In his paper, Chou et. al., 2010 has demonstrated that an atomic clock at the height of our head ticks faster than an atomic clock at the height of our feet. I was thinking that one electromagnetic process can be substituted with any other - so that corresponding atoms in our head tick faster than those in our feet so that our head ages faster. If I however simplify the electromagnetic process to a single oszillating field, I concluded I would see the field at my head being blueshifted in comparison to my feet. Faster ticking of (biological)clocks = faster oszillation = more energy/mass (we have to put work in to lift our head in a potential). The scenario for outgoing light would of course be different as light has to fight the potential - it gets redshifted as we all know. My question now is: Is the head and foot scenario as I understood it in accordance with SR? Does SR state that our head ages faster because it is blueshifted? I am concerned and confused that the effect of time-dilation is attributed to redshift? But I think the experiment by Chou reveals reality? Or is SR not applicaple here? I was thinking of it in the way that when you sketch a light clock with constant velocity the redshift is an 'apparent' or 'relative' effect. However acceleration (or the equivalence in a gravitational field) will induce real changes. And doesn't energy input cause blueshift? So I conclude that energy input results in 'real' bueshift of everything and with that in faster aging. I'm not very advanced in my studies yet, but have been thinking about this topic since a year now. So I thought I ask others. Thank you in advance.