TomTom has refreshed its Runner and Multi-Sport sports watches with the addition of new Cardio models, capable of measuring heart rate using a wrist-based built-in heart-rate monitor.

Pocket-lint is at the London launch where we've been quick-testing the Multi-Sport Cardio through various trials: running up stairs, ten pin bowling, even a spin class with Victoria Pendleton. No, really.

But what's new about these latest watches? The design is similar to last year's original models, featuring a four-way singular control to the base, but the key difference is the inclusion of the dual green LED monitor on the back of the main watch unit. When pressed tight to skin and it measures your active heart rate. No need for a chest strap here.

In addition Bluetooth is also on board to pair with a smartphone - it's iOS for now, Android is due to follow - for easy and quick upload of your data to TomTom MySports data site. The original models required to be seated in the provided cradle to charge and sync data - something we weren't keen on and are happy to see updated in the Cardio models.

Unlike the earlier grey, green and purple finishes, we've been handed a red and black version, the strap of which delivers a snug fit to ensure the sensor is positioned close to the skin. It's comfortable too, although does need to be quite tight to achieve active heart rate results.

Like the original model it's possible to use the TomTom Multi-Sport Cardio to measure running and cycling with GPS tracking; swimming and treadmill activity. The Runner Cardio, as its name suggests, is focused on running activity with GPS tracking.

With the latest on-board software the Cardio models promise to deliver a more robust solution than was launched back in 2013. We will detail more information in our forthcoming hands-on, taking a deeper dive into our first experience with the product.

Both products offer speed, time, pace, calories burned, heart rate and real-time training zones. It's this last one that's important as it's possible to target your optimal training zone, including alerts to tell you whether you fall in or out of your desired heart rate target. These zones are based on weight and age, divided into easy, fat burn, endure, speed and sprint.

The TomTom Runner Cardio will be priced £249, the Multi-Sport Cardio £279. Both models are available for pre-order and are due out later this month. We'll be putting our Multi-Sport through its paces to test how battery life stands up to the addition of Bluetooth and heart rate monitoring.