Inclusion Criteria:  Aged 30 years old to 65 years old. Either STOP-Bang score of ≥3 or Epworth sleepiness scale indicating mild excessive daytime sleepiness to severe excessive daytime sleepiness (11-24 points). Has pre-existing diabetes mellitus and/or hypertension and is on medication. Ability to provide informed consent. Not working night shift.  Exclusion Criteria:  Significant arterial disease due to the risk of limb ischaemia and necrosis. Not pregnant and not planning to get pregnant before the end of the study. History of psychiatric disease. Patient who are on wheelchair. Patient who has cardiac failure and or stroke. Patient who has end-stage renal failure. Estimated glomerular filtration rate <15ml/min/1.73m2 or on renal replacement therapy i.e. dialysis or renal transplant. Patient who has liver disease. Patient who are on pacemaker, and metal implants. Patient who are on CPAP treatment for OSA. Patient who are illiterate. Medications which affect fluid balance or level of consciousness (e.g. diuretics, non- steroidal anti-inflammatory drugs (NSAIDS), corticosteroids, sedatives, opiates) at any time during the study.