Setting a cap or target for recovery runs and rest day runs as described above and then sticking to it will help to assure that the racehorses will recover properly. Train with a slower partner on recovery runs or rest day runs. The rationale is the same as for using a heart rate monitor, but this method is more social and more frugal, albeit less precise and a bit more logistic-dependent. Take the watch off on recovery days. Pace should not even be on the radar as an objective for these types of runs.
Recovery is more than a type of running.
Recovery can also be facilitated by attention to non-running elements of a total training program. Attention to optimizing sleep, hydration and diet can help enhance recovery and prevent injury, illness, and overtraining syndrome. Massage may also be of benefit in facilitating recovery. When in doubt, leave it out. Instead, substitute a recovery run, or better yet, a rest unit for the stressor unit.