How to use a fitness tracker

As soon as I awoke, I checked that the fitness tracker was still in place, then scrambled desperately for my phone. I had to know if something had changed. I consider myself a pretty healthy person and after getting the fitness tracker (a Garmin smart watch) earlier in the week, I’d been smugly satisfied by the positive metrics, except for one. I unlocked my phone, swiped through app icons and my shoulders sagged. Evidently, another night of restless, light sleep and a poor sleep score. Gutted.

I share this story because fitness trackers are not for the faint of heart. Wearable health tech is transforming our relationship with our bodies. It will, I believe, become as revolutionary to healthcare as the discovery of penicillin. Healthcare is going digital, moving away from hospitals and clinics and to the wrists and pockets of the public.

But is it obvious how to use a fitness tracker to best effect? It took my partner to eventually point out the obvious to me: the biggest thing affecting my sleep was my anxiety about my morning sleep score. Sounds ridiculous doesn’t it? I ditched the Fitbit at night and slept well ever since.

So do fitness trackers always show us what we expect or want to find? Do they always live up to the hype? And crucially, do we know how to use the information they give us? Read on for my thoughts on the key questions to ask to get the most from your new fitness tracker.

 

Are you ready to change?

Just because someone has a fitness tracker, does not mean that they’re ready to change what they do. Some will be drawn to trackers simply by curiosity or trend-following but may not be aware of any unhealthy behaviours they want or intend to change. Others will already be living a healthy, active lifestyle, and see trackers as a motivational tool for setting new targets and exceeding them.

The Stages of Change model (by Prochaska and Diclemente) describes 5 different stages people find themselves in when changing a behaviour. It can be useful to honestly consider which stage you may be at, so that you can set reasonable expectations for what you hope to achieve. The stages are:

Pre-contemplation

As far as you’re aware, you’re health is peachy. You’ve never considered there may be something to work on. For you, approach your fitness tracker with an open mind. See what insights it begins and it may be that you move into…

Contemplation

Darn. You’re now aware there’s a hiccup. It might be excess calories, a low step count, a high resting heart rate or poor sleep. It’s good that you know – you’ve just got some tough thinking ahead of you. What would it mean for you if you changed? What would it mean if you didn’t?

Preparation

Okay, so you’ve decided you want to do something to improve your health. That’s why you got the tracker right? Or your spouse bought it. You need to build momentum slowly. Use your tracker to set small, achievable goals that will build your confidence and your commitment.

Action

Well done! You’re on your way to living a healthier lifestyle. Play around with the tracker. Feel the satisfaction of meeting your goals. When you meet them in one area, say diet or exercise, look to improve another area, maybe through sleep, stress reduction or water intake.

Maintenance

Perhaps the hardest stage of all. You’ve made progress but you know consistency is key. You need to keep it interesting. Set yourself challenges, adventures (some will guide you through virtual running or cycling routes) or compete with friends. 

 

What metrics are you interested in?

Once you know what Stage of Change you fit into, you’ll find it easier to figure out what type of information is going to be most useful to you. Fitness trackers initially gained their fame through tracking steps against a daily goal of 10,000. This number is somewhat arbitrary but step counting remains a useful measure of how active or sedentary we are during the day.

Most trackers will also monitor heart rate and from that, estimate a range of other parameters. Fitbit will use your heart rate to estimate a ‘stress score’, directing you to guided breathing or mindfulness exercises if the score creeps up. Garmin will use heart rate, and other metrics, to provide a range of scores of interest to athletes. This includes information on V02 max (a measure of cardiovascular fitness) and predicted recovery times.

Competing fairly with a fitness tracker

However, in a bid to level the playing field when friends wish to compete, some wearables now aim to measure exercise effort as well. MyZone chest straps award different numbers of effort points, or MEPs, depending on what % of your maximum heart rate you’re exercising at. Fitbit’s new ‘Active Zone Minutes’ and Google’s ‘Heart Points’ do similar. This means that a Tri-athlete can still compete with their friend doing the couch-to-5K. As long as both are still pushing against the limits of their fitness and increasing their heart rate, it doesn’t matter how many kilometres each can run, swim or cycle.

Finally, if you want simply to track calories, weight, water intake or your mood, you may not need a fitness tracker at all. Mobile phone apps abound which can track these for you, as long as you’re happy to enter the data yourself. To date , there is no wearable device which can track these metrics without some manual data entry.

Fitness data that’s missing the ‘Why’

Fitness tracking and wearable devices have entered a space race. First mover advantage appears to have overtaken sense and even usefulness. I still remember the first patient who visited me to discuss his heart rate variability, as reported by his watch. A tall, slim, healthy triathelete who tried to accept my reassurance, but couldn’t quite  ignore the sense that his watch had found something seriously wrong. The problem is that wearable devices are giving us insights with very little guidance on how to use them. It’s the equivalent of a surgeon giving you a scalpel and just pointing to your appendix.

Returning to the introduction, my poor sleep stats were exacerbating my problems. The app I used had a few suggestions for how to sleep faster and for longer but I was already doing that. I needed to improve my sleep score. How do I boost my REM sleep? How do I spend less time in light sleep than deep sleep? Even the latest sleep science is struggling to explain this. So why track and score it?

Does your fitness tracker do what you think it does?

The latest release of new features is even more worrying. Oxygen Saturation (Sp02), the % of haemoglobin in your blood that is full of oxygen, is a new feature for many devices. In a medical setting, it is used for detecting and monitoring a range of conditions, from Pneumonia to COVID-19. Is that why fitness trackers use it? No.

Many will have disclaimers advising that their Sp02 monitoring is for ‘wellbeing purposes’ only. What these wellbeing purposes are is anyone’s guess. Some companies have argued that drops in Sp02 at night can help detect Sleep Apnoea, a condition that affects breathing whilst we sleep. This sounds positive, on the face of it. But how many healthy people without sleep apnoea will be needlessly alarmed by the advice of their fitness tracker? How many will then seek medical appointments and undergo further tests, unnecessarily?

ECG, or heart trace, recordings carry similar risks. A medical ECG will involve 12 different cables, stuck across the front of your chest, to detect the conduction of electricity through your heart muscle. It can show a doctor if there are problems with the rhythm or regularity of electrical pulses, the conduction of electricity or even the balance of chemicals in the bloodstream. In a fitness tracker though, the equivalent of just one cable is used. This can give some insights on the rhythm of the heart but it is limited and will only detect one or two specific abnormal rhythms.

 Conclusion: how to use a fitness tracker?

Every quarter, the wearables market seems to take another leap into the future. I’ve no doubt that in just a few years, we’ll have devices that come close to replicating those used in our hospitals. We may see devices that can automatically monitor blood sugar levels, blood alcohol level, early signs of infection, calorie consumption or maybe one day, early markers of serious disease, like cancer. Have no doubt that the medical profession is gearing up for this too. We are just a few steps away from merging wearable data with medical records.

The future is exciting. But for now, it’s important not to be swept up by the hype. The question that will only become bigger, is not “what data can it give me?”. It’s “what do I do with that data?”. So start with considering your goals. Where do you sit in the cycle of change? Which features would be most helpful in progressing your fitness and health goals?

Once you know that, you can choose a device that’s right for you, that measures exactly what you need it to measure and that doesn’t keep you up at night.