The Bluetooth technology, named after the Viking ruler Harald Bl├ątand who “connected” parts of Scandinavia, can be used to enhance your workout. Using this wireless technology, the Polar Wearlink + transmitter, will connect or “sync” with mobile devices. To get going you will need special mobile apps such as RunKeeper, Endomondo, CardioTrainer, SportyPal, Runtastic, Run.GPS, Sportstracklive or IdoMove.

The Polar monitors are compatible with Blackberry, Android or Windows operating systems. And Polar is one of the few brands supported by the exercise apps. Android devices and even low-end mobile units can connect to most generic gadgets with Bluetooth capabilities.

You can use your monitor with an Apple product such as an iPhone, iPad or iPod, provided that you've got the corresponding iTunes app.

The Bluetooth transmission ensures that your own heart rate signal is picked up, rather than someone else's. And Apple devices have closed Bluetooth stacks which prevent them from interacting with other devices via the Bluetooth connection.

You can wear the Polar Bluetooth heart rate monitor comfortably around the waist or your chest when connected to such devices.

Start your tracker app (such as Endomondo) and set your own target route. Your heart rate monitor will then be sending signals to your mobile device wirelessly via Bluetooth.

And you can keep on jogging, come rain or shine, because the connector is water-resistant. And when the batteries run out, it's good to know that they are user replaceable.

Another Polar product using the Bluetooth connection is the H7 Heart Rate Sensor. This product is compatible with devices such as the iPhone 4S (and possibly with Motorola Razr Droid), gym equipment and Polar Training Computers.

Since the H7 strap does not require any receiver or dongle in the iPhone, this will cut the cost of receiving heart rate data, so it might save you some money compared to traditional iPhone and Droid setups.

The H7 sensor uses a low energy system that gives you double the battery life (about 350 hours) compared to equivalent chest straps. The H7 sensor uses coded 5 kHz transmission to connect with compatible gym equipment.

The transmission range is quite long, about 11 yards (10 meters).

Since not all Android phones follow the Bluetooth Smart specifications, Polar can not promise compatibility with all such phones.

The H7 is compatible with iPhone 4S and here are some iPhone applications recognized by Polar as fully working with H7:

– Endomondo
– Cardio Mapper
– Runtastic and
– iSmooth Run

The batteries are user replaceable. If you want them to last longer you can detach the sender from the chest strap after every use.

To sum up, the Polar Wearlink + transmitter connects your heart rate monitor to mobile devices via Bluetooth which enables you to use mobile training apps such as Endomondo or Runtastic. The H7 sensor is mainly for users of iPhone 4S and works with gym equipment and Polar training computers. It provides heart rate data to your Smartphone through compatible mobile training apps without needing any dongle or receiver.