It's not gobblygook, it's training at a serious level. Those levels correspond well with lactic acid levels in the blood, for various types of training. I've both rowed at a high level and done tech research work with an Olympic cycling team, and this (or variants) are used frequently. HR for power (not pace etc) is a good measure of personal fitness and wellbeing (e.g. high resting heart rate means you're possibly falling ill or not well rested). However, all this doesn't matter for anyone who just wants to be healthy. That said, I defer to Garmin For proper HR smart watches and accessories, which are tailored for specific sports.