The individual relationship between heart rate and oxygen uptake in people with a tetraplegia during exercise

Study design: Descriptive study. Objective: To examine the individual heart rate - oxygen uptake (HR - VO2) relationship during exercise in persons with tetraplegia (TP). Setting: Rehabilitation Centre Heliomare, Wijk aan Zee, The Netherlands. Methods: The HR - VO2 relationship was determined in untrained subjects with motor complete TP (C5 or C6, n = 10 and C7 or C8, n = 10) during a discontinuous graded exercise hand cycle test. The mean HR and VO2 of the final 60 s of 2-min exercise blocks were used for calculation of the individual correlation coeffcient and the standard error of the estimate (SEE). Results: Two subjects of the C5 - C6 group were not able to complete the test. Individual Pearson's correlation coefficients (r) ranged from 0.68 to 0.97 and SEE from 2.6 to 22.4% VO2-Reserve (VO2R). The mean Pearson's r and SEE were 0.81 +/- 0.12 and 10.6 +/- 5.6% VO2R in the C5 - C6 group and 0.91 +/- 0.07 and 7.0 +/- 3.2% VO2R in the C7 - C8 group, respectively. Two subjects of the C5 - C6 group and six subjects of the C7 - C8 group attained a linear HR - VO2 relationship with an acceptable SEE (<= 6.0%) and r (> 0.90). Conclusions: The HR - VO2 relationship appeared linear in only eight out of 18 subjects. An individual analysis of the HR - VO2 relationship is necessary to determine whether HR can be used to quantify exercise intensity. The use of HR to prescribe training intensity should be reconsidered in persons with TP.