Abstract
We sought to investigate the effects of wearing a mobile respiratory gas analysis
system during a treadmill test on blood lactate (bLa) concentrations and commonly
applied bLa thresholds. A total of 16 recreational athletes (31±3 years, V̇O2max: 58±6 ml · min−1 · kg−1) performed one multistage treadmill test with and one without gas exchange measurements
(GEM and noGEM). The whole bLa curve, the lactate threshold (LT), the individual anaerobic
thresholds according to Stegmann (IATSt) and Dickhuth (IATDi), and a fixed bLa concentration of 4 mmol ∙ l−1 (OBLA) were evaluated. The bLa curve was shifted slightly leftward in GEM compared
to noGEM (P<0.05), whereas the heart rate response was not different between conditions (P=0.89). There was no difference between GEM and noGEM for LT (2.61±0.34 vs. 2.64±0.39 m · s−1, P=0.49) and IATSt (3.47±0.42 vs. 3.55±0.47 m · s−1, P=0.12). However, IATDi (3.57±0.39 vs. 3.66±0.44 m · s−1, P<0.01) and OBLA (3.85±0.46 vs. 3.96±0.47 m · s−1, P<0.01) occurred at slower running velocities in GEM. The bLa response to treadmill
tests is mildly affected by wearing a mobile gas analysis system. This also applies
to bLa thresholds located at higher exercise intensities. While the magnitude of the
effects is of little importance for recreational athletes, it might be relevant for
elite athletes and scientific studies.
Key words
cardiopulmonary exercise testing - performance diagnostics - lactate threshold - V̇O
2max
- metabolic device
