Inclusion Criteria:  Healthy adults aged ≥18 (considering 18 is the age of legal consent). Fluent in English. Free of intellectual disability or cognitive impairment that would impair or impede the ability to give informed, explicit consent. Free of all exclusion criteria below.  Exclusion Criteria:  Unstable or un-managed cardiac/respiratory/metabolic conditions (i.e. condition must be diagnosed and being managed as per medical input to be classified as stable and managed). Neuro- musculoskeletal disorders. Acute musculoskeletal injury or impairment (including acute pain). Malignancy. Mental illness. Chronic infectious disease (Hep C/ HIV/ AIDS). Acute systemic infection or illness. Taking medication that affects cardiovascular function. Exclusion for any other reason deemed appropriate by the research team.