Polar has just rolled out an update to its its Polar M430 running watch, which adds 24/7 continuous heart rate monitoring.
The feature, which is already available in the Polar A370 tracker, means you'll now get an overview of your heart's variation through the whole day, seeing where you were - and weren't - active. All of this will be available to view in the Polar Flow app.
The verdict: Polar M430 review
Polar says readings will be taken "at a minimum frequency of every five minutes" during rest, which is the same as the A370, however it will up the sampling as you enter more vigorous activity.
Having these long-term graphs can help you pick out and be more aware of some of your health trends, like moments of stress throughout the day. It also makes the Polar M430 into more of a 24/7 wearable, rather than just a watch to slip on when it's time for a run.
All that said, it recently came to light that the M430 and A370 have a problem getting heart rate readings on dark skin. Our own editor Mike Sawh came across the glitch in testing the M430, and other voices have since emerged saying they've had similar issues.
Polar told us it's working on a firmware fix that will be out in early September, so the problem will hopefully be solved any day now.