Orthostatic Hypotension: This condition is characterized by a sudden drop in blood pressure when standing up or changing positions, which can lead to dizziness. Bending over can exacerbate this effect due to further decreases in blood pressure.

Benign Paroxysmal Positional Vertigo (BPPV): Although more commonly associated with specific head movements, some patients with BPPV may experience dizziness with bending due to the movement of otoliths in the inner ear.
Vasovagal Syncope: This condition can cause dizziness or fainting in response to certain triggers, including bending over, due to a sudden decrease in heart rate and blood pressure.
Dehydration: Inadequate fluid intake can lead to decreased blood volume, causing dizziness when bending over due to insufficient blood flow to the brain.

Cardiac Conditions (e.g., Aortic Stenosis, Cardiac Tamponade): Certain heart conditions can cause dizziness with exertion or position changes, including bending over. Missing these diagnoses could be fatal.
Subclavian Steal Syndrome: A rare condition where the subclavian artery is narrowed or blocked, potentially causing dizziness or syncope with arm exercise or certain positions, including bending over.
Cervical Spondylosis or Cervical Spine Stenosis: Compression of the spinal cord or vertebral arteries in the neck can lead to dizziness with neck movement, including bending over.

Chiari Malformation: A structural defect in the cerebellum that can cause dizziness, among other symptoms, particularly with certain head or neck movements.
Autonomic Dysfunction: Disorders affecting the autonomic nervous system, such as multiple system atrophy or pure autonomic failure, can lead to orthostatic intolerance and dizziness with position changes.
Inner Ear Disorders (e.g., Meniere's Disease, Labyrinthitis): While less commonly associated with bending over, these conditions can cause vertigo and dizziness that might be exacerbated by certain movements.