Going running? Well, if you’re serious, you need to monitor your activity. True, there are fitness wristbands like the Nike FuelBand SE which can helpfully keep track of your movements. And the Nike will also count your steps, the calories burned and more.

But for a higher level of accuracy, a gadget designed to specifically track your runs is necessary. Last year, TomTom released a runner’s watch which even included a ghost - a record of previous runs that appeared on the watch for runners to try and match or beat.

All very well, but the device itself was met with a mixed response, criticised for the way data was downloaded and the time it took to lock on to GPS. It was partly because runs were measured in relation to satellites that it was so accurate but cooling your heels waiting for these to kick in wasn’t great.

Now, TomTom has released a new watch that does everything last year’s model did but also measures your heart rate. This is a useful extra that really helps you get a hold on your overall fitness.

It works by shining a light at your skin and using a camera to measure the way your skin colour changes and using this to calculates how fast your heart is beating. Other gadgets do this – there’s even an iPhone app that achieves it - but the difference here is the level of accuracy. Testing it alongside professional, medical equipment revealed a consistently precise readings.

TomTom’s watch measures distance accurately, too, thanks to that GPS sensor which, unsurprisingly for TomTom, is built in again here. So running outside is calculated with great meticulousness. Mind you, you can also set it to work when you use the running machine, though here the calculations are made according to wrist movement rather than GPS.

To work at its best the TomTom Cardio has to be quite tight, so it can leave impressions on your skin afterwards. And the user interface still has issues. What’s more, this is not a watch that looks fancy or elegant – the bright red rubber strap reveals this as a gadget even before you see the digital screen.

Data is now transferred to your iPhone by Bluetooth – an Android app will follow – and the GPS lock is now faster, though still noticeablely laggy. Still, it’s considerably under a minute now.

Overall, this is a successful gizmo that will help you measure your runs perfectly and tell you when you’re doing too much. Or too little.

£279, www.tomtom.com