Submaximal fitness and mortality risk reduction in coronary heart disease: A retrospective cohort study of community-based exercise rehabilitation

Objectives To examine the association between submaximal cardiorespiratory fitness (sCRF) and all-cause mortality in a cardiac rehabilitation (CR) cohort. Design Retrospective cohort study of participants entering CR between 26 May 1993 and 16 October 2006, followed up to 1 November 2013 (median 14 years, range 1.2–19.4 years). Setting A community-based CR exercise programme in Leeds, West Yorkshire, UK. Participants A cohort of 534 men (76%) and 136 women with a clinical diagnosis of coronary heart disease (CHD), aged 22–82 years, attending CR were evaluated for the association between baseline sCRF and all-cause mortality. 416 participants with an exercise test following CR (median 14 weeks) were examined for changes in sCRF and all-cause mortality. Main outcome measures All-cause mortality and change in sCRF expressed in estimated metabolic equivalents (METs). Results Baseline sCRF was a strong predictor of all-cause mortality; compared to the lowest sCRF group (<5 METs for women and