It has been demonstrated that the catalytic hydrogenation of CH3, C2H2 and CO that takes place on Ni single crystals, occurs almost exclusively by subsurface atomic hydrogen (H), indicating the importance of bulk hydrogen in heterogeneous catalysis. Here, we use Density Functional Theory (DFT) calculations to investigate the ability of, the H induced, 1x2 reconstruction of Ni (110), to adsorb additional H in the subsurface area and we compare with the clean surface. Our results suggest that the formation of the Ni 1x2 phase on Ni (110), results in the creation of stable subsurface adsorption sites for atomic H. The reversal of the thermodynamic drive on H atoms that are adsorbed on the catalyst surface, occurs during the transition between the 1x1 and 1x2 surface phases. This reversal, of the thermodynamic drive, leads to the creation of subsurface atomic H that desorbs above RT. This study provides an explanation regarding the high temperature desorption of subsurface H from Ni (110) that was reported previously in the literature and a consistent interpretation of the experimental results related to it.