Guillain-Barré syndrome (GBS) is a neurological disease characterized by an inflammation of peripheral nerves, which might be responsible for long-term disability. Respiratory muscle weakness is a complication of GBS and might be responsible for respiratory symptoms, inadequate secretion clearance or hypoventilation, with negative impact on daily life. Inspiratory muscle training has been applied in respiratory and neurological diseases and benefits have been observed in symptoms (e.g., dyspnoea), pulmonary function, exercise capacity and quality of life. Nevertheless, results of this intervention in people with GBS are yet unknown. Moreover, rehabilitation is a key player in the recovery of these highly complex patients, however, the interpretation of the magnitude of its effects has been limited by the absence of minimal clinically important differences for most outcome measures. To overcome these drawbacks, methodologically robust trials are needed to build evidence-based rehabilitation to improve clinical care on GBS. The primary aim of this project (RehabGBs) is to develop an inspiratory muscle training protocol - InspireGBs and assess its effects on respiratory muscle strength, peak cough flow, pulmonary function, dyspnoea, fatigue, functional status and quality of life in people with GBS, through a randomised controlled trial. Secondary aims are to: i) establish minimal clinically important differences of Functional Assessment of Chronic Illness Therapy-Fatigue Subscale, Medical Research Council - Manual Muscle Testing, Vital capacity, Maximal Inspiratory Pressure, Peak Cough Flow, Functional Independence Measure and Quality of Life for inpatient rehabilitation programmes of people with GBS ii) Evaluate the prevalence of nocturnal hypoventilation in GBS.