Effects of order of presentation of exercise intensities and of sauna baths on perceived exertion during treadmill running

Thirteen male subjects performed a running test on the treadmill consisting of four standard exercise intensities [65%, 75%, 85%, 95% maximal O2 uptake (VO2max)] presented in ascending, descending or random order. At the end of each exercise intensity, O2 consumption, heart rate (fc), venous blood lactate concentration ([la]b) and perceived exertion were assessed. This last variable was determined according to the Borg nonlinear CR-20 scale. The same variables were also determined during exercise at a standard intensity (65% or 95%VO2max) performed before and after a Finnish sauna bath. Ratings of perceived exertion showed a good test-retest reliability (r=0.77); they were the same when the exercise intensity was expressed in relative (%VO2max) or absolute (speed) terms, and were independent of the order of presentation of the exercise. The latter had no effect on fc either but it did, however, influence [la]b, which was significantly higher in the descending, as compared to the ascending or random modes of presentation. The sauna bath increased fc at a given exercise intensity, but left perceived exertion and [la]b unchanged. It was concluded that at least under the present experimental conditions, fc and venous [la]b do not play a major role as determinants of perceived exertion. © 1991 Springer-Verlag.