Observer ratings of perceived exertion in relation to self ratings and heart rate

The results from a comparison made between observers' estimations of a bicycling subject's exertion and the self-raters' perceived exertion show that one can draw conclusions of an individual's exertion at physical work by using observer ratings. Six bicycling subjects (self-raters) cycled on a bicycle ergometer at six different power levels presented in random order. The estimations were made simultaneously by the observers and the self-rater during the last half minute at each power level. At the same time the self-rater's heart rate was registered. In accordance with earlier findings on physical work, the relation between heart rate and power level was linear. The estimations were made on a category-ratio scale as well as with magnitude estimation. The observers found the category-ratio scale easier to use and it seems as if the category-ratio scale is as reliable as magnitude estimation for these kinds of ratings.