{"entity":{"id":"rejuv-measure-wearables-and-step-counts","kind":"technology","name":"Wearables and step counts: measuring what someone actually does","aka":[],"tldr":"A wrist or hip device records steps, activity and sleep continuously, at home, without anyone being asked a question. It measures behaviour rather than capacity, which is the gap a corridor test leaves, and it is the one measurement of recovery that does not stop when the person leaves the hospital.","summary":"Every other measurement here is a snapshot taken in a clinical setting. A wearable is a continuous record of what the body did, which is a different and complementary thing: a walk test measures what a person can do when encouraged, a step count measures what they did on a Tuesday.\n\nWhat it adds. Performance status, the single number most used to decide whether somebody is fit for treatment, is assigned by a clinician in a consultation and is known to disagree between observers and between clinician and patient. Continuous activity data is an objective alternative, and the PRO-TECT weekly survey included a performance status question for exactly this reason. Step counts also track recovery after surgery day by day rather than at a six-week appointment, and they capture sleep, which is otherwise measured only by questionnaire.\n\nWhat the evidence does and does not say. The association between higher activity and better outcomes in cancer populations is consistent and is reported in many cohorts. That association is not the same as showing that monitoring somebody's steps changes anything. The randomised evidence that a measurement can be an intervention, on this front, is for symptom reporting with a clinical response attached, not for activity tracking, and this record does not borrow that evidence. A wearable with no response attached is a record, not a treatment.\n\nThe practical limits are specific and worth naming.\n\nValidity differs by device and by speed. Consumer step counters are least accurate in exactly the population of interest, people walking slowly with an aid, and a device validated in healthy walkers can misread them substantially.\n\nWear time is the dropout problem again in another form. People stop wearing devices, and they stop when unwell, so a dataset of worn days has the same informative-missingness structure as a dataset of returned questionnaires.\n\nAccess is unequal. A device, a phone and a data plan are not free, so a measurement that depends on them will systematically miss the people with the fewest resources, who are also the people least likely to be offered rehabilitation.\n\nThere is no agreed outcome. Steps per day, moderate-to-vigorous minutes, sedentary time, sleep efficiency and cadence are all reported, with no consensus on which is the endpoint or what change counts as meaningful, which is the state the quality of life field was in before the minimally important difference work was done.\n\nThe honest position is that this is the most promising measurement on this front and the least mature. It is included here, rather than left out, because readers are already wearing these devices and deserve to know what the data can and cannot support.","status":"emerging","asOf":"2026-10-02","wikipedia":"https://en.wikipedia.org/wiki/Activity_tracker","links":[{"label":"Basch et al., Effect of electronic symptom monitoring on patient-reported outcomes among patients with metastatic cancer: the PRO-TECT randomized clinical trial (JAMA 2022)","url":"https://doi.org/10.1001/jama.2022.9265"},{"label":"Basch et al., Comparing the effectiveness of electronic symptom monitoring versus usual care in improving survival among patients with metastatic cancer: the PRO-TECT trial, final research report (Europe PMC, PMID 41915775)","url":"https://europepmc.org/article/MED/41915775"},{"label":"Jones et al., Cardiorespiratory exercise testing in clinical oncology research: systematic review and practice recommendations (Lancet Oncol 