Usability Of Capillary Or Venous Lactate And Advantages Of Venous PO2 During Performance Test

PURPOSE:In low performance zones ear-lobe lactate (ELL) values can be expected to be inexact, for it is defined from a mixture of arterial and venous blood in a new breathing cycle. The accuracy of the test strip is also limited. As an alternative we chose to apply a self-calibrating system using 0.4 ml venous blood to measure lactate more accurately. METHODS:16 handball players were put to a high intensity training test on treadmill monitoring venous blood gas (VBG) lactate step to step. We searched for correlations between the fluctuation of performance and measured values. Step periods were divided into zones: 4-6-8 km/h (warm-up = W), 10-12 km/h (medium = M), 14-16 km/h (cardio = C), 18-20 km/h (peak = P) RESULTS:Differences in venous and capillary lactate were significant (p < 0,05) during W and P which could be the result of the limitations of test strip and the possible dilution of blood in the earlobe by sweat. A further advantage of VBG was that it provided us with partial pressure of oxygen (pO2) values, which, based on the Bohr effect helped us understand muscle saturation (SMO2) measured by a wearable device. Mean+/-SD W = 35,0+/-11,7, M = 48,6+/-10,6, C = 44,9+/-9,09, P 40,8+/-14,4 mmHg, yet what was even more convincing were minimum/maximum values: W = 22,1 vs. 57,1, M = 31,2 vs 66,0, C = 25,2 vs 54,5, P = 25,1 vs 80,8 mmHg. Only increasing oxygen during M correlated with values during W. During P the group split into two which implies discrepancies of breathing efficiency. Insulin was measured, values were: mean+/-SD W = 8,45+/-5,87, M = 4,65 +/-1,84, C = 7,55 +/- 2,91, P = 8,35+/-4,85 mIU/ml. CONCLUSIONS: Inaccuracy of W ELL which shows best the heart rate zones during endurance training. P ELL has poor relevancy against VBG to select player based on performance and high intensity zone is a marker in explosiveness and concentration. Low or normal pO2 values show if breathing needs improvement. Secondly, the elevation of insulin with low oxygen supply generates acidosis and higher carbohydrate utilisation instead of fat in muscles. The VBG system allows the definition of aerobic-anaerobic zones more precisely than ELL and draws attention to pathological signs. Expenses of an examination USD 30 ELL vs USD 60 VBG, but VBG system involves a larger one-time investment and know-how, but provides wider diagnosis of the elite athletes.