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Are FitBits a boon for your health – or a threat to your privacy?

Illustration/Anthony Ellison/Listener

One in five New Zealanders owns a fitness tracker, but what effect do they have? Donna Chisholm investigates.

The day I began to suspect my Fitbit was cheating on me, I realised our 18-month love affair was probably over. We’d been inseparable. It knew my heart better than I did. It was with me every step of the way. When it was pleased with me, my mood soared. Then I discovered that maybe I couldn’t trust it any longer. Like many lovers, it was undone by a digital double life – in this case, an app update. Suddenly, the heart rate it had measured so faithfully began averaging 10 beats a minute faster than it had for almost all the preceding year. Either it had been lying to me before or it was lying now. The trust was gone, the sense of betrayal real.

Now that insurer AIA is offering rewards to its 500,000 customers who upload health and exercise data from wearable devices such as Fitbits and Apple watches, it’s time to ask the big questions. How accurate – and secure – is that data? How useful is the technology for improving our health? And are there downsides we haven’t considered?

RelatedArticlesModule - Fitbits boon health or privacy threat

AIA was keen to promote the programme when it announced it in April, but wouldn’t answer questions we put to it in May. In publicity at the time, AIA said it wouldn’t get direct access to customers’ health or lifestyle information, but would be advised only of their status as bronze, silver, gold or platinum members – the tiers based on activity levels. Members would get premium discounts based on that status.

AIA’s Vitality scheme is owned by a separate company, South African insurer Discovery, but as numerous data breaches around the world have shown us, almost any information is hackable, either from within or without.

In 2011, the then three-year-old Fitbit company had to hide users’ data after discovering the trackers were revealing their sexual-activity statistics online. The company had made user profiles and activity public by default, but a month after the furore, it stopped users being able to list sex, with its varying degrees of exertion (“mild to moderate”, “passive, light effort” or “active and vigorous”), as one of their tracked activities.

And what happens when unscrupulous users trick their device into counting steps by attaching it to their dog’s collar, their ankle, a metronome or even a power saw – or simply hand it to a fitter or more active friend or relative? In China, there’s even a rocking cradle to which you can attach your phone, thereby artificially inflating its step count. Researchers say such hacks are rare, but you can imagine them appealing to a cash-strapped couch potato on an incentivised premium.

Australian researcher Deborah Lupton. Photo/Supplied

Good in theory

Wearable fitness trackers sound so good in theory. They remind us when to get up and move, encourage us to reach our daily step goals, measure our heart rate and monitor our sleep. What could possibly go wrong? If you could afford one, why wouldn’t you give it a go?

Australian researcher Professor Deborah Lupton can think of a number of reasons. Lupton, of the University of New South Wales’ Social Policy Research Centre, is one of the world’s leading investigators into the effects of fitness trackers – and their potential for misuse. She told the Listener that even if she did want to start measuring herself now, she would not because of concerns about data privacy.

“We can see this ‘function creep’, say, with life insurance companies. What started off as people doing it for themselves because they wanted to improve their health, fitness and sleep is now moving into domains where third parties have an interest in your data, whether it’s for such things as insurance or just making money out of you by selling your data to others or exploiting it to target advertising. That’s expanded exponentially in the past few years.”

Even anonymised data can become identifiable if different data sets are linked, she says.

In April, Lupton was the keynote speaker at the World Congress of Sociology of Sport, in Dunedin, where she outlined the pros and cons of fitness trackers. For users, pros included better knowledge and awareness of their bodies, a feeling of being more in control, improved fitness, performance, confidence, health and well-being, fewer visits to the doctor and better social connection and motivation. Cons included information overload, poor device design, loss of face-to-face support and expertise, breaches of data privacy and security and an over-reliance on self-help and self-responsibility. She says people give up on wearables if goals feel unachievable, reminders become annoying or they lack social support.

Some of the most enthusiastic users of fitness trackers such as Fitbits are middle-aged and older women, probably because walking is their preferred form of exercise rather than activities such as cycling, says Lupton, “which seems to be a middle-aged man thing”. In Australia, about one in five adults owns a smartwatch or fitness band. But her research has found women are often frustrated by the design of apps or devices that don’t cater for their needs.

