Abstract

Gas exchange, blood lactate and blood gas were studied during an incremental exercise test on a bicycle ergometer on ten healthy male subjects. Gas exchange was measured breath-by-breath. A teflon catheter was inserted percutaneously into a brachial artery for sampling of arterial blood. Blood lactate was measured by enzymatic technique. The blood gas parameters (PO2, PCO2, pH, HCO3-) were analyzed by the Radiometer (Copenhagen). Because of the widespread use of the determination of the anaerobic threshold (AT), we felt it would be important to compare the values of oxygen uptake and work rate discerned from four criteria: 1. gas exchange break point (ventilatory threshold VT); 2. lactate break point (lactate threshold LT); 3. 2 mM (lactate); and 4. 4 mM (lactate). The data have shown that there is no significant difference in oxygen uptake and work rate (P>0.05) whether measured by gas exchange or blood lactate in nine subjects. Compared to the gas exchange criteria, work rate measured by the other three methods was higher by 1.5, 55.5 and 109.5 watts respectively; the last two being significantly different (P<0.05). The blood gas parameters, which are used for detection of the AT, have a great individual variation. Thus, the methodological aspects in the determination of the AT need to be further studied and standardized. Verf.-Referat