Auto/manual lap; auto pause; target alarm setting (time, calories burned); training display customization It was a similar story for resting heart rate where readings were around the 80bpm mark, which is someway off the more reliable 40-45bpm average being dished out by the Enduro. When charged about eight hours every day under indoor fluorescent lighting (500 lux), and charged at window side on a sunny day for two hours in a week (10,000 lux). Training Mode (intermittent GPS measurement) + heart rate monitor function: Maximum of about 18 hours That’s because it has a solar panel integrated directly into the display. As long as your watch is exposed to light, it’s charging – and that means that everyone but those on a regular schedule of GPS-using ultramarathons will find that the charge cable can largely be forgotten (although try not to lose it because it’s a proprietary USB cable so will be a pain to replace).

I’ll cover some of Casio’s special design choices in a minute but let’s paint the picture by setting the expectation that this might be a ground-breaking model in a few ways that could send ripples through other parts of the sports & outdoors market. Minimum heart rate/maximum heart rate; heart rate graph display (when heart rate measurement is continuously ON) Training Mode (continuous GPS measurement) + heart rate monitor function: Maximum of about 14 hours The G-SQUAD PRO GSW-H1000 runs a hybrid operating system that combines Casio's own software with Wear OS. The result of this tinkering is not a seamless user experience, especially if you haven't used a similar watch before, which I assume will be the case for most people. We had constant struggles trying to connect and sync the watch to the Android app even after Casio rolled out an update to the app to issue a fix for those connection issues.

Background: Casio & Smart Watches

Need a running watch that's equally as bulky as the Casio GBD-H1000 but maybe a bit more competent? Try the Garmin Enduro for size. The Garmin Enduro is a future-proof GPS multisport watch that has an insanely-long battery life and some trail running-specific features that even non-trail runners will appreciate. On the left of the case, you'll find the outdoor sensors that are onboard and the charging port, which mirrors the setup of how you charge Casio's ProTrek smartwatches.

Putting the watch through its paces, with several GPS workouts and notifications switched on, I was able to get roughly seven days of use on a single charge – far better than what you’d expect from a Wear OS smartwatch or even an Apple Watch. In theory, the GBD-H1000 can determine VO2 max, training status, training load, recovery time, training effect and calories burned during training using an algorithm from Firstbeat Technologies, the same tech used in the Garmin Quantix 6, Montblanc Summit 2, Huawei Watch GT 2e and more. In reality, since the heart rate sensor is a bit off, the suggestions about most of those stats are rough estimates at best.Maximum value: 220bpm; heart rate; target heart rate setting function; heart rate zone graphic display; heart rate transition graph: maximum heart rate/minimum heart rate This, combined with power-saving functionality that will automatically dim the display when in the dark between 10pm and 6am, means that I’ve only used the charger twice since getting my review unit. The first of these before I realised it was basically unnecessary, and the second when I inadvertently left the GPS running overnight while trying to note down the various metrics for this review. Even then, it wasn’t dead the next morning – just on “low battery”. Outstanding. Where Can I Wear It Without People Laughing At Me?