Recovery kinetics of heart rate and oxygen uptake in long-term survivors of acute leukemia in childhood

Analysis of the recovery period following physical exercise has gained importance in evaluating cardiopulmonary capacity, not only in athletes but also in patients with proven or suspected heart failure. The purpose of this study was to apply these methods to long-term survivors of acute lymphoblastic leukemia (ALL) in childhood, who are at risk of developing anthracycline-induced cardiomyopathy. Nine children (mean age 12 years) and 10 adults (mean age 24 years) were included in the study after treatment for childhood ALL. Recovery of oxygen uptake and heart rate following maximal spiroergometric exercise was compared to that in 29 trained and untrained age-matched controls. The change in oxygen uptake (ΔVO₂) and heart rate (ΔHR) between maximal effort and 60 s of recovery did not differ significantly, either between children after oncological therapy (ΔVO₂: 14.95 ml/kg, ΔHR: 35 bpm) and healthy children (ΔVO₂: 15.85 ml/kg, ΔHR: 37 bpm), or between adult former oncological patients (ΔVO₂: 13.1 ml/kg, ΔHR: 27 bpm) and untrained adults (ΔVO₂: 15.7 ml/kg, ΔHR: 31 bpm). There was, however, a significant difference in ΔVO₂ between trained adults (ΔVO₂: 24.5 ml/kg) and both untrained adult controls (ΔVO₂: 15.7 ml/kg, p = 0.004) and adult patients (ΔVO₂: 13.1 ml/kg, p = 0.0002). This difference was not detected for heart rate. In conclusion, the recovery period did not reveal a discernible difference in cardiopulmonary capacity between former ALL patients and untrained age-matched controls. We did confirm that heart rate and oxygen uptake recovery serve as indicators of physical fitness.