Statistical machine learning of sleep and physical activity phenotypes from sensor data in 96,220 UK Biobank participants
Activity counts measure attention, not model quality. Missing counts are unknown. Publication status follows the linked source; a listed venue alone does not confirm peer review.
Willetts and colleagues developed a machine-learning model combining balanced random forests with hidden Markov models to detect activity and sleep modes from simple wrist-worn activity monitors. The model classified free-living behaviours with 87% accuracy across 159,504 recorded minutes from 132 adults. Applied to 96,220 UK Biobank participants, it showed, for example, that men spend more time in low- and high-intensity behaviours while women spend more time in mixed behaviours.
- Result: The authors show that physical activity and sleep behaviours can be classified with 87% accuracy in 159,504 minutes of recorded free-living behaviours from 132 adults.
- Venue
- Scientific Reports
- Published
- 2018
- arXiv
- Not reported
- PMID
- Not reported
- Signals
- Not reported
- Form factor
- Not reported
- Devices
- Subjects
- 132 adults
- Code
- Not reported
- Added
- Oct 15, 2026
Abstract
Current public health guidelines on physical activity and sleep duration are limited by a reliance on subjective self-reported evidence. Using data from simple wrist-worn activity monitors, we developed a tailored machine learning model, using balanced random forests with Hidden Markov Models, to reliably detect a number of activity modes. We show that physical activity and sleep behaviours can be classified with 87% accuracy in 159,504 minutes of recorded free-living behaviours from 132 adults. These trained models can be used to infer fine resolution activity patterns at the population scale in 96,220 participants. For example, we find that men spend more time in both low- and high- intensity behaviours, while women spend more time in mixed behaviours. Walking time is highest in spring and sleep time lowest during the summer. This work opens the possibility of future public health guidelines informed by the health consequences associated with specific, objectively measured, physical activity and sleep behaviours.
Verbatim fromthe publisher's DOI record· Publisher licence: https://creativecommons.org/licenses/by/4.0

Key results
How it works
- Cohort
- 132 adults
Devices· 1
Illustrations by form factor; product photos are added as licences clear.
Datasets used· 1
Cite
@article{willettsukbsleepactivity2018,
title = {{Statistical machine learning of sleep and physical activity phenotypes from sensor data in 96,220 UK Biobank participants}},
author = {Matthew Willetts and Sven Hollowell and Louis Aslett and Chris Holmes and Aiden Doherty},
year = {2018},
journal = {Scientific Reports},
doi = {10.1038/s41598-018-26174-1}
}History
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