Cardiac repolarisation indices are associated with oxygen consumption during maximal exercise test in highly-trained cross-country skiers

ABSTRACT

The objective of this study was to test the vectorelectrocardiographic T-wave characteristics for their associations with oxygen consumption (VO₂) and physical performance during a maximal cardiopulmonary exercise test (CPET) in highly trained cross-country skiers. Male highly trained cross-country skiers (n = 30) performed the maximal CPET on the bicycle ergospirometric “Oxycon Pro” system with simultaneous oxygen consumption (VO₂) and electrocardiogram recording. The measurements were done at rest; the stage preceding anaerobic threshold (preAnT); peak load; and recovery. The anaerobic threshold was estimated by respiratory exchange ratio. Physical performance was estimated by maximal oxygen consumption (VO_2max/kg). VECG characteristics were calculated using Kors transformation procedure. During the test, the magnitudes of T-vector, Tx and Ty components decreased until preAnT, then stayed relatively stable until peak load, and reversed during recovery. In univariate linear regression analysis, T-vector amplitude and Tx, Ty and Tz magnitudes were associated with VO₂/kg during the test (p < 0.010). The baseline T-vector characteristics were not associated with physical performance. At the preAnT stage, Tx and T-vector amplitude were associated with VO_2max/kg (RC 12.70, 95% CI 0.68–24.73, p = 0.039 and RC 10.64, 95% CI 1.62–19.67, p = 0.023, respectively).

KEYWORDS:

• Athlete
• maximal exercise test
• electrocardiogram
• T-wave
• oxygen consumption
• performance

Disclosure statement

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

Additional information

Funding

This study was performed in the framework of the Program for Fundamental Research of the Russian Academy of Sciences (2022–2026) [projects # 1021052404529-3 and # 1021051201877-3].