Human body composition refers to the relative proportions of fat, bone, water, muscle and minerals in the body. Adequate proportions of these are a primary requirement for healthy living. Measurement of body composition is important for medical diagnosis and for understanding the physiological proportions of body tissues for physical fitness and exercise performance. Studies in human body hydration, as an example, provides the information necessary to understand the desired fluid levels for optimal performance of the body's physiological and metabolic processes during exercise and activities of daily living. It can help identify, or quantify issues of ill-health or wellbeing, e.g. lymphoedema and risk of heart attack. This thesis proposes a new system for assessing human body hydration which measures changes in body fluid level in real time.