“Women with babies and young children say that before they had children they were using their Fitbit actively and enjoying it. But as soon as they had a baby, they didn’t want a fitness tracker. The app was nagging them to take steps they didn’t have the time or energy to take. It was guilt-inducing. They knew they had terrible sleep and they didn’t need their tracker to tell them that. They wished there was a function you could put into it to say “I’m pregnant” or “I’ve just had a baby”, so the device would stop nagging them based on these pre-established goals and norms that your Silicon Valley dudes have programmed in because they are not thinking about using this device in those situations.”

Dr Mitesh Patel. Photo/Getty Images

“Invisible labour”

Many devices also fail to measure “invisible labour”, and this seemed to particularly apply to women – for example, because of the way steps are counted, using algorithms that include arm movement, trips around the supermarket pushing a trolley or walking the baby in a pram often aren’t detected.

Lupton says some teachers are now using heart-rate monitors and fitness trackers on students in phys-ed classes, “to encourage them to run faster or see which child in your class is putting in a bit more effort and not hiding behind the toilet blocks. Teachers think it’s a great way to motivate and encourage students and keep an eye on them, but when we asked them if they ever thought about data privacy on behalf of their students, they hadn’t.”

University of Pennsylvania researcher Dr Mitesh Patel, an expert in how wearable devices and smartphones can be harnessed to change patient and doctor behaviour, and who’s worked with Vitality developers in the past, is generally enthusiastic about their potential, but told the Listener that devices will often fail if used in isolation. Schemes such as the insurance incentives may change that.

“Now, there’s a mechanism to give them to people who have higher risk – who might be diabetic or need to lose weight – and combine a financial incentive for behavioural change. It’s definitely a step in the right direction.” But the problem remains that those who need the devices the most aren’t the ones who are using them. Without other incentives, a third of wearers abandon their trackers within six months.

But research by Patel and his colleagues has shown how financial incentives – if framed as a loss rather than a gain – can have a big effect. They followed 280 overweight or obese adults and randomly assigned them to one of four groups using a smartphone to track their steps, with a goal of 7000 a day. The control group received a text message each day, either congratulating them for achieving the goal or pointing out that the goal wasn’t met. The other participants received a financial incentive: getting either $1.40 a day for meeting their step goal, entry to a lottery, or losing $1.40 from an upfront pool of $42 each day if they failed to meet their goal. Those in the “loss-incentive” group achieved their step goal 50% more than the other groups.

In reality, however, Patel says such incentives are often tied to health-insurance premiums and become invisible, buried in a pay cheque or going directly out of a bank account – or even coming at the end of the year. Without financial or social incentives, such as workplace or friend-group challenges, users often abandon their devices.

“You can’t expect the devices on their own to motivate people who aren’t that motivated or have chronic conditions. We need to combine the technology with behaviour change and get them into the hands of patients who can benefit the most.” When his group gave a wearable device alone to patients who’d been discharged from hospital after a heart attack, the strategy failed. But those who received the device and a $2 a day loss-framed incentive walked 160km further in the six months after the heart attack.

But just how many daily steps are required to be life-extending is open to debate – do we really need to get to the 10,000 a day recommended by the World Health Organisation and cardiac specialists? In a study published by Harvard Medical School researchers in JAMA Internal Medicine at the end of May, data from 18,000 older women in the US Women’s Health Study showed that those who walked about 4400 steps a day lived longer than women who averaged just 2700 steps, but there was no reduction in mortality rates for those who averaged 10,000 steps rather than 7500.

Waikato researcher Holly Thorpe. Photo/Ann Huston/Supplied

“Healthy behaviour change”

Professor Holly Thorpe, from the University of Waikato’s Faculty of Health, Sport and Human Performance, says she and post-doctoral student Marianne Clark wore fitness trackers for several weeks at the end of last year for a study analysing whether literature about the devices matched up with the wearer’s experience.

“I found myself surprised at how motivating it was,” says Thorpe. “I was in Australia for a conference and I’d been doing quite a bit of walking. That evening at the hotel I checked my device and I was almost at my 10,000-step goal at 10pm after a very long day. But I went outside and up and down the stairs to make sure I got my steps. When I got the vibration saying I’d achieved it, I was quite happy with myself. It got me.”

