I live right next to the famous Harvard stadium stairs (see picture) which consists of 37 sections of big lunging steps up and then normal stairs to jog down. I am considering getting almost all my training volume from these stairs but have some concerns that they may cause the wrong training effects do to their short nature.
At a zone 1-2 pace it takes me approximately 40 seconds to go up and 30-40 seconds to go down each section, so my heart rate rises up to close to the top of zone 2 and then falls close to the lower end or below zone 1 every section (every 120 seconds). My goal is to build a massive base, and I am considering spending 6-8 hours per week in this Stadium doing all low intensity hiking of the stairs. As an example my workout yesterday consisted of around 2 hours of these stairs, achieving around 3000 feet up and 3000 feet down total.
Is my heart rate looking like a sign wave (from top of z2 to almost recovery hr) every 120 seconds something to be concerned about in terms of building a base? Would I be much better off finding something where I could consistently go up for hours such as a stair master (easily accessible) or a mountain (not easily accessible on week days) rather than these stairs where a change direction ever 40 seconds?
How do you expect my bodies physiological response to the training described above to differ to from the same workouts on an infinitely tall staircase?