Cardiovascular responses to treadmill exercise testing in anemia.

OBJECTIVE To study exercise performance on a treadmill in anemic children. DESIGN Prospective case control study. SETTING Department of Pediatrics and Intensive Care Unit, Department of Medicine, King George's Medical College, Lucknow. SUBJECTS The study population consisted of 41 cases of anemia (10 mild, 21 moderate and 10 severe) and 11 normal age and height matched children aged between 7-12 years. METHODS These subjects were exercise tested on Quinton Model Q5000 treadmill using Modified Naughton Q5000 protocol. Heart rate, systolic blood pressure, double product, ECG changes, exercise duration and metabolic equivalents achieved during peak exercise were studied. Statistical analysis was performed using analysis of variance (ANOVA) test. RESULTS No significant difference was observed in values of resting heart rate, heart rate at peak exercise, recovery heart rate, blood pressure response, resting double product, double product at peak exercise, recovery double product and ECG changes in any of the study groups (p > 0.05). However, the gain in heart rate at peak exercise compared to basal value, and double product, total exercise duration and metabolic equivalent (MET) values at peak exercise were significantly low in anemic children on comparison to normal controls (p < 0.001). CONCLUSIONS Cardiovascular responses are blunted in anemia, mainly because of depleted cardiac reserve.