Can a fun fitness app help those who Can't smell? UK trial aims to find out

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion criteria * Age ≥ 40 years * Objective hyposmia, defined as scoring below the 15th percentile (adjusted for age/sex) on UPSIT * Ability and willingness to provide written informed consent * Proficiency in written and spoken English sufficient to complete study procedures. * Willingness and ability to attend baseline (in-person), 9-month (remote), and 18-month (in-person) assessments. * Access to telephone or internet for interim communication. Specifically, in possession of a suitable smartphone (screen size minimum 4.6 inch; Android version 9 or iOS version 15 or newer). * Physical activity threshold: During the 4-week eligibility run-in, the mean daily step count must be \<7,000 steps/day, calculated over ≥21 valid days (a valid day = ≥10 hours wear time or ≥1,000 steps). If recruitment after the first 2 months is \<60-70% of target, and subject to TSC/Sponsor approval and REC amendment, eligibility may be broadened to \<10,000 steps/day (i.e. participants averaging 7,000-9,999 steps/day become eligible). Exclusion criteria * Clinical diagnosis of PD, dementia, or other neurodegenerative conditions * Severe or unstable medical or psychiatric illness likely to impair participation * Use of agents known to alter olfaction (e.g. intranasal zinc, chronic corticosteroids) * Current enrolment in an interventional study within the past 3 months (standard research retention guidance). * Inability to complete study procedures in English, per investigator assessment * Unable to give consent * Participants not living independently in the community. Participants in nursing homes, hospitalised persons on in a non-institutionalised setting are excluded. * Subject's personal smartphone is Fitbit-incompatible i.e. Huawei P8 Lite; Huawei P9 Lite; Xiaomi Mi 6; Huawei P20 Lite * Activity level above threshold during eligibility run-in: mean daily step count ≥7,000 steps/day (or ≥10,000 steps/day if the broadened threshold is activated).