The Influence of Fitness Status on Cardiorespiratory Responses to Continuously Graded & Ramped Treadmill Protocols

Abstract

0788 Continuously ramped treadmill protocols (RTP) are often used in low-fit populations for diagnostic and functional stress testing because the relatively small and frequent adjustments in workrate result in lower cardiorespiratory responses at equivalent workrates, greater treadmill time and are better-tolerated as compared to traditional graded treadmill tests (GTP). However, similar responses to RTP in moderate and high fit individuals remain to be shown. PURPOSE: To compare cardiorespiratory responses to RTP and GTP in middle-aged adults of different fitness status. METHODS: 71 apparently healthy men and women (42 ± 8 yr of age) [32 high fit (BMI = 24.2 ± 3.3 kg/m2, VO2 peak > 69th percentile), 13 moderately-fit (BMI = 24.9 ± 2.3 kg/m2, VO2 peak 50–69th percentile) and 26 low-fit (BMI = 27.5 ± 4.7 kg/m2, VO2peak < 50th percentile)] completed a maximal standardized RTP and a GTP that were matched for workrates every 3 min in a randomized cross-over design. Differences in total treadmill time, heart rate (HR), systolic (SBP), diastolic (DBP) and mean arterial blood pressure (MAP), rate pressure product (RPP), oxygen consumption rate (VO2), ventilatory rate (VE), and perceived exertion (RPE) at equivalent workrates were determined using 3 (Group) × 2 (Treadmill Test) ANOVAs. RESULTS: Total treadmill time, VO2 peak and VEpeak were greater in high- and moderate-fit versus the low-fit group. HR, SBP, DBP, MAP, RPP, VO2, VE were lower at submaximal intensities and total treadmill time, but not VO2peak, was greater in RTP compared to GTP across groups (P< 0.05 for all). CONCLUSIONS: Cardiorespiratory responses to increasing physical stress are more modest at equivalent workrates during RTP and result in longer total treadmill times versus GTP; however, RTP and GTP elicit similar peak cardiorespiratory results and are equally tolerated across fitness levels.