Subjective, self-perceived data and monitoring should always prevail over e-data and tracking, although you can use the logarithmic metrics to establish patterns and references which can be used in tandem with your self-perceived metrics. Resting Heart Rate, Respiration ( breaths per minute ) and HR zones are the parameters that I pay attention to. Ultimately, the body is the arbitrator not the wearable! According to my Garmin, I should have rested last Sunday ......instead of doing the Mornington to Mt Martha half-marathon! Cheers.