Validation of Respiration Rate Algorithms

Inclusion Criteria: * Young Healthy Volunteers * Participant is willing and able to give informed consent for participation in the study. * Male or Female, aged between 18 and 40 years old. * Older Healthy Volunteers * Participant is willing and able to give informed consent for participation in the study. * Male or Female, aged 70 years or above. * Patients * Participant is willing and able to give informed consent for participation in the study. * Male or Female, aged 18-70 years old. * Participant has one of the following conditions: * Atrial fibrillation * A permanent pacemaker that is continuously active * Reduced chest wall movement Exclusion Criteria: * Young Healthy Volunteers * Any condition which might increase the risk of exercise testing * Any history of ischaemic heart disease * Any history of heart failure * Any structural heart disease (eg: valvular lesions, hypertrophic obstructive cardiomyopathy) * Any abnormalities on a resting ECG * Deep vein thrombosis diagnosed within the last 6 months or under active treatment * Uncontrolled hypertension (systolic blood pressure \>220 mm Hg, diastolic \>120 mm Hg) * Aortic aneurysm * Aortic or cardiovascular surgery within 6 months of recruitment * A family history of sudden cardiac death, congenital arrhythmia syndromes or cardiomyopathy * Autonomic dysfunction, either previously diagnosed or upon testing by the research team * Any condition involving the brain or spinal cord * Diabetes * Alcohol consumption \> 21 units/week for women and 28 units/week for men or a history of previous alcohol dependence. * Acute kidney injury * Chronic kidney disease stage 4 or 5 * Any condition causing hepatic dysfunction * Presence of a permanent pacemaker (these participants would be eligible for the pacemaker group) * Reduced chest wall movement (these participants would be eligible for the reduced chest movement group) * Any acute infection requiring antibiotic treatment within 3 months of recruitment * Any other surgery or illness requiring hospitalisation within 3 months of recruitment * Currently taking any medication with the exception of analgesics or the oral contraceptive pill. * Any wound or skin condition affecting the torso which may be affected by the application of adhesive ECG dots to the skin * Pregnancy * Inability to give informed consent * Older Healthy Volunteers * Any diagnosed condition primarily affecting the cardiovascular or respiratory systems * Symptomatic autonomic dysfunction * Orthostatic hypotension * Any condition involving the brain or spinal cord * Diabetes * Alcohol consumption \> 21 units/week for women and 28 units/week for men or a history of previous alcohol dependence. * Acute kidney injury * Chronic kidney disease stage 4 or 5 * Any condition causing hepatic dysfunction * Presence of a permanent pacemaker * Chronic Obstructive Pulmonary Disease (COPD). * Any muscular dystrophy * Kyphosis * Scoliosis * Pectus excavatum * Any disease involving the lungs or pleura * Any acute infection requiring antibiotic treatment within 3 months of recruitment * Any other surgery or illness requiring hospitalisation within 3 months of recruitment * Currently taking any medication with the exception of analgesics or the oral contraceptive pill. * Any wound or skin condition affecting the torso which may be affected by the application of adhesive ECG dots to the skin * Pregnancy * Inability to give informed consent * Patients * Any infection which would require isolation or barrier nursing according to the hospital's infection control policy * Any wound or skin condition affecting the torso which may be affected by the application of adhesive ECG dots to the skin * Requirement for any form of artificial ventilatory support, including oxygen therapy * More than one of the inclusion criteria. (ie: a patient may not have both atrial fibrillation and reduced chest wall movement and be eligible for this study) * Inability to give informed consent