Int J Sports Med
DOI: 10.1055/a-2721-9979
Training & Testing

Estimation of Runnersʼ Lactate Threshold Heart Rate and Speed by Heart Rate Variability

Authors

  • Changda Lu

    1   School of Sport Science, Beijing Sport University, Beijing, China (Ringgold ID: RIN47838)
  • Siyu Lu

    2   School of Sports Engineering, Beijing Sport University, Beijing, China (Ringgold ID: RIN47838)
  • Yiwei Wu

    1   School of Sport Science, Beijing Sport University, Beijing, China (Ringgold ID: RIN47838)
  • Qingjun Xing

    1   School of Sport Science, Beijing Sport University, Beijing, China (Ringgold ID: RIN47838)
  • Bingyu Pan

    2   School of Sports Engineering, Beijing Sport University, Beijing, China (Ringgold ID: RIN47838)
    3   China Sports Big Data Center, Beijing Sport University, Beijing, China (Ringgold ID: RIN47838)
  • Yanfei Shen

    2   School of Sports Engineering, Beijing Sport University, Beijing, China (Ringgold ID: RIN47838)
    4   Engineering Research Center of Strength and Conditioning Training Key Core Technology Integrated System and Equipment, Ministry of Education of the Peopleʼs Republic of China, Beijing, China (Ringgold ID: RIN12543)

Supported by: This study was supported by the Fundamental Research Funds for the Central Universities of China 2023GCZX003 and The National Natural Science Foundation of China72071018

Abstract

Accurate measurement of training intensity is crucial for optimizing endurance running performance. Lactate threshold heart rate and lactate threshold speed are commonly used but require invasive, costly methods. Heart rate variability metrics offer a non-invasive alternative by assessing autonomic nervous system activity. This study evaluated the validity of various heart rate variability metrics in predicting the lactate threshold heart rate and lactate threshold speed during indoor and outdoor graded exercise tests in 19 recreational runners. Heart rate variability thresholds were determined using SD1, SD2, detrended fluctuation analysis scaling exponent for short-term fluctuations, detrended fluctuation analysis scaling exponent for long-term fluctuations, standard deviation of NN intervals, and root mean square of successive RR intervals via the Dmax method, and are referred to as HRVT1 to HRVT6. Indoor graded exercise test results showed that heart rate at heart rate variability threshold often underestimated the lactate threshold heart rate, with all heart rate variability thresholds, except speed at heart rate variability threshold (detrended fluctuation analysis scaling exponent for long-term fluctuations, p=0.06), showing significant differences from lactate threshold. Moderate correlations were observed for HRVT5HR (standard deviation of NN intervals, r=0.66), HRVT2speed (SD2, r=0.56), and HRVT3speed (detrended fluctuation analysis scaling exponent for short-term fluctuations, r=0.70). Outdoor graded exercise tests showed no significant differences between most heart rate variability thresholds and lactate threshold, except HRVT6HR (root mean square of successive RR intervals, p=0.03). Speed at heart rate variability threshold demonstrated moderate correlations (r=0.54–0.7) with the lactate threshold speed. While the heart rate variability threshold and lactate threshold may reflect different physiological thresholds, heart rate variability thresholds, particularly those based on detrended fluctuation analysis scaling exponent for long-term fluctuations, showed promise as non-invasive predictors of lactate threshold in recreational runners.



Publication History

Received: 03 May 2025

Accepted after revision: 13 October 2025

Accepted Manuscript online:
13 October 2025

Article published online:
21 November 2025

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