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Research Shows Fitness Watch Can Accurately Track Sleep Patterns

Results from first study comparing consumer sleep tracker against research-grade tracker over two weeks in home environment published in Journal of Sleep 

Menlo Park, CA, and Australia, December 9, 2019 – With the growing popularity of fitness watches that track personal data – including sleep - more people are using information from them to understand and make choices about their health.

But is the information these trackers provide accurate? And can it be helpful to doctors?

A study conducted by researchers at SRI International’s Center for Health Sciences (Menlo Park, CA) and Monash University (Australia) found that the sleep monitoring capacity of one model of Fitbit watch may be just as effective in almost every way as a research-grade actigraph – the accepted standard for measuring sleep outside of laboratory settings.

“This research demonstrates the potential clinical utility of a consumer sleep-tracking device, but many people – not just those with insomnia – are interested in tracking their sleep patterns as a means to improve their sleep and health,” said Massimiliano de Zambotti, Ph.D., sleep neuroscientist, and a lead in sleep technology development and testing at SRI International’s Human Sleep Research Program.

“This is the first research comparing a commercially-available sleep tracker such as the Fitbit against a research-grade tracker over two weeks in participants’ home environments, and it shows that the commercial tracker can indeed provide reliable, useful information,” Dr. Zambotti added.

The researchers collected sleep data from 25 people - previously confirmed through an in-laboratory sleep assessment to have chronic insomnia - using the Fitbit Alta HR and the validated, research-grade Actiwatch Spectrum Pro. The data were collected in the patients’ homes for one week before they received insomnia treatment and again for a week after treatment. 

Researchers compared how well the Fitbit and Actiwatch tracked key sleep outcomes - including sleep time, sleep latency, sleep efficiency and wake after sleep onset.

“Overall, the Fitbit Alta HR performed equally well to the research-grade actigraph in almost every way,” said Professor Sean P.A. Drummond, from the Turner Institute for Brain and Mental Health. “Fitbit Alta HR can measure sleep in someone with insomnia just as well as the research-grade device commonly used.”

Earlier this year we published extensive guidelines for evaluating the performance and use of commercial sleep-trackers in measuring sleep. It’s worth understanding how to use this technology correctly, because it could provide an opportunity to advance sleep and circadian science,” said Dr. de Zambotti. 

The researchers caution there were some limitations to their research and findings. As insomnia symptoms got worse among study participants, the Fitbit became less accurate - the Fitbit thought the person was asleep, when in fact they were just lying still. And neither device was useful in making an initial diagnosis of insomnia or in tracking treatment outcomes.

The study, published in the Journal of Sleep Research, concluded: “Both researchers and health professionals may consider the use of this (Fitbit) device as an alternative to the more expensive research-grade actigraphs. Further work is needed in research settings, clinical settings and consumer settings to ensure appropriate data interpretation.”