The influence of 10 min warming-up at 40% VO2 max on thermal, circulatory, and 
metabolic responses to an incremental exercise to exhaustion as well as on the 
anaerobic threshold at the blood lactate level of 4 mmol.l-1 (AT) and the 
individual anaerobic threshold (IAT) was investigated in eight cross-country 
skiers. During exercise preceded by warming-up, the mean skin temperature (T sk) 
and external auditory canal temperature (Tac) did not change significantly in 
contrast to exercise without warming-up, producing a rise in both T sk and Tac 
(by approx. 1.2 degrees C and 1.1 degrees C, respectively). Warming-up did not 
alter the course of the rectal temperature changes during exercise. With 
warming-up skin humidity rose immediately after the beginning of exercise, 
whereas the onset of sweating without warming-up appeared much later at higher 
work intensities. Warming-up did not change the circulatory and ventilatory 
responses to incremental exercise and the oxygen uptake (VO2) either at 
submaximal or maximal work loads. With warming-up a significant increase was 
found in the threshold work load both at the AT and the IAT. The data 
demonstrated that warming-up has an advantageous effect on the efficiency of 
thermoregulation in endurance-trained athletes producing an early sweating 
response to the incremental exercise that results in attenuation of 
hyperthermia. An increase in the anaerobic threshold during incremental exercise 
preceded by warming-up may indicate an enhancement of the endurance capacity 
subsequent to warming-up.