[Brian Bauer]

what is your MAF number? i.e 180-age?  when you slowly jog for 1 mile, what is your average HR?  how much are you exercising per week? run volume, bike volume, walking, etc? do you consider yourself to be healthy with some fitness? even with all of the data you are sharing, without knowing something about you, its not possible to offer an opinion on your negative drift question.