Determination Of IANT Via Heart Rate Variability In Overweight And Obese Subjects

Abstract

Numerous studies reported that the heart rate variability (HRV) may be used to determine the aerobic-anaerobic thresholds (IANT) in healthy trained participants (Flöter et al. 2012; Karapetian et aI. 2008). PURPOSE: The aim of this study was to assess if the IANT may also be determined in overweight and obese subjects utilizing the non-linear response of HRV. METHODS: 28 overweight and obese participants (age: 38.5 + 13.1 yrs; Wt: 96.4 + 16.7 kg; BMI: 30.9 + 4.4 kg-1.m2; %body fat: 29.2 + 4.3; waist circumference: 107.8 + 10.9 cm) completed a two stage incremental test on cycle ergometer (Braumann et al. 1993) followed by continuous performance test to determine and validate the lactate thresholds and IANT as described by Heck et al. 1985. The examination of individual HRV variables and associated HRV thresholds were determined via continuous 12-lead ECG monitoring and recordings (Flöter et al. 2012). The agreement of resulting power output thresholds expressed in Watts (W) in the region of IANT and those determined from HRV recordings were ascertained via Bland-Altman plots and correlation analysis. RESULTS: The calculated thresholds generated from HRV recordings were above those performed in IANT (W: 126 + 30.7; utilizing the Pointcare Chart variability, SD1 of 144.8 + 32.9 = standard deviation of the short-term RR interval variability of transverse axis; SD2 of 146.1 + 30.5 = standard deviation of the long-term RR interval variability of longitudinal axis; SD1/SD2 ratio of 145.2 + 27.8; SD1/HR ratio of 144.4 + 32.2). The results revealed agreements in IANT determination that were confirmed via Bland-Altman Plots as well as significant correlation coefficients generated from the cycle ergometer power output (SD1 = 0.69; SD2 = 0.61; SD1/SD2 = 0.66; SD1/HR = 0.68). CONCLUSION: The results of this study yielded moderate to strong associations between HRV threshold data and results determined via IANT power output on cycle ergometer. In our overweight and obese participants, the response in HRV variability was present and possible only during the short-term analysis.