An exploratory study of cardiac function and oxygen uptake during cycle ergometry in overweight children.
OBJECTIVE
Obesity has been proposed to negatively impact cardiac function in overweight (OW) individuals. The relationship between diastolic dysfunction and oxygen uptake (Vo(2)) kinetics is equivocal. This exploratory investigation evaluated the relationship between resting left ventricular function and Vo(2) kinetics during cycle ergometry in OW and non-overweight (NO) children and adolescents.


METHODS
Fourteen OW (>85 percentile for BMI for age and gender) children, 10 boys and 4 girls (age, 11.7 +/- 1.9 years; body mass, 80.6 +/- 45.5 kg) and 10 NO children (4 boys, 6 girls) volunteered to participate in the study (age, 12.5 +/- 2.1 years; body mass, 45.8 +/- 13.8 kg). Resting cardiovascular structure and function were assessed using spectral Doppler echocardiography. All subjects underwent two sub-maximal exercise stages on a cycle ergometer (3 minutes unloaded and 5 minutes at 50 W, both at a cadence of 50 rpm). Respiratory data were measured on a breath-by-breath basis at both workloads and the mean response time (MRT) was calculated.


RESULTS
Analysis of the MRT data demonstrated that there were no significant differences between OW and NO (OW, 52.6 +/- 11.7 seconds vs. NO, 45.6 +/- 7.4 seconds). Significant correlations (p < 0.05) were obtained between MRT Vo(2) and echocardiographic-derived mitral valve inflow pressure half-time (r = 0.55) and between MRT Vo(2), and mitral valve inflow deceleration time (r = 0.55).


CONCLUSIONS
The evidence from this research suggests a possible link between left ventricular diastolic function at rest and oxygen uptake kinetics during sub-maximal exercise in OW and NO children and adolescents.
Unnithan
Viswanath B
VB
Sport Department, Liverpool Hope University, Hope Park, Liverpool, L16 9JD, United Kingdom. unnithv@hope.ac.uk
Baynard
Tracy
T
Potter
Christopher R
CR
Barker
Piers
P
Heffernan
Kevin S
KS
Kelly
Erin
E
Yates
Greg
G
Fernhall
Bo
B
D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D004452:Echocardiography; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000502:physiology*; D006801:Humans; D008297:Male; D050177:Overweight / Q000503:physiopathology*; D010101:Oxygen Consumption / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology