Within 5‐year off‐chemotherapy: How the cardio‐respiratory response to exercise is related to energy expenditure, fatigue, and adiposity in children with acute lymphoblastic leukaemia?

Objective To explore the cardio‐respiratory response to exercise and examine the relationships among specific measures of cardio‐respiratory function, energy expenditure (EE), fatigue and adiposity in children survivors of acute lymphoblastic leukaemia (ALL). Methods Seventy survivors of ALL (13.31 ± 2.60 years) and 34 controls from the siblings (12.71 ± 2.36 years) participated and were assessed for submaximal and maximal exercise capacity, body composition, EE and fatigue. Results ALL survivors had significantly lower submaximal (VO 2 ; p  = 0.002) and maximal (VO 2peak ; p  ˂ 0.001) cardio‐respiratory capacity than their controls. At the submaximal exercise test, EE was significantly lower in ALL survivors ( p  < 0.001), but the heart rate (HR) was significantly higher ( p  = 0.005). The VO 2 and HR were significantly correlated [ r (95%CI) = 0.689 (0.542 to 0.795), p  < 0.001]. The VO 2peak negatively associated with adiposity [ r (95%CI) = −0.368 (−0.554 to −0.145), p  = 0.002]. Fatigue significantly correlated with the VO 2peak [ r (95%CI) = 0.581 (0.401 to 0.718), p  < 0.001] and adiposity [ r (95%CI) = −0.303 (−0.502 to 0.073), p  = 0.012]. Conclusion Children survivors of ALL experience low cardio‐respiratory fitness within 5‐year off‐chemotherapy. Associations exist between measures of cardio‐respiratory fitness, EE, fatigue and adiposity. However, it has not yet been proven whether these are cause or effect.