As well as the usual sleep quality insights, Polar Ignite also offers recovery insights, which measure how well you've recuperated from stress and training throughout the day. Using an optical sensor in the watch, the feature measures the status of your autonomic nervous system, which reveals how recovered you actually are, regardless of how well-rested you feel. The watch then combines this data with FitSpark, a daily training guide, for personalized cardio and strength training based on what it believes your body is capable of.

The watch comes with a host of other features, such as guided breathing exercises, run and swim metrics, calorie tracking and so on, but it's certainly its recovery insights function that sets it apart from other wearables. Having a lousy workout can be pretty disheartening if your tracker is urging you to go for it all guns blazing -- the Polar Ignite at least recognizes when you're at the top of your game, and knows when to give you a break if you're not. The watch costs $230 from Polar.com, with optional silicon accessory bands costing $25.