A Comparison of Arm and Leg Exercise Testing to Predict Cardiovascular Responses to Simulated Work Tasks in Stable Cardiac Patients

Abstract

Nine older men with previously documented myocardial infarction (MI) (age = 63, Max METs = 8.3), were evaluated to determine cardiovascular responses to simulated work tasks. Heart rate (HR), oxygen uptake (VO2), systolic (SP) and diastolic (DP) pressures were first measured during symptom limited arm (AXT) and treadmill (TXT) exercise tests. Subjects subsequently performed three graded work task simulations—weight carrying (WC), repetitive lifting (RL), and overhead work (OW)—which required combined static-dynamic exercise commonly encountered in work activities. VO2, HR, SP, and DP were measured during each work task. Regression lines and confidence intervals for HR, SP, and DP vs percent VO2 max were constructed for AXT and TXT. For each work task, at equivalent percent VO2 max, the frequency of HR, SP, and DP values that fell within ± 1 SD of the TXT and AXT regression lines were compared by chi-square analysis. AXT was a significantly better (P < 0.02) predictor of SP during WC and OW and for DP during each simulated work task. In addition, the HR and VO2 attained during WC and RL were close to maximum VO2 and HR achieved during AXT. AXT provides a more accurate prediction of BP responses and percent VO2 max and percent HR max required for simulated work tasks involving upper body muscle groups.