In the past two decades oxygenation responses to incremental ramp exercise, measured non-invasively by means of near-infrared spectroscopy at different locations in the body, have advanced the insights on the underpinning mechanisms of the whole-body pulmonary oxygen uptake ([Formula: see text]) response. In healthy subjects the complex oxygenation responses at the level of locomotor and respiratory muscles, and brain were simplified and quantified by the detection of breakpoints as a deviation in the ongoing response pattern as work rate increases. These breakpoints were located in a narrow intensity range between 75 and 90 % of the maximal [Formula: see text] and were closely related to traditionally determined thresholds in pulmonary gas exchange (respiratory compensation point), blood lactate measurements (maximal lactate steady state), and critical power. Therefore, it has been assumed that these breakpoints in the oxygenation patterns at different sites in the body might be equivalent and could, therefore, be used interchangeably. In the present review the typical oxygenation responses (at locomotor and respiratory muscle level, and cerebral level) are described and a possible framework is provided showing the physiological events that might link the breakpoints at different body sites with the thresholds determined from pulmonary gas exchange and blood lactate measurements. However, despite a possible physiological association, several arguments prevent the current practical application of these breakpoints measured at a single site as markers of exercise intensity making it highly questionable whether measurements of the oxygenation response at one single site can be used as a reflection of whole-body responses to different exercise intensities.

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Lower physical fitness level, more deconditioning and lower health-related QOL in children after LT emphasize the importance of exercise stimulation and fitness programs. Patients on antihypertensive medication seem to be the most vulnerable group suffering from decreased physical fitness.

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Background Few studies demonstrate delayed recovery after exercise in children and adults with heart disease. We assess the recovery patterns of gas exchange parameters and heart rate (HR) in children with repaired Tetralogy of Fallot (rToF) compared to healthy peers and investigate the correlation with ventricular function and QRS duration. Methods 45 children after rToF and 45 controls performed a maximal incremental cardiopulmonary exercise test. In the subsequent recovery period, patterns of VO2, VCO2 and HR were analysed. Half-life time (T1/2) of the exponential decay and drop per minute (Recmin) were compared between groups. In the rToF group, correlations were examined between the recovery parameters and QRS-duration and ventricular function, described by fractional shortening (FS) and tricuspid annular plane systolic excursion (TAPSE) measured at baseline prior to exercise. Results Recovery of VO2 and VCO2 was delayed in rToF patients, half-life time values were higher compared to controls (T1/2VO2 52.51 ±11.29 s vs. 44.31 ± 10.47 s; p = 0.001 and T1/2VCO2 68.28 ± 13.84 s vs. 59.41 ± 12.06 s; p = 0.002) and percentage drop from maximal value was slower at each minute of recovery (p<0.05). Correlations were found with FS (T1/2VO2: r = -0.517; p<0.001; Rec1minVO2: r = -0.636, p<0.001; Rec1minVCO2: r = -0.373, p = 0.012) and TAPSE (T1/2VO2: r = -0.505; p<0.001; Rec1minVO2: r = -0.566, p<0.001; T1/2VCO2: r = -0.466; p = 0.001; Rec1minVCO2: r = -0.507, p<0.001), not with QRS-duration. No difference was found in HR recovery between patients and controls. Conclusions Children after rToF show a delayed gas exchange recovery after exercise. This delay correlates to ventricular function, demonstrating its importance in recovery after physical activity.

Patients with mild CF lung disease have good exercise performance although still lower than the normal population. VO2max% is affected by number of antibiotic treatments over a longer period. There is an impact of hospitalization days on quality of life. What is Known: • Children with CF have lower exercise performance; there is an association between hospitalization frequency and exercise performance • Quality of life is diminished in children with CF and influenced by respiratory infections What is New: • Even patients with mild CF lung disease have lower maximal exercise performance (VO max) and a lower anaerobic threshold; VO max is lower in children who had more antibiotic treatments in the last 3 years • School and emotional functioning are diminished in children with mild CF lung disease; hospitalization is negatively correlated with school functioning and physical functioning.

Background: Physical fitness is an important determinant of quality of life (QOL) after hematopoietic stem cell transplantation. Cardiac function can influence exercise performance. The aim of this study was to assess these factors and their interrelationship. Procedure: Children underwent cardiopulmonary exercise testing (CPET) at least 1 year after hematopoietic stem cell transplantation (HSCT) and were compared with healthy controls. Systolic and diastolic heart function and left ventricle (LV) wall dimensions were measured. Healthrelated QOL (HR-QOL) was evaluated using PedsQL questionnaires.Results: Forty-three patients performed CPET (26 boys, 13.6 ± 3.4 years, weight 45.5 ± 13.3 kg, length 152.9 ± 17.5 cm, body surface area 1.35 ± 0.28). HSCT patients had lower maximal oxygen consumption (VO2peak/kg, 34.7 ± 8.4 vs 46.3 ± 7.1 mL/kg/min, P < 0.001), shorter exercise duration (9.1 ± 2.5 vs 12.9 ± 2.6 min, P < 0.001), and lower maximal load (%Ppeak 70.8 ± 19.7 vs 102.4% ± 15.9%, P < 0.001). Echocardiography demonstrated decreased interventricular septal wall thickness (interventricular septum in diastole [IVSd] Z-value −0.64 ± 0.69, P < 0.001), and more systolic (11% of patients) and diastolic dysfunction (high E/E' Z-value 1.06 ± 1.13, P < 0.001).LV dilatation correlates with VO2max/kg (r = −0.364, P = 0.017). HR-QOL showed lower overall and emotional functioning scores (respectively, P = 0.016 and P = 0.001). Patients after anthracycline therapy have the lowest maximal exercise performance, but have no difference in QOL.Diminished exercise performance is not encountered as a QOL limitation. Total body irradiation influences the domain of psychosocial functioning. Conclusions: LV (systolic and diastolic) and right ventricle dysfunctions justify the need for thorough cardiac follow-up in children after HSCT. Lower physical fitness levels and lower HR-QOL emphasize the importance of CPET and fitness programs. K E Y W O R D S cardiac function, exercise performance, hematopoietic stem cell transplantation, quality of life Abbreviations: CPET, cardiopulmonary exercise testing; GvHD, graft-versus-host disease; EF, ejection fraction; FS, fractional shortening; HR, heart rate; HR-QOL, health-related quality of life; HSCT, hematopoietic stem cell transplantation; LV, left ventricle; LVEDd, left ventricular end diastolic diameter; LVESd, left ventricular end systolic diameter; PedsQL, Pediatric Quality of Life Inventory; QOL, quality of life; RER, respiratory exchange ratio; TAPSE, tricuspid annular plane systolic excursion; TBI, total body irradiation; VAT, ventilatory anaerobic threshold

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