Water Immersion in Chronic Stable Heart Failure

Inclusion Criteria: * Age \>18 * Established diagnosis of heart failure with NTpro BNP \>100 Exclusion Criteria: * Uncontrolled or severe heart failure, defined by NYHA class IV symptoms (breathlessness at rest) * Severe fluid overload characterised as more than minimal pitting oedema of the ankles only * Presence of haemodynamically significant valvular heart disease in the opinion of the investigator * Haemoglobin \<125 g/L * Weight \>120 kilograms * Requiring long term oxygen supplementation in the community * Hospitalisation for any cause within the last 6 weeks, that in the opinion of the investigator would affect the patients wellbeing in this study * Unstable or severe stable angina that requires three or more antianginals * Patients known to have disease causing immunocompromise such as HIV infection or undergoing chemotherapy * Patients with active infection * Dialysis patients * Uncontrolled seizures; patients in whom the pool environment may trigger seizures, new diagnosis of epilepsy * Insulin treated diabetic patients with hypoglycaemic episodes in the last 3 months. * Pregnant women * Central venous lines which are not tunnelled and are exposed superficially. * Open access ports to lungs including tracheotomy sites * Ventilation tubes for ears * Nasogastric or gastrostomy tube in situ * Presence of colostomy, ileostomy or urostomy. * Presence of open, macerated, infected or non-intact skin or oedema with leakage of serous fluid. * Skin condition such as severe eczema or psoriasis * Any surgery or invasive devices fitted within the last 4 weeks * Any form of mobility impairment requiring mobility aids (e.g. stick or wheelchair) or rendering patient unable to perform gentle exercises, including recent injury or trauma * History of chlorine sensitivity * Urinary or faecal incontinence * Hydrophobia * Unable to give consent