The Astrand-Ryhming nomogram revisited.

Relationships among O2 uptake (VO2), heart rate, and work rate during constant-load submaximal cycle ergometry and ramp-forced exercise to exhaustion have been studied in core groups of trained (n = 15) and untrained (n = 10), 20- to 29-yr-old males. A signal aim was to improve on the accuracy of the 1954 Astrand-Ryhming (A-R) nomogram predicting maximum aerobic power from heart rate elevation at submaximum work rates. A new nomogram has been developed based on a linear relationship, established in experimental groups, between VO2 and delta HR, the latter being defined as the elevation of exercise heart rate above that reached during zero-load pedaling at 90 rpm. The delta HR variable used in a nomogram linking it and submaximum VO2 (either derived by calculation from the concomitant steady-state work rate or measured directly from respiratory gas analysis) successfully differentiated maximum aerobic power of trained from untrained subjects in core groups whose different abilities could not otherwise be distinguished by the A-R nomogram itself. In a validation group of trained (n = 5), untrained (n = 5), and moderately trained (n = 4) 20- to 29-yr-old males, the correlation measured between VO2max values and those predicted from the new nomogram was significantly better (r = 0.98) (P less than 0.05) than predictions made from the A-R nomogram (r = 0.80).