Background: The identification of specific information in relation to intensity and duration of exercise that contributes to a meaningful reduction in signs or symptoms of lymphoedema will assist in the development of safe and beneficial exercise prescription recommendations. However, little is known about how exercising in a hydrotherapy pool will affect physiologic responses in women with secondary lower limb lymphoedema (LLLO). Aims: The aims of this study were to: 1) measure and compare the immediate physiological responses of a standardised AP program in women with secondary lymphoedema of the leg/s and healthy women; and 2) to determine if the responses were different depending on the duration of exercise (15, 30 and 45 minutes). Procedures: A sample of four women with secondary LLLO and two healthy women without lymphoedema was recruited. A repeated-measures, controlled trial design was implemented. Measurements of skin temperature and limb volume (perometry and bioimpedance spectroscopy) were taken prior to and immediately after exercising in the pool. Outcomes: Changes in skin temperature, limb volumetric measures and lymph fluid volume were observed to be similar between women with and women without lymphoedema. There was no significant skin temperature differences between symptomatic and asymptomatic legs. The relationship of physiologic response to duration of AP appeared to be stronger following 30 and 45 minute sessions than after the 15 minute session. A minimum duration of 30 minutes of AP appears to be most beneficial to women with secondary LLLO for reducing the size of the symptomatic leg.