Assessment of Aerobic Capacity A Novel Rating Scale and Further Development of an Exercise Test including Analysis of Gas Exchange

Abstract: Different methods are proposed to assess the aerobic capacity. A novel scale, rating of perceived capacity (RPC) based on metabolic equivalents (METs) from 1 to 20, is presented. Selected MET values are linked to physical activities. Comparison of the rating with an exercise test in a group of women revealed that a correction based on age more accurately predicted the maximal exercise capacity. An incremental exercise test, including a constant work rate for four minutes, was introduced and combined with breath-by-breath measurements of gas exchange. Data collected every ten seconds were digitally filtered to determine selected variables. Fits of polynomials were utilised to determine the increasing contribution of the anaerobic metabolism, reflected by V'CO2, at three different thresholds. Equations were utilised to assess the time constant of V'O2 (Tau V'O2) (reflecting the time required to reach steady state) and the change in V'O2 corresponding to a specific change in work rate (delta V'O2/delta W). The repeatability of measures of the aerobic capacity (V'O2max, the three thresholds, V' O2 and delta V' O2/delta W) and of variables at rest, at sub-maximal and maximal levels was investigated. Considerable variations were found, which could mainly be explained by biological variation. Reference values for aerobic capacity were generated based on values from 25 healthy women (22–44 years) at low or moderate activity levels, and 41 healthy men (18–48 years) at moderate capacity. The results show that several variables and parameters can be determined in a single exercise test, which together describe the aerobic profile in a comprehensive manner.