Based on many previous data proving hypervolemia in chronic hemodialysis patients could lead to sleep apnea and poor sleep quality. The investigators conduct this trial to evaluate whether more accurate dry weight assessment with BIA in these patients can lead to better sleep quality (measured by sleep actigraphy and questionnaires). The investigators will enroll 30 chronic hemodialysis patients in hemodialysis unit of Ramathibodi hospital whose age > 18 years with subclinical hypervolemic status and baseline Pittsburgh sleep quality index (PSQI) score > 5 into study. Patients with bed-ridden status, alteration of consciousness and unstable hemodynamics will be excluded. Then eligible patients will be randomized into 2 groups, BIA-guided and standard clinical guided dry weight assessment. The investigators will assess participants' dry weight at beginning of study, 3rd month and 6th month. Sleep actigraphy parameters (eg. total sleep time, sleep efficiency), sleep questionnaires score, left ventricular mass index by echocardiography, ambulatory blood pressure monitoring and blood chemistry results were collected at beginning of study, the end of 1st, 3rd and 6th month. The primary outcome is change of sleep actigraphy parameters between the groups. The secondary outcomes are change of sleep questionnaires scores, change of left ventricular mass index, change of ambulatory BP monitoring and also cardiovascular complications between groups.