Head-up Tilt Sleeping to Alleviate Orthostatic Hypotension, Supine Hypertension and Nocturia in Parkinson's Disease

Inclusion Criteria: * Orthostatic hypotension defined as a systolic BP decrease of ≥20 mmHg, or a diastolic decrease of ≥10 mmHg, within 3 min after changing from a supine to standing position OR mean standing BP of ≤75 mmHg (marker for symptomatic orthostatic hypotension). In patients with supine hypertension, a decrease in systolic BP of ≥ 30 mmHg is required; * Orthostatic intolerance: direct complaints (dizziness, blurry vision, etc.) and/or indirect signs (falls or freezing episodes that relate to postural challenge); * Supine hypertension defined as a systolic BP of ≥140 mmHg, and/or diastolic of ≥90 mmHg, after 5 min of supine rest; * Idiopathic PD or parkinsonism (multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, vascular parkinsonism and Lewy body dementia); * Ability to walk (with or without a walking aid), as subjectively determined by the researcher; * Stable medication regimens for orthostatic hypotension and supine hypertension during the trial; Exclusion Criteria: * Inability to follow instructions and complete questionnaires, as assessed by the researcher;