Individualized exercise prescription: how can the submaximal test help us?

INTRODUCTION: Exercise intensity is the most critical component of the exercise prescription process. Different methods to determine exercise intensity, deriving from maximal or submaximal protocols have been critically compared1. No studies have related an approach based on ventilatory thresholds (VT) with the corresponding intensity relative to reserve anchors. Therefore, the aim of this study was to understand how the exercise intensity at VT derived from a test to exhaustion (CPET) be equated to a workload derived from a submaximal test (SUB). METHODS: Subjects included twenty-four healthy adults (14 M, 10 F; age: 23.2±2.8 yrs; BMI: 22.1±3.0 kg·m-2; RMR: 3.4±0.5 mL·kg-1·min-1). Oxygen uptake (V̇O2), heart rate (HR) and rate of perceived exertion (RPE, CR-10) were measured at rest and during SUB and CPET, both performed using a cycle ergometer and a metabolic cart. V̇O2max was obtained: 1) at the end of the CPET ramp protocol (V̇O2maxCPET), and the V̇O2 at first and second VT (V̇O2@VT1 and V̇O2@VT2) was calculated, 2) by submaximal test (V̇O2maxSUB), based on YMCA protocol, and extrapolated to predicted maximum HR (HRP, 208−0.7·age). V̇O2 reserve (V̇O2R) was calculated considering resting V̇O2, and %V̇O2R corresponding to V̇O2@VT1 and V̇O2@VT2 was extrapolated. RESULTS: No significant differences were found between estimated or measured variables (V̇O2maxSUB 43.7±9.3, V̇O2maxCPET 44.7±8.7 mL·kg-1·min-1), p=.444; HRP 191.8±2.0, HRmaxCPET 187.8±10.2 bpm, p=.065), except, as expected, for the RPE recorded at the end of each test (RPESUB 4.9±2.1, RPECPET 9.2±1.6, p<.001). The V̇O2@VT1 (26.4±4.9 mL·kg-1·min-1) and V̇O2@VT2 (36.1±7.8 mL·kg-1·min-1) corresponded to 54.4±13.9% and 82.4±13.7% of V̇O2R, respectively. CONCLUSION: To our knowledge, this is the first study which attempt to compare VT intensity from CPET to the corresponding percentage of V̇O2R based on submaximal test. Exercise intensity at VT1 and VT2 can be considered as moderate and vigorous, respectively, compared to the physical activity guidelines2. This approach is important to enhance trainers and physicians’ ability to understand and customize an effective exercise prescription in a non-clinical setting. 1 Jamnick. Sports Med. 2020 Oct;50(10):1729-1756. 2 ACSMs Guidelines for Exercise Testing and Prescription,11thed. LWW, 2021.