1. Savage, Patrick D. MS

Article Content


The measurement of peak aerobic exercise capacity is an important prognostic factor in patients with coronary heart disease and is central to developing an exercise prescription.



While normative values for peak VO2 in healthy individuals are well known, similar measures are not available for patients with coronary heart disease. The objective of this study is to report aerobic exercise capacity in a diverse population entering into cardiac rehabilitation (CR).



Between 1996 and 2004, peak VO2 was measured in 2896 patients entering into CR in Burlington, VT (1502) and Detroit, MI (1394). Peak VO2, was assessed continuously during a symptom limited graded treadmill exercise tolerance test. Cardiopulmonary measures were averaged every 20 seconds and the highest value was termed peak VO2, expressed in relative (mL* kg-1 * min-1) and absolute (L*min-1) terms.



Overall, age of subjects was similar between centers (61 +/- 11 years, range = 21 to 100 years). The Detroit center had more women (33.3 % vs 23.4 %, P <.0001) and more minorities (59 % vs 1 %, P <.0001) than Vermont. Mean peak VO2 for the entire cohort was 17.9 +/- 6.0 mL* kg-1 * min-1 and mean peak respiratory quotient was 1.09 +/- 0.12. Relative and absolute peak VO2 were significantly lower in women compared to men (14.4 +/- 3.9 mL* kg-1 * min-1 vs 19.3 +/- 6.1 mL* kg-1 * min-1 and 1.13 +/- 0.36 and 1.74 +/- 0.61 L*min-1, respectively) (P <.0001), even when adjusted for age. Women were slightly older than men (62 +/- 11 vs 60 +/- 11 years, respectively, P <.0001). Patients undergoing coronary bypass surgery had a significantly lower peak VO2 than non-surgical patients (post-myocardial infaction, percutaneous revascularization and chronic angina) for both females (13.6 +/- 3.4 vs 14.8 +/- 4.1 mL*kg-1 * min-1, P <.0001) and males (17.9 +/- 4.8 vs 20.3 +/- 6.7 mL* kg-1 * min-1, P <.0001).



These results demonstrate that peak VO2 at entry into CR is remarkably low, particularly in women and post surgical patients. Given the negative prognostic implications of a low peak VO2, these results reinforce the importance of CR exercise training.