We investigate the influence of the magnetic field of the experimental storage ring (ESR) at GSI on the periodic time dependence of the orbital K-shell electron capture decay (EC) rates of the H-like heavy ions. We approximate the magnetic field of the ESR by a homogeneous magnetic field. Unlike the assertion by Lambiase et al (2008; arXiv:0811.2302 [nucl-th]), we show that the motion of a H-like heavy ion in a homogeneous magnetic field cannot be the origin of the periodic time dependence of the EC-decay rates of the H-like heavy ions.