Does Heart Rate Response Confirm The Attainment Of Maximal Oxygen Uptake In Adults 45 Years And Older?

Abstract

Heart rate plateau (HRplat) is an effective indicator for confirming V˙O2max attainment. However, it is unknown if this criterion holds for older populations. PURPOSE: Test the efficacy of HRplat for confirming V˙O2max in older individuals. METHODS: Twelve males and twelve females (60±8 years, N=24) completed individualized ramp and staged protocols to volitional fatigue on the cycle ergometer (CE) and treadmill (TM), respectively. Participants then performed verification protocols at 105% of their peak workload from each V˙O2max test. V˙O2max was confirmed using a plateau in V˙O2 (V˙O2plat = largest V˙O2 value – closest neighboring point ≤150 ml/min), a V˙O2max verification criterion of a V˙O2 not greater than 2% higher than the incremental phase, and two different criteria for HRplat (≤2 bpm or ≤4 bpm). Secondary criteria for establishing maximal effort were RERmax ≥1.10, HRmax ±10 bpm of APHRmax, RPE ≥17, and [BLa-] ≥ 8mM. RESULTS: Data are presented (Table 1) as sex-specific percentages. All attained V˙O2plat on both modalities. The verification criterion was met by ≥ 67% of females and ≥ 92% of males in our sample regardless of modality. HRplat (≤2 bpm) was met by ≤ 67% of females and ≤ 44% of males in our sample regardless of modality. Males more frequently attained HRplat (≤4 bpm) than did females; females attained HRplat (≤4 bpm) more frequently on TM as compared to CE. CONCLUSION: A verification bout is reliable for confirming V˙O2max in older males on both modalities and for females on the TM. HRplat (≤4 bpm) may serve as a standalone criterion for TM V˙O2max attainment for males and females. V˙O2plat was the most robust method for confirming V˙O2max attainment in older adults. Due to wide variability in the literature regarding V˙O2plat criteria and indirect calorimetry processing methods, agreement on a standardized definition for V˙O2plat and clear data processing procedures are needed.Table 1: V˙O2max attainment criteria for all tests across sex and modality (N=24)