I don't sleep much. I'm healthy, I'm fit. I run, I ride, I hike. But I've never been a long sleeper. if I get a solid five hours of sleep I'm good to go for any given day, and if I get six I'm thrilled and on top of the world. Yet my Forerunner 955 sees those five hours and says my "body battery" is drained, my training readiness is low, etc. Obviously I listen to my body more than I listen to my watch, but still, it would be much nicer if it told me something closer to how I was feeling, and to my specific physiology. I'd have thought that over time the watch would establish my normal sleep baseline and then go from there, so that if it sees that week after week, month after month, I'm averaging five and a half hours of sleep a night, then that's my baseline and it needs to calculate my body battery and training readiness against that. But no - it's still "penalising" me. So if it can't auto-calibrate a baseline, how about letter the user input their own baseline? Hope Garmin product people are reading this...