What is the test for a failure to mitigate?

In Chiu v. Chiu, 2002 BCCA 618, Low J.A. explained the test to be applied in determining whether a defendant has proven a failure to mitigate. At paragraph 57 he wrote: … In a personal injury case in which the plaintiff has not pursued a course of medical treatment recommended to him by doctors, the defendant must prove two things: (1) that the plaintiff acted unreasonably in eschewing the recommended treatment, and (2) the extent, if any, to which the plaintiff’s damages would have been reduced had he acted reasonably. …

The defendant argues that the plaintiff has failed to mitigate her damages in several ways. The principal basis is the plaintiff’s failure to follow the exercise and stretching regime that several health care professionals have recommended. A similar failure was alleged in Antoniali v. Massey, 2008 BCSC 1085. At paragraph 31 Preston J. set out that which the defendant must prove in order to establish a failure to mitigate on that basis: 1. that a program of stretching and conditioning under the guidance of a personal trainer would have reduced or eliminated the effect of the injuries; 2. that the reasonable plaintiff in [the plaintiff’s] circumstances would have followed such a program; 3. that [the plaintiff] unreasonably failed to follow such a program and; 4. the extent to which [the plaintiff’s] damages would have been reduced if she had followed such a program.