The investigators will recruit children with sleep apnea who are obese and test for heart disease risk. The investigators will then treat these children with CPAP. After 6 months of CPAP, the investigators will repeat the tests to determine if CPAP lowers the risk for heart disease. At the end of the 6 months, those receiving CPAP will be randomized to either continue CPAP or discontinue CPAP for a 2 week period. At the end of the 2 week period the participants will repeat the tests again to determine the magnitude of the effect of CPAP.