Fitbit's fitness trackers and more recently its smartwatches have sold in their millions, with the simple aim of hoping its wearables can help people get fitter and healthier.
But now it's going beyond burning calories and increasing your VO2 Max. With the introduction of the SpO2 sensor that lives inside its Ionic, Versa and Charge 3 devices, it also wants to start exploring the possibility of detecting and monitoring serious health conditions.
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That journey into serious health tracking, though, began before those new wearables were on the scene. Over the last few years, other Fitbit devices have been at the heart of hundreds of clinical studies and trials, changing the way that medical research can now be conducted. It's improving the recruitment process for these studies and retention so that data can be collected over long periods of time.
We've taken a closer at some of those studies and trials that are embracing Fitbit's wearable tech in the hope of making major breakthroughs in the health space.
Teaming up with Fitabase
While Fitbit does have a Health Solutions division that points researchers in the right direction, it's had some assistance from the folks over at Fitabase. The analytics company has been key to much of the medical work done with Fitbit trackers.
This is a platform that makes it easy for researchers to harvest data from all the available Fitbit wearables, with much more fine-grain detail than you’ll see in the Fitbit app.
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Fitabase founder Aaron Coleman initially developed the concept in San Diego’s UCSD Center for Wireless Population Health Systems, before spinning it into its own platform in “late 2011”. “We’ve been part of almost 500 research studies to date,” says Coleman. “A significant portion, likely more than half of all academic research using Fitbit, used Fitabase”.
Fitbit itself offers a platform for companies looking to get wearables onto the wrists of their workforce. But it’s Fitabase that acts as a “turnkey” solution for researchers, so they don’t have to put too much time or budget into making a consumer gadget work outside its comfort zone.
“We’ve partnered with [Fitbit] to best support researchers. We jointly engage with a research group on the hardware and software side of things to help them be successful,” says Coleman.
The strength of Fitbit devices is what makes some dismiss these gadgets as useless for serious research: that they are made as consumer devices. People just don’t enjoy using or wearing medical-grade sensors as much as Fitbits.
“We lack tools generally for realistic long term wear,” says Coleman. “We’ve seen some amazingly high compliance, in the 90% range, in studies that asked participants to wear a Fitbit. Good battery life contributes to that as well”. He says such high adherence is “almost unheard of”.
The Fitabase platform also mitigates the issue of the somewhat relaxed approach to data-gathering you’ll see in the Fitbit app on your phone. However, the trackers can “produce high-resolution datasets. One-min values for activity, energy expenditure, sleep and heart rate. That gives a really great picture of the 24 hour activity cycle,” says Coleman.
But what research has actually been done using Fitbits? A huge array of subjects and conditions have been, and are, under the spotlight.
Fitbits versus multiple sclerosis
A fairly specific trial was attempted by researchers from the University of California, published in 2016. It looked at the “ambulatory function” of sufferers of multiple sclerosis.
This condition affects the myelin sheath that coats nerves, disrupting the signals sent through the central nervous system. Its effects are wide-ranging, but include difficulty walking and muscle spasms.
“Current metrics fail to capture potentially important variability in walking behaviour,” the research abstract reads. A Fitbit Flex was used to measure the activity of participants for four weeks, including an initial seven days where the Flex’s readings were compared with those of an ActiGraph, a medical-grade (and much chunkier) tracker.
One aim of the research was to find whether a consumer fitness tracker is good enough to monitor relapsing remitting MS, where “attacks” of symptoms happen between periods of relative stability, or no symptoms at all.
The results were not unsurprising, but quite interesting. Researchers found, as we have, that Fitbit's do tend to overestimate step counts. However, the participants tended to use the Fitbit Flex much more consistently than the ActiGraph “pro” tracker: “96% compared to 91% wear-time”.
After the four week trial, all but three of the 99 testers were still on board. Two left citing “personal preference” and one couldn’t get it to work with their PC or phone. The rest stayed involved.
Fitbits are, obviously, not suitable for monitoring all conditions. But this trial does seem to show that they are well-suited to long-term monitoring of ones like this. After all, the Fitbit Flex is at least consistent in its inconsistency. “These data demonstrate the feasibility, practicality and validity of longer-term continuous monitoring using commercial consumer-friendly accelerometers,” the researchers wrote.
An eye on hip replacements
Another piece of research by the Mayo Clinic in Minnesota monitored the recovery of patients following a total hip arthroplasty. That’s a hip replacement.
“Recommended activities include gradually increased walking and light household activities. Movement is essential to a healthy recovery,” says the Rothman Insitute’s Fabio R. Orozco, a hip and knee surgeon.
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In the trial, published in the Bone&Joint Journal, 33 patients over the age of 60 were monitored using an ankle-worn Fitbit. The aim was to see if a consumer tracker would work for at-home tracking. When a physiotherapy patient leaves hospital, their physiotherapy recovery often drops off as they lose the motivation to stick to a recovery plan.
“Little is known objectively about the recovery of mobility in the early post-operative period,” the researchers wrote. The research would have been stronger from our perspective if there were a control groups without Fitbits. There wasn’t one.
However, the study still found 89% adherence over the test’s 30 days. And that seems impressive given that the Fitbit would have had to be recharged a few times during the tests, and some of the participants were over 80: not the first fitness tracker demographic you might consider.
The Fitbits’ readings showed a tenfold mean increase of steps between the first day after the operation and the 30th. "Such monitoring may allow for the early identification and targeted intervention in patients who recover slowly,” the researchers found. There’s a use for Fitbits other than just as a way to motivate us to move more.
Fit mother, fit baby?
In some trials the Fitbit trackers’ identity is much more incidental. It only matters what they can do, not that they are a consumer device.
One of the more interesting and controversial studies published online looks at the relationship between the exercise levels of pregnant women and gene expression in their offspring.
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Its aim was to shed some light on the anecdotal theory that "offspring born to mothers who exercise during pregnancy have been shown to have reduced birth weight and body weight during adolescence.”
A Fitbit Flex was used to monitor the step counts of mothers in the last six months of pregnancy. They were then split into groups: those who took more than 6000 steps a day, and those who didn’t.
The squeamish might want to miss the following paragraph.
Researchers then analysed the excised foreskin of male babies. The trial took place in the US, where approximately 71.2% of males are circumcised according to a 2016 study.
Sure enough, they found some results. “Low levels of physical activity during pregnancy are associated with increased gene expression of markers of adipogenesis and decreased markers involved in insulin sensitivity and glucose uptake,” they wrote.
At this point we’ll walk away from this study as we can’t find any citations beyond an excerpt published in the journal Medicine & Science in Sports & Exercise. And we certainly aren’t qualified to comment on the results. However, it does demonstrate the breadth of Fitbit-powered studies.
Perhaps the largest Fitbit-related trial of all is currently ongoing. In November 2017, Fitbit announced thousands of its trackers would be used in the US National Institute of Health’s All of Us programme.
This is a planned million-participant-strong medical experiment, although the announcement says only 10,000 Fitbits will be used initially.
This means that 10,000 people across the US are using Fitbits. Their activity, sleep and heart rate data will be gathered to see how it corresponds to their location, age and any conditions they may have.
This is one of those trendy “big data” trials. It will eventually be a repository that other researchers can use to spot trends across the population. Well, the US population. Any US-based adult can sign up for the All of Us experiment, although there’s no button in the form to claim a “free” Fitbit.
We write about consumer wearables. We also occasionally write about medical-grade wearables and the technology in development to make future clinical devices. Consumer wearables can some times be dismissed as tech fluff, but it’s reassuring to know researchers across the world have and continue to find meaningful uses for them.