Although that appears to be a good thing, Thorpe says it could work both ways. “Do you need at the end of a very busy working day to feel that you haven’t quite got your 10,000 steps?” She says although many women appeared to find a lot of support and motivation in the digital communities that grew around the technology and were drawn to the data, others couldn’t care less.

“If you are driven by gathering your data and you go for walk, run, surf or cycle without your tracker on, has it really happened? Does it change the joy of movement, going out for a run, feeling the wind in your hair, shaking off the day? If you enjoy wearing and seeing the data, then you should use one. But if you feel controlled by it, or the device is controlling your behaviour in problematic or obsessive ways, then it’s probably best not to. Know the limits of the data, where it might end up and how it might influence your feelings about yourself and whether you had a good day or a bad one.”

Public-health physician Dr Robyn Whittaker, from the University of Auckland’s National Institute for Health Innovation, researches programmes using mobile-phone prompts to change behaviour. One of the most successful has been text messaging for smoking cessation. “There’s something about frequent messages sent unprovoked to your mobile that works really well to support healthy behaviour change.”

She says the evidence isn’t there yet for apps or wearable sensors, but Fitbit’s regular reminders to get up and move, could work this way. “People who buy a Fitbit are reasonably motivated in the first place, so that’s a good thing, but it’s only that population it’s going to work for, and for probably a short period. A lot of these things don’t have great stickability – there aren’t a lot of reasons for people to keep going back to look at it, whereas messaging is an unprompted reminder and you can’t ignore it because we’re highly trained not to ignore text messages. If it’s a notification from an app, it’s really easy to turn those off.”

Dr Robyn Whittaker. Photo/Rebekah Robinson/Listener

Modest deviations

Auckland cardiologist Dr Patrick Gladding, who guesses nearly 50% of his patients wear fitness trackers, says he’s already seen about half a dozen people who’ve gone to the doctor because of unusual heart-rate readings on their Apple watch. Mostly nothing is amiss, but one of his patients is still having tests. He says suggestions by tracker companies that the devices are improving health are premature. Patients with atrial fibrillation often monitor their heart rate on a wearable device. “They’re not all that accurate, but it’s sort of a guide. I don’t think they tell you anything very useful about heart health if you’re well and have a normal rhythm. To some extent, the rate at which your heart beats is an indicator of fitness, but that’s a pretty loose thing.”

Gladding says I shouldn’t get too concerned about a moderate change in heart rate after my Fitbit’s app update. Indeed, we shouldn’t really worry if our resting heart rate is 65, 75 or higher – a normal range is regarded as 60-100, but some elite athletes are in the 40s. “Everyone is different. The 60-100 range is just so people don’t get anxious if it’s 80 versus 70, because that’ll be normal for them. If you’re overweight and more unfit, it’ll be higher, but that’s a very broad generalisation. There is no line in the sand above which it is bad.”

Where there has been an abrupt change, and the reading has increased substantially – say by 30% or more – it may indicate the need for further investigation. “There are very astute patients who know themselves very well, who exercise and notice their heart-rate response to exercise has changed. They already have heart disease and they’ve come to me and it seems something has gone wrong or deteriorated.”

He says that’s more useful information than modest deviations in the “worried well”. He doesn’t recommend patients use fitness trackers, because most are not FDA-approved medical-grade devices. “It may just cause more anxiety, and I don’t have confidence in algorithms that are hidden away in company systems.”

He’s also worried about privacy issues, the extent of the surveillance of data and its potential use by insurance companies. “It’s like when people who go on overseas holidays are weighed because they’re fatter, which similarly has a degree of yuck about it. You could get to a very punitive situation where instead of providing goals and encouragement, you’re penalising people and that could make disparity worse.”

But if people want to buy a device, he wouldn’t stop them. “I didn’t realise how many steps I took at work until I got my phone app and then I was horrified. Now I take the stairs instead of the elevator. In the weekends I’ll easily make 10,000 steps, but during the week it’s 2500-3000. As a junior doctor, I walked 7km a day and wore out a pair of shoes a year. My shoes don’t wear out anywhere near as quickly now.”

