As impressed as we were with the TomTom Runner and Multi-Sport, it was obvious at the time that there was plenty of room for improvement.

A year later and TomTom is refreshing its watches with the new "Cardio" versions, which bring all the familiar features of the first two but with one big added extra - a built-in heart rate monitor.

Not just that, but (so far) a highly accurate one. The original Runner and Multi-Sport could be paired with a separate heart rate monitor but wrapping that strap around yourself and pairing it with the watch was a lot of extra hassle.

Having an optical monitor on the watch not only saves time, it's also a lot more comfortable. No more awkward pad licking (you know exactly what I'm talking about).

Cardio

Like the original sports watches, the TomTom Runner Cardio is focused on, well, running, while the Multi-Sport throws in added features for tracking cycling and swimming. I took the Multi-Sport out for a test run for this hands on review but I'll need a bit more one-on-one time with it in order to test out its full functionality. The good news is that first impressions are solid.

As you've probably guessed from the photos, TomTom hasn't gone for anything radically new in design. The new watches do come in a nice new red outfit though, and you can opt for either a red and black or a red and white version.

The main watch unit is now held in a lot more securely (a gripe I had with the first watches) so it'll no longer slip out unless you apply a fair bit of pressure.

Cardio

Witness the fitness

But enough on the cosmetics - how good is that heart rate monitor? First thing, in order to get the monitor working you need to make sure the watch is strapped snugly above the wrist bone.

This ensures it will get a clear reading of your pulse, which it does through two green LEDs on the back that calculate your heart rate by detecting changes in blood flow. It's pretty cool stuff.

You'll want to make sure the watch is tight enough to prevent it moving about on your workout. Luckily the watch fits comfortably around the arm so that shouldn't be much of an issue, but letting it slip down will mean a loss of accuracy.

Cardio

I found that it didn't take long for the watch to find and display my heart rate but there were a couple of attempts where it took a minute or two. Once it's going, the reading will be displayed on screen and change in real time.

On my test run I strapped last year's TomTom Runner onto my other wrist and strapped a heart rate monitor to my chest so I could compare the results. As it turned out, the readings were consistently close and often identical (the Cardio watch tended to be a couple of seconds behind in bpm adjustments, which I would have expected anyway).

Cardio

But that wasn't enough assurance for me, so I also tested the Multi-Sport Cardio's heart rate monitor against a hospital ECG machine. Once again, the results were impressively in sync.

The new monitor also means you can train in your optimal heart rate zone - easy, fat burn, endure, speed and sprint - and the watch will alert you if you need to speed up or slow down.

What does seem to still be an issue with the watch is the time it takes for the GPS to lock. With the original Runner I found this was something that improved over time but it really depends on where you live.

Anyone with a vague notion of what GPS is (needs to see the sky to get a look at the satellite signal, compared to phones which can use Wi-Fi and cell towers to help out) should accept they can't get a lock inside a house so it means a bit of loitering on the outside pavement while it makes the connection.

It was the same deal with the Cardio on my first attempt, although I found that it took just under a minute to lock, so that wasn't by any means dreadful.

Juice up

A TomTom rep told me that I'll get 8 hours of full usage from the watch, less than the original Multi-Sport's 10 hours.

It might not sound like a lot but this isn't a smartwatch that you'd wear outside of training - it's far too chunky for one thing. This is an exercise companion that you'll strap on when you stick your running shoes on and slip off at the end. Still, you'll have to wait until the full review to see how the battery truly fares.

Cardio

As for syncing all that lovely data at the end of a run, owners of the original Runner or Multi-Sport will know that TomTom recently enabled Bluetooth syncing between the watch and the iOS app (Android is still MIA) and this means your heart rate data will also now be transferred over quickly with the rest of your workout stats.

Cardio

Perhaps the biggest sticking point I have with the Cardio right now is the price: £249 ($269, around AU$291) for the Runner and £279 ($299, around AU$324) for the Multi-Sport. Heart rate monitor considered, the hike on the price of the first watches is understandable (remember, we have GPS in here too).

But at those prices TomTom is going to have a tougher time going against the incoming £180 Samsung Gear Fit, which also packs a heart rate monitor. Then again, Samsung's fitness offering lacks GPS, which is something that may discourage the true running enthusiasts. We'll just have to wait and see.

Early verdict

TomTom's 2014 refresh is extremely welcome, and proves that the sat nav company is getting more serious about fitness.

The heart rate monitor is impressively accurate so long as it's positioned correctly and the watch itself is comfortable as ever. QuickGPS still seems a little slow but that will hopefully change for the better after a few runs. So far, the vital signs are good.