Evaluation of Physiological and Psychological Factors Involved in Exercise Intolerance in Patients With β-TTD

Inclusion Criteria: * Patients aged 18 years or older * Patients with transfusion-dependent β-thalassaemia (B0 or B+) * Patients who have undergone blood transfusions at intervals of between 1 and 8 weeks for at least 5 years. * Have given their free and informed written consent after being informed of the purpose of the study, its conduct and its risks. * Be affiliated with a social security scheme. * Not participating in any other interventional studies during the duration of this study Control subjects must meet all of the following criteria to participate in the study: * Subject aged 18 years or older * Matched in age and gender to a βTTD patient included in the study. * Declaring to be free of known acute or chronic pathologies. * Have given their free written consent after being informed of the purpose of the study, its conduct and its risks. * Be affiliated with a social security scheme. * Not participate in any other interventional study during the duration of this study. * Have 'low' or 'moderate' IPAQ results (inactive or slightly active). Exclusion Criteria: * \- Having received a bone marrow transplant. * History of thromboembolic disease. * Hospitalised for cardiac decompensation in the last 12 months. * Lack of use of limbs (amputee, paraplegic, quadriplegic) * Unable to comply with protocol requirements for social, family or other reasons, as determined by the investigator. * Known concomitant medical condition that could affect compliance with the protocol * benefiting of enhanced protection, namely minors, persons deprived of their liberty by judicial or administrative decision, adults under legal protection and, finally, patients in emergency situations. * Unable to give consent. * Pregnant or breastfeeding women.