2008)","url":"https://doi.org/10.1016/S1470-2045(08)70195-5"}],"tags":["rejuvenation","survivorship","measurement","objective"],"related":["rejuv-measure-missing-data-and-who-is-not-asked","rejuv-mind-sleep-after-cancer"],"cancers":["colorectal","nsclc","breast-hr-positive","multiple-myeloma"],"sections":["rejuvenation","supportive-care","ai-computation"],"technologies":["rejuv-measure-functional-tests","rejuv-measure-epro-as-treatment","telehealth-oncology","exercise-prescription-after-cancer","structured-exercise-survivorship","geriatric-assessment"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["quality-of-life","real-world-evidence"],"trials":[],"people":[],"bottlenecks":["b-patient-voice","b-biomarker-validation","b-survivorship"],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"principle":"Accelerometry samples limb or trunk acceleration continuously and derives step counts, activity intensity bands and sleep estimates from the signal. Because the record is passive and continuous, it measures habitual behaviour in the person's own environment rather than capacity under standardised conditions, which is a different construct and not a substitute.","strengths":["Measures behaviour at home, which the corridor tests cannot","Continuous rather than a snapshot, so recovery can be tracked day by day","An objective alternative to clinician-assigned performance status","Captures sleep, otherwise measured only by self-report"],"limitations":["No randomised evidence that tracking activity changes outcomes, unlike symptom reporting with a clinical response","Consumer devices are least accurate in slow and aided walkers","People stop wearing devices when unwell, which is informative missingness again","Requires a device, a phone and a data plan, so it misses those with the fewest resources","No agreed endpoint and no agreed meaningful change"]},"route":"/technologies/rejuv-measure-wearables-and-step-counts/","neighbours":{"technology":[{"id":"rejuv-measure-epro-as-treatment","kind":"technology","name":"Asking people how they are, every week, as a treatment in its own right","route":"/technologies/rejuv-measure-epro-as-treatment/"},{"id":"geriatric-assessment","kind":"technology","name":"Geriatric assessment","route":"/technologies/geriatric-assessment/"},{"id":"rejuv-mind-sleep-after-cancer","kind":"technology","name":"Sleep after cancer: how common insomnia is, how long it lasts, and the treatment that works","route":"/technologies/rejuv-mind-sleep-after-cancer/"},{"id":"structured-exercise-survivorship","kind":"technology","name":"Structured exercise programmes after curative treatment","route":"/technologies/structured-exercise-survivorship/"},{"id":"telehealth-oncology","kind":"technology","name":"Telehealth and hospital-at-home in oncology","route":"/technologies/telehealth-oncology/"},{"id":"exercise-prescription-after-cancer","kind":"technology","name":"The exercise prescription after cancer: the dose the guidelines state","route":"/technologies/exercise-prescription-after-cancer/"},{"id":"rejuv-measure-missing-data-and-who-is-not-asked","kind":"technology","name":"The questionnaires that were never returned, and the people never asked","route":"/technologies/rejuv-measure-missing-data-and-who-is-not-asked/"},{"id":"rejuv-measure-functional-tests","kind":"technology","name":"Walking, gripping and standing up: the tests that take five minutes","route":"/technologies/rejuv-measure-functional-tests/"}],"cancer":[{"id":"colorectal","kind":"cancer","name":"Colorectal cancer","route":"/cancers/colorectal/"},{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"multiple-myeloma","kind":"cancer","name":"Multiple myeloma","route":"/cancers/multiple-myeloma/"},{"id":"nsclc","kind":"cancer","name":"Non-small-cell lung cancer","route":"/cancers/nsclc/"}],"section":[{"id":"ai-computation","kind":"section","name":"AI & Computation","route":"/fronts/ai-computation/"},{"id":"rejuvenation","kind":"section","name":"Recovery & Rejuvenation","route":"/fronts/rejuvenation/"},{"id":"supportive-care","kind":"section","name":"Supportive Care & Survivorship","route":"/fronts/supportive-care/"}],"term":[{"id":"quality-of-life","kind":"term","name":"Quality of life","route":"/terms/quality-of-life/"},{"id":"real-world-evidence","kind":"term","name":"Real-world evidence","route":"/terms/real-world-evidence/"}],"bottleneck":[{"id":"b-biomarker-validation","kind":"bottleneck","name":"Biomarkers are not validated or standardised","route":"/bottlenecks/b-biomarker-validation/"},{"id":"b-patient-voice","kind":"bottleneck","name":"Patients lack understanding, navigation and agency","route":"/bottlenecks/b-patient-voice/"},{"id":"b-survivorship","kind":"bottleneck","name":"Survivorship and late effects are neglected","route":"/bottlenecks/b-survivorship/"}]}}