Introduction: Diabetes is a major coronary heart disease (CHD) risk factor and is highly prevalent among patients with CHD. Maximal exercise capacity tends to be lower in patients with diabetes than in patients without diabetes. It is unknown whether submaximal exercise capacity as assessed by the 6-minute walk test is similarly reduced.

Purposes: To explore differences in submaximal exercise capacity in CHD patients with and without diabetes. To compare submaximal exercise capacity in both groups to that of age, gender, height, and weight matched healthy individuals.

Methods: Data were extracted from the cardiac rehabilitation database. Demographics, clinical characteristics, and exercise measures were compared between CHD patients with and without diabetes. Percent predicted walk distance was calculated based on published equations adjusting for age, gender, height, and weight. Correlates of percent predicted walk distance were determined by multivariate linear regression modeling.

Results: Patients with diabetes (n = 199) had a greater risk factor and comorbidity burden and more depressive symptoms than patients without diabetes (n = 322). Mean distance walked for diabetic patients was 370 +/- 118 m (71 +/- 21% predicted), for patients without diabetes 412 +/- 109 m (78 +/- 21% predicted). Diabetes was independently associated with percent predicted walk distance after controlling for differences in baseline characteristics between groups.

Conclusions: Patients with CHD and diabetes had lower submaximal exercise capacity than CHD patients without diabetes. Both groups had lower than expected walk distances compared to healthy adults. Exercise interventions need to consider the special needs of patients with diabetes.