2024/05/01 by Marie Heiber, A. Schittenhelm, Jennifer Schlie +3 · 1 voice
Medicine · #Cardiovascular and exercise physiology #Sports Performance and Training #Heart Rate Variability and Autonomic Control
paper · pdf · doi:10.2147/oajsm.s444568
openalex publication_date 2024/05/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
Purpose: Lactate threshold (LT) is a critical performance measure traditionally obtained using costly laboratory-based tests. Wearables offer a practical and noninvasive alternative for LT assessment in recreational and professional athletes. However, the comparability of these estimates with the regular field tests requires further evaluation. Patients and Methods: In our sample of 26 participants (n f =7 and n m =19), we compared the estimated running pace and heart rate (HR) at LT with two subsequent tests. First, participants performed the Fenix 7 ® threshold running test after a calibration phase. Subsequently, they were tested in a standardized, graded blood lactate field test. Age was 25.97 (± 6.26) years, and body mass index (BMI) was 24.58 (± 2.8) kg/m 2 . Results: Pace at LT calculated by Fenix 7 ® ( M =11.87 km/h ± 1.26 km/h) was 11.96% lower compared to the field test ( M =13.28 km/h ± 1.72 km/h), which was significant ( p < 0.001, d =− 1.19). HR estimated by the Fenix 7 ® at LT was 1.71% lower (p > 0.05). LT data obtained in the field test showed greater overall variance. Conclusion: Our results suggest sufficient accuracy of Fenix 7 ® LT estimates for recreational athletes. It can be assumed that for professional athletes, it would fail to provide the nuanced data needed for high-quality training management. Keywords: smartwatch, physical performance, physiology, heart rate, pace