Vol 12, Issue 2

Heart Rate Acquisition and Threshold-Based Training Increases Oxygen Uptake at Metabolic Threshold in Triathletes: A Pilot Study

February 15, 2019 - By 

Authors

Eric V. Neufeld, David Geffen School of Medicine at University of California, Los Angeles
Jeremy Wadowski, David Geffen School of Medicine at University of California, Los Angeles
David M. Boland, David Geffen School of Medicine at University of California, Los Angeles
Brett A. Dolezal, David Geffen School of Medicine at University of California, Los Angeles
Christopher B. Cooper, David Geffen School of Medicine at University of California, Los Angeles
International Journal of Exercise Science 12(2): 144-154, 2019. 
DOI: 10.70252/HNHZ4958

Abstract

Exercise intensity is a critical component of the exercise prescription model. However, current research employing various non-specific exercise intensity protocols have reported wide variability in maximum oxygen uptake (VO2max) improvement after training, suggesting a present lack of consensus regarding optimal heart rate (fC) training zones for maximal athletic performance. This study examined the relationship between percentage of time (%time) spent training between the metabolic (VO2θ) and ventilatory thresholds (VEθ), and the resultant change in markers of aerobic performance. Thirteen (6 males) collegiate club-level triathletes were recruited for eight weeks of remote fC monitoring during all running and cycling sessions. Participants donned a forearm-worn optical fC sensor paired to a smartphone that collected and stored fCs. Subjects were categorized into Low and High groups based on %time spent training between the VO2θ and VEθ. Significant increases were observed in relative VO2max (P = 0.007, g = 0.48), VO2θ (P = 0.018, g = 0.35), and VEθ (P = 0.030, g = 0.29) from baseline after eight weeks for both groups. A 95% bootstrapped confidence interval that did not include zero (-0.38, -0.03; g = 1.26) revealed a large and significantly greater change in VO2θ in the High group (0.37 ± 0.15 L/min) versus the Low group (0.17 ± 0.14 L/min). No significant differences were observed in other variables between groups. Increasing triathletes’ %time spent exercising between VO2θ and VEθ may optimize increases in VO2θ after eight weeks of training.

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