At the Third Pan-American Congress of Sport Physicians in Chicago in 1959 w
e reported the physiological and clinical significance of the spiroergometr
ic determination of the aerobic-anaerobic turnover point for judging the pe
rformance of sick and healthy persons for the first time.
In this context a distinction was made between a ventilatory and a lactate-
related (arterial blood) method of determination. We called the former meth
od the 'point of optimal ventilatory efficiency (PoW)', and the latter one
'endurance performance limit'. In the 1950s the clinical spiroergometric ex
amination of patients and athletes for the determination of the aerobic per
formance capacity was consistently based on the measurement of the maximal
oxygen uptake. As entering the individual border area of the performance ca
pacity of a patient with, for example, cardiopulmonary disease, can provoke
accidents, we started to think about a criterion in connection with submax
imal work in 1954. Determination of pyruvate and lactic acid in the venous
blood did not prove to be a valid parameter. If the spiroergometric values
were entered into a coordinate system the most striking similarities during
increasing exercise would become evident between the curve of the minute v
entilation and the curve of the arterial lactate. The findings were interpr
eted as follows: during lower grades of performance the oxygen demand in th
e working muscle cells was saturated, whereas in the case of increasing exe
rcise intensity an additional anaerobic metabolism was necessary. We termed
the maximal work load which was covered nearly completely aerobically as t
he PoW and designated heart frequency at this point as 'pulse endurance lim
it'. The determination of the parameter was derived in the coordinate syste
m with a tangent to the curve of the minute ventilation as well as to the c
urve of the arterial lactate. The results of patients and athletes were fir
st published in 1959.