T-Wave Minimum as Indicator of Whole Body Steady State in Incremental Exercise

Busse M1, Fikenzer S1, Poekel C1, Schulze, A1, Thomas, M1, Tegtbur U2, Falz R1

Institute of Sports Medicine, University of Leipzig1 (Director: Prof. M. Busse, MD)
Department of Sport Medicine, Medical School Hanover2 (Director: Prof. Dr. U. Tegtbur,  MD)

Summary

Busse M, Poekel C, Schulze A, Tegtbur U, Thomas M, Falz R. T-wave minimum as indicator of whole body steady state in incremental exercise. Clinical Sports Medicine International (CSMI) 2012, 5: 1-6

Objective:This study examines the correlation between a minimum of T-wave AUC (T-MinAUC)and lactate or ventilatory thresholds.

Materials and methods:32 male students of the University of Leipzig (average values: age – 23.9 yrs, BMI – 23.8 kg/m2) participated in a double incremental maximum test (Test A,B) after written informed consent and as a part of their study curricula. Vector-ECG was recorded each minute. VE was measured breath by breath, lactate values were taken every minute. T-wave area under the curve (T-AUC) was calculated from the 3-dimensional vector recordings (x/y/z). Bland-Altman procedure and linear regression analyses were used to compare the results.

Results:

• Maximum workload (Wmax): 302 ± 29 watt
• T-MinAUC: 192 ± 31 watt (64% Wmax)
• Lactate minimum: 213 ± 28 watt (71% Wmax)
• Ventilatory threshold: 245 ± 30 W (81% Wmax)
• Reproducibility of T-minimumAUC (comparison of Test A and B): Pearson r is 0.73, indicating a good correlation between T-minimumAUC in Test A and B.

Conclusion: The T-minimum of the T-wave AUC is a reproducible exercise variable, though no strong correlation to other indicators of exercise intensity may exist. In this present study the physiological relevance of the T-MinAUC still remains unclear. From former studies it may be hypothesized that T-MinAUC indicates the change from decreasing vagal to increasing sympathetic drive.

Keywords: exercise, T-wave, T-wave minimum, threshold