personally between the morning (out of bed) and the evening (before going to bed) I lose on average 2 cm. I lose the first cm very quickly after a few minutes then the rest happens throughout the day. What I told myself is that if we manage to straighten our back as much as possible and possibly with sport, strengthen our legs, this could perhaps increase the size in the morning and at worst maintain the size during the day. however I think it must be very long and a weekly routine which may not be worth it.