Harold's Going Stiff (2011)

Lonely pensioner, Harold Gimble, has become the first man to suffer from a new neurological disease that is slowly turning him into a zombie-like state. Harold’s hermit-like existence is shaken up when a vivacious nurse, Penny Rudge, is sent along to alleviate his stiffness. Her ‘special’ massage techniques work a treat on Harold and they become close friends. Harold agrees to trial a possible cure for the disease at a private institute, and the initial results are excellent. But the following day he’s in an even worse state than before, and after Penny accidentally overhears the doctor’s dire prognosis for Harold she decides to sneak him away the next morning. Word soon gets out, and before long a small group of bloodthirsty thugs are pursuing Harold and Penny across dramatic moorlands in the hope of a kill.

Source: TMDb