Background: In many countries exercise prescriptions are used in an attempt to initiate a physically active lifestyle in sedentary populations. Previous studies have primarily evaluated low intensive exercise prescription interventions and found moderately positive effects on physical activity and aerobic fitness. In a highly intensive Danish exercise prescription scheme called 'Exercise on Prescription' (EoP) the general practitioners can prescribe EoP to sedentary patients with lifestyle diseases. The aim of this randomized trial is to assess the short-and long-term effects of the EoP scheme. Thus, the aim of this paper is to describe the randomized controlled trial designed for evaluating effectiveness of EoP, and to present results from validations of outcome measures.

Inhalation of CO(2)-enriched air and the ensuing respiratory acidosis increase steady-state VO(2) in both light and heavy exercise and enlarges O(2) deficit in heavy exercise.