Built specifically to need the under the hood improvements in Windows Phone 8.1, we at last have a Fitbit client for the OS, announced today (presumably proudly) on Microsoft's site. Fitbit is a range of 'wireless activity trackers', in case you hadn't heard of them.

From the launch post on the official Windows Phone blog:

Fitbit is launching their native app for Windows Phone 8.1 today that brings direct mobile syncing (via Bluetooth 4.0). Devices running Windows Phone 8.1 will now have instant access to up-to-date stats from Fitbit’s wireless activity trackers like the Flex, One and Zip. Fitbit’s wireless activity trackers track health and fitness metrics like steps taken, distance traveled, calories burned, active minutes, floors climbed and sleep quality. With their wireless activity trackers, Fitbit wants to inspire people to lead healthier and more active lives. I am nearing my two-year mark as a Fitbit user so I’m pretty excited about their app!

  

The client includes:

• Real-time stats: Automatic and wireless syncing for all Fitbit activity and sleep trackers through Bluetooth 4.0
• Fitbit on your Start screen: Pin the Fitbit Live Tile to your Start screen and quickly view your step count
• Stay on track: Real-time and historical stats in easy-to-understand graphs, to help track progress and set goals
• Log more than activity: Recently enhanced food database of more than 350,000 foods with accurate nutritional data for faster, better food-logging and calorie coaching
• Get motivated: Fitbit's motivational social tools like notifications and badges, to help reach target goals
• Stay social: Ability to challenge friends and family with leaderboards, direct messages, cheers and taunts

You can download the Fitbit app today for free from the Windows Phone Store and start syncing your Fitbit wireless activity tracker.

Assuming you have WP8.1. The catalog of apps and functions which require this release is growing fast, so I really hope that Microsoft accelerates its Cyan upgrade programme, lest millions of users start to get more than a little frustrated, confused, or both....!

This availability may get your hopes up of general smartwatch clients being possible, but access to Windows Phone 8.1's Action Center isn't full enough get, so don't hold your breath. A smartwatch client will require the next version of Windows Phone at the very least, and will probably need Microsoft to get actively involved, perhaps by producing its own accessory.