Association Among Different Aerobic Threshold Markers and FATmax in Men With Obesity

ABSTRACT

Purpose: This work studies the interrelation of the first ventilatory threshold (VT1), the heart rate inflection point (HRIP), and the exercise intensity at which blood lactate started to accumulate (LIAB) or increased 1 mmol∙L-1 above baseline (LT+1.0); and examinee their association with the exercise intensity eliciting maximal fat oxidation (FATmax). Methods: Eighteen young men with obesity performed an incremental-load exercise test on a treadmill after overnight fasting. Gas exchange, heart rate, and blood lactate concentration were recorded. Linear regression analysis was used to determine the association among FATmax and AeT markers. A standard error of estimate (SEE) ≤9 beats∙min-1 and the concordance correlation coefficient (CCC) were used to examine the accuracy of different AeT for predicting FATmax heart rate. Results: The FATmax occurred at 36±7%VO2peak before the HRIP (41±6%VO2peak), LIAB (42±10%VO2peak), LT+1.0 (61±9%VO2peak) and VT1 (40±7%VO2peak). Furthermore, the HRIP (R2= 0.71; SEE= 6 beats∙min-1; CCC=0.77), VT1 (R2= 0.76; SEE= 5 beats∙min-1; CCC=0.84) and LIAB (R2= 0.77; SEE= 5 beats∙min-1; CCC=0.85) were strongly associated to FATmax and showed an acceptable estimation error for predicting FATmax heart rate. Otherwise, LT+1.0 showed a moderate correlation with FATmax, a low accuracy for predicting FATmax HR (R2= 0.57; SEE= 7 beats∙min-1; CCC=0.66) and a poor agreement with the rest of AeT markers (Bias: +20%VO2peak). Conclusion: The HRIP, LIAB and VT1 did not perfectly captured the FATmax, however, these could be exchanged for predicting the FATmax heart rate in men with obesity. Moreover, the LT+1.0 should not be used for AeT or FATmax assessment in men with obesity.                                  

KEYWORDS:

• Anti-obesity agents
• energy metabolism
• exercise test
• indirect calorimetry

Acknowledgments

The authors thank all the subjects who kindly participated in the study. Likewise, the authors recognize Alejandra Zavala and Martin Perez, who designed the control dinner meals. IACG was supported by a PhD scholarship (859438) from the Consejo Nacional de Ciencia y Tecnología (CONACyT). However, the institution did not participate in the study design or manuscript preparation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authorship

Investigation and visualization, IACG; conceptualization and methodology, RPHT; resources and data curation, MTT; formal analysis, VMB, EGR; supervision and project administration, ARJ. All authors have read, edited, and approved the final version of the manuscript, and agree with the order of presentation of the authors.

Data sharing

The dataset supporting the results from this study is available from the corresponding author upon request.

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.