To evaluate exercise tolerance and the reproducibility of the six minute walk test in children and adolescents with ESRD on regular hemodialysis and to compare their functional exercise capacities with reference values for healthy children. To investigate predictors of poor 6MWT performance in children on regular HD

The six-minute walk test (6MWT) is a submaximal test that assesses the functional exercise capacities of healthy subjects or those with a chronic disease, as well as the effects of interventions, such as pulmonary rehabilitation or drug therapies. It can predict prognosis, mortality and morbidity in adults and children with lung and/or heart diseases . A study with of children with stage V chronic kidney disease (CKD) has used the 6MWT to demonstrate decreased exercise tolerance , which appears to be caused by several factors, such as anemia, metabolic acidosis, electrolyte imbalance, osteopenia, growth deficiency, malnutrition, inactivity, uremic muscle dysfunction and associated comorbidities . The findings of this study suggest that the 6MWT could be used as a clinical tool to monitor functional exercise capacity in children with kidney disease. The 6MWT is a sub-maximum effort test that is more representative of daily life activities than other effort tests and has low cost and easy applicability . The distance walked in the 6MWT shows an association with VO2 peak, making it a viable and safe alternative for patients who cannot tolerate the ergometric test .

Inclusion Criteria:

• Children with ESRD who on regular hemodialysis at Assiut University Children Hospital .

Exclusion Criteria:

• Any subject with underlying primary cardio-pulmonary disease or condition that interfere with the walk test as hemiplegia and cerebral palsy.

The patient observed the researcher performing the test and then was instructed to walk as far as possible for 6- min and maintain a normal walking pace. Patients are able to interrupt the test if necessary. At each minute of walking the researcher communicated clearly and calmly how many minutes remained until the end of the test. In the end, the walked distance will be measured. HR, %HRmax, SpO2, SBP, and DBP delta values are to be measured before and after participating test.

During the test the researcher will monitor the patient for untoward signs and symptoms while using a stop watch to calculate time of the walked distance.If the patient stops before the 6 minutes are up and refuse to continue or the researcher decide that they should not continue, the researcher must wheel the chair over for the patient to sit on, discontinue the walk and note on the worksheet the distance , the time stopped and the reason for stopping prematurely.