Researchers from Mercer's Institute for Successful Ageing (MISA) and the Department of Medical Physics at St James's Hospital and Trinity College Dublin have discovered that brain tissue oxygenation is lower in frailer older adults with multiple health conditions (multi-morbidity), putting them at risk of faints and falls. Brain oxygenation - the measure of oxygen in brain tissue - reflects the balance between oxygen delivery and consumption and is vital for the maintenance of normal brain function and tissue integrity.