Adequate exercise is a fundamental horse welfare need; insufficient exercise causes physical deterioration, stereotypic behaviour, and psychological problems in stabled horses.
Exercise deprivation in horses causes welfare harm through both physical and psychological mechanisms. Physically, stabled horses that do not receive adequate exercise develop cardiovascular deconditioning, muscle atrophy, and poor bone mineralisation. Psychologically, the absence of movement that horses are evolved for creates frustration that commonly manifests as stereotypic behaviour. Competition horses kept in intensive stable management for performance preparation face an inherent tension between the exercise restriction that some training programmes impose and the horse's welfare need for movement. Management approaches that provide turnout and exercise as non-negotiable welfare minimums rather than optional extras achieve better welfare outcomes.