The app update

I still haven’t got to the bottom of my Fitbit’s behavioural blip. I tweet-messaged the company’s support service for help. It wasn’t the Fitbit, they said. It was me. The app update hadn’t altered the way heart rates are measured, and I’d probably just changed the way I was wearing it. (I hadn’t. Nor had I changed my routine.) What I have done, though, is reassess my relationship with my Fitbit and my dependence on it. My former lover has now been friend-zoned. “It’s not you,” I said, “it’s me.” But I didn’t really believe it.

Lee Jones.

How we’re using them

Who’s using fitness trackers? Often it’s those who are highly motivated – yet want to be kept honest.

Gym owner Lee Jones, 55, has worked in the fitness industry for nearly two decades. He has a degree in exercise science and has worn a tracker for about eight years. “I was an early adopter, but I do like technology. It keeps me accountable and honest about what I’m doing. I’m not fixated on it, but I do look at it as an indication of where my health is. I look at how far I’ve walked, because it’s very easy to think you do more than you actually do. They’re also becoming much more accurate for measuring sleep and I look at my deep sleep times as being more beneficial than my disrupted sleep. I can look at when my sleep was restless, and what was going on in my life at that time and say I was pretty stressed and that probably accounts for it.”


Elaine Parnell.

Elaine Parnell, 42, teaches English as a second language to adults. Her Fitbit was a Christmas gift from her husband. “The lady in the shop said, ‘Do you not think you should ask her first?’ He thought it would be something I’d enjoy. I do enjoy it, but it doesn’t mean I take more steps. I have a goal of 10,000 a day and I meet it about twice a week. When I first got it, if I was on 9000 or so, I’d go out and walk up and down some steps until I got there, but I don’t any more. My 13-year-old daughter was given one a few months ago. I wasn’t that happy, because she’s a competitive gymnast and there’s enough pressure on body image at that age. But she’s organised a weekly family step challenge and our scores go up on a whiteboard. I haven’t got the Broken Laces Award yet for the lowest number. I tried logging my food, but it was hard work. I’ve noticed it doesn’t record steps when I push a trolley around the supermarket, or record when I go cycling or to the gym.”


Jill Thomas.

Retiree and former marketing consultant Jill Thomas, 65, got her Fitbit a few years ago as an incentive to keep moving, given she spent a lot of time at her computer. “When it reminded me, I’d get up and go up and down stairs or do some star jumps. I was training for a half marathon and I’d do 10,000 steps a day easily. My step goal is set at 10,500, and I typically do that and more. If I’m hiking, I do 20,000. The only time I’ve used it competitively is when we had a work step challenge and we had competing teams. Then I’d be still stepping in front of the TV. The device doesn’t measure my heart rate – I didn’t want all the bells and whistles, I just wanted my step count. I’m not hung up on it; it’s not a huge part of my life – not like my phone.”


Dean Teiho.

IT manager Dean Teiho, 53, got his tracker in 2015 as a fitness and weight-loss motivator. “As the months went on, I could start to see the pattern in workouts and knew if I pushed myself, I could burn more calories and have a little more food. I was on a fairly strict diet and I’m sticking to it. I know what works, and it’s helped to keep me in line and be accountable. I track my data daily. Steps aren’t important, it’s the amount of calorie burning I do – higher intensity for less time. I go to the gym every day and work out for 45 minutes. If people understand what they need to do to reach their goals, this will help.”


Swati Vadgaonkar.

Kitchen designer Swati Vadgaonkar, 54, got her Fitbit as a Christmas gift from her husband about two years ago. “I’d done the Auckland Half Marathon the previous year, but I wasn’t fit. It was to motivate me to get fitter. And it has. My doctor was going to prescribe blood-pressure tablets, but I told him, ‘No, I will control everything I do and come back to you.’ After six months, I didn’t have to. Because I sit at my desk a lot in my job, the Fitbit reminds me to get up when I’ve been sitting too long and that I have 10 minutes to achieve that hour’s step goal. I also use the calming app, which tells me how to breathe when I’m stressed.” She’s set a daily step target of 8000 (about 6km) and achieves it four or five times a week, with longer walks on weekends. “I was definitely less healthy before and less motivated to move. When I’m driving home and stuck in traffic and it tells me I need to do another 100 steps, it reminds me I must go for a walk in the evening. It adds to my guilt, but I don’t find it stressful. It’s between the tracker and me, and it stops me having another piece of chocolate.”

This article was first published in the June 8, 2019 issue of the New Zealand Listener.