TomTom has always made pretty decent running watches and fitness trackers, but despite several revamps its app has never been all that useful.
It's hardly alone in that – most fitness wearables are great at gathering data about your activities but poor when it comes to telling you what it means and what you should do about it.
With Fitness Age and personalised workouts, announced today at IFA 2017 in Berlin, that looks set to change.
First up, Fitness Age compares your cardio data, taken from your TomTom device's heart-rate monitor, to the population at large to give you a simple indicator of your overall fitness.
It's based broadly on VO2 Max, which is a measure of how well your heart can cope with intense exercise, which is widely used by sports scientists.
Say you're 36. If your fitness age is 28 – ie, the same as a fit 28 year old – then clearly you're doing well. If it's a bit higher then maybe you should put in a bit more effort running, cycling or at the gym.
That's not entirely a new idea. What's potentially really useful is that the TomTom app will now suggest what you need to do to improve your Fitness Age.
It breaks your activities down by how useful they are in improving health, using a star system. So a run will generally be worth more stars than a walk, an intense gym session may be worth more than a slow bike ride, and so on.
It'll also tell you when you should be putting in some extra exercise, and how hard.
That's a big, big step forward from just logging your runs and telling you how many steps you've taken.
If you earn more than 100 stars per day, you're maintaining your fitness, whilst getting over 500, three times per week, should mean you're improving. The app will tell you when it's time to get active and how hard you need to be working.
Interestingly, if your Fitness Age is significantly higher than your actual age, TomTom won't actually tell you what the age is, as that could be too demotivating. Instead it will just strongly recommend you get some more miles in.
A further development of this is Personalised Workouts. These use cardio zone training to target five levels of intensity, from relatively sedate 'Fat burn' to limit-pushing 'Speed' and 'Power' workouts.
Feedback from the app then guides you to work harder (or slow down) to reach and maintain the right heart rate while exercising. At present this is limited to bike and running workouts, although it could be extended to gym work, cross training etc, in future.
There are some caveats to all this. VO2 Max, which TomTom uses to estimate Fitness Age, is a useful measure, but it is primarily a guide to how good your heart is at working absolutely flat out, which is not a level of intensity the average person necessarily needs or wants to hit.
Cardio zone training is great if you know what your personal heart-rate zones are and can adjust your device accordingly – they vary according to age, fitness levels and even just your genetic makeup.
Since TomTom doesn't seem to be allowing this with its Personalised Workouts, some users may find they benefit less than others from its advice.
However overall, this is exactly the direction fitness wearables should be moving in: giving actual, useful advice, and actively helping wearers get fitter over time.
Interestingly, TomTom isn't launching new hardware alongside this app update, which will roll out to its various existing devices with heart rate monitoring during September: TomTom Runner 2, TomTom Runner 3, TomTom Spark, TomTom Spark 3 and TomTom Adventurer.
We'll have a review ASAP, because this seems genuinely cool.