Physiologic Responses of Patients With Cardiac Disease to Arm, Leg, and Combined Arm and Leg Work on an Air-Braked Ergometer

Abstract

Cardiorespiratory responses to three modes of air-braked ergometry were compared in nine stable patients with cardiac disease ( ± standard deviation [SD]: age, 63.7 ± 6.2 years of age; height, 172.2 ± 4.0 cm; weight, 75.8 ± 14.4 kg). Exercise modes included arm ergometry (AE), leg ergometry (LE), and combined arm and leg ergometry (ALE). A discontinuous protocol was selected with 3 minutes of exercise and 1 minute of recovery. Work loads were increased 0.5 kiloponds (kp) per stage. Tests were conducted to volitional fatigue. A two-way repeated analysis of variance (ANOVA) was used to determine significance between the exercise modes. Actual vs American College of Sports Medicine (ACSM) predicted oxygen uptake (VO2) values were evaluated by ANOVA to determine accuracy of predicted values. Heart rate (P < 0.05), minute ventilation (VE) (P < 0.001) ventiatory equivalents for oxygen (O2) (P < 0.001) and carbon dioxide (CO2) (P <0.05), and calculated myocardial oxygen uptake (MVO2) were significantly higher (P < 0.05) for AE than either LE or ALE at work loads of 1.0, 1.5, and 2.0 kp. Oxygen uptake (P < 0.05) and CO2 production (VCO2) (P < 0.01) were significantly elevated during AE, and this reflected a significantly elevated respiratory exchange ratio (RER) (P < 0.001). Mechanical efficiency (ME) was lower during AE compared with LE or ALE. Average maximal work loads for AE were 57% lower than for either LE or ALE. This was associated with a 14% lower value for VE, 18% lower value for VO2, 25% lower value for calculated metabolic equivalents (METS), and a 27% lower value for ME. For all exercise modes, actual VO2 values were compared with the ACSM predicted VO2 values The ACSM equation for AE significantly overpredicted VO2 at 1.5 to 2.5 kp work loads. The LE equation tended to underpredict at low work loads (0.5 and 1.0 kp) and overpredicted VO2 at the higher work loads (2.5 kp and greater). The results of this study suggested that in this population of patients with cardiac disease, AE is conducted at a higher cardiorespiratory cost than LE or ALE. The use of ACSM prediction equations warrants additional study regarding this type of lever-action upper-body exercise.