Sloan, R. A., Nang, E. E. K., & Evenson, K. R. (2016). Effectiveness of activity trackers with and without incentives to increase physical activity (TRIPPA): A randomised controlled trial. The Lancet Diabetes & Endocrinology, 4(12), 983–995. https://doi.org/10.1016/S2213-8587(16)30284-4
Gavriloff, D., Sheaves, B., Juss, A., Espie, C. A., Miller, C. B., & Kyle, S. D. (2018). Sham sleep feedback delivered via actigraphy biases daytime symptom reports in people with insomnia: Implications for insomnia disorder and wearable devices. Journal of Sleep Research, 27(6), e12726. https://doi.org/10.1111/jsr.12726
Hermsen, S., Moons, J., Kerkhof, P., Wiekens, C., & De Groot, M. (2017). Determinants for sustained use of an activity tracker: Observational study. JMIR mHealth and uHealth, 5(10), e164. https://doi.org/10.2196/mhealth.7311
Hickey, B. A., Chalmers, T., Newton, P., Lin, C.-T., Sibbritt, D., McLachlan, C. S., Clifton-Bligh, R., Morley, J., & Lal, S. (2021). Smart devices and wearable technologies to detect and monitor mental health conditions and stress: A systematic review. Sensors, 21(10), 3461. https://doi.org/10.3390/s21103461
Jakicic, J. M., Davis, K. K., Rogers, R. J., King, W. C., Marcus, M. D., Helsel, D., Rickman, A. D., Wahed, A. S., & Belle, S. H. (2016). Effect of wearable technology combined with a lifestyle intervention on long-term weight loss: The IDEA randomized clinical trial. JAMA, 316(11), 1161–1171. https://doi.org/10.1001/jama.2016.12858
Michie, S., van Stralen, M. M., & West, R. (2011). The behaviour change wheel: A new method for characterising and designing behaviour change interventions. Implementation Science, 6, 42. https://doi.org/10.1186/1748-5908-6-42
Patel, M. S., Asch, D. A., & Volpp, K. G. (2015). Wearable devices as facilitators, not drivers, of health behavior change. JAMA, 313(5), 459–460. https://doi.org/10.1001/jama.2014.14781
Patel, M. S., Asch, D. A., Rosin, R., Small, D. S., Bellamy, S. L., Heuer, J., Sproat, S., Hyson, C., Haff, N., Lee, S. M., Wesby, L., Hoffer, K., Shuttleworth, D., Taylor, D. H., Hilbert, V., Zhu, J., Yang, L., Wang, X., & Volpp, K. G. (2016). Framing financial incentives to increase physical activity among overweight and obese adults: A randomized, controlled trial. Annals of Internal Medicine, 164(6), 385–394. https://doi.org/10.7326/M15- 1635