Could a Short Incremental Test Be a Valid Cardiorespiratory Efficiency Assessment Tool in Obese Adults? A Comparison between Two Exercise Testing Protocols.

Background: To assess cardiorespiratory efficiency in obese adults, two exercise test treadmill protocols with 2- or 3-minute stages were compared.

Methods: Thirty-six obese adult subjects were involved in this study. Sixteen men (age 51.5±10.5 years; body mass index [BMI] 36.7±4.8 kg/m) and 20 women (age 42.4±12.4 years; BMI 36.5±4.7 kg/m) performed submaximal incremental graded tests on treadmills with 2- or 3-minute stages on different days. During each testing session, heart rate (HR), oxygen uptake (VO mL/min/kg), rate of perceived exertion (RPE), fat oxidation (FO) at maximal fat oxidation (MFO), and maximal fat oxidation zone (Fatmax zone) were measured.

Results: No differences were found for HR, VO, and RPE at MFO between the two protocols. Significant differences (2-minute vs. 3-minute) were found for FO (576.3±162.9 mg/min vs. 506.0±148.1 mg/min respectively; <0.05) at MFO between the two protocols. No differences were found for VO and HR in high and low Fat zone borders. Moreover, a difference was found for FO at the low and high borders.

Conclusion: Exercise intensity at which the MFO and Fat zone occur is not influenced by the duration of stage-to-stage increments. The two exercise testing protocols could be considered interchangeable to assess HR, VO, and RPE at MFO.