Lightheadedness on standing

Lightheadedness on standing is the momentary dizziness, wooziness, visual greying or near-faint feeling that comes as you get up from lying or sitting. When you stand, gravity pulls blood down into your legs, and the body normally responds instantly — tightening blood vessels and speeding the heart — to keep blood flowing to the brain. If that response is too slow or the blood volume or pressure is too low, the brain is briefly under-supplied, producing the lightheaded sensation. This is called orthostatic (postural) hypotension. Occasional mild episodes, especially standing up quickly on a hot day or after resting, are very common and usually harmless. But frequent, severe or worsening lightheadedness on standing can point to a cause worth finding: dehydration or blood loss (low volume), anaemia (too few red cells to carry oxygen), medication effects (especially blood-pressure and prostate drugs, diuretics and some antidepressants), diabetes or other conditions that affect the nerves controlling blood pressure (autonomic dysfunction), and hormonal problems such as adrenal insufficiency (Addison's disease). It matters particularly in older people, where it raises the risk of falls. The pattern — how severe it is, whether it causes actual fainting, and what else accompanies it — guides how far to look.

• Standing up quickly, heat, or after resting — brief, common and usually harmless.
• Dehydration or blood loss — low blood volume; a very common and reversible cause.
• Anaemia — too few red cells to carry oxygen, causing dizziness and breathlessness.
• Medications — blood-pressure and prostate drugs, diuretics, and some antidepressants.
• Autonomic dysfunction — nerve control of blood pressure impaired, as in diabetes or Parkinson's.
• Adrenal insufficiency (Addison's disease) — a hormonal cause, often with salt craving and fatigue.

Lightheadedness on standing is first assessed by measuring blood pressure lying and then standing, to confirm the pressure drop, and by reviewing medications, which are a very common and easily reversible cause. Blood tests help identify treatable contributors: a full blood count for anaemia, kidney function and electrolytes (sodium, urea) for dehydration or salt problems, and glucose or HbA1c, since diabetes can damage the nerves controlling blood pressure. If adrenal insufficiency is suspected — for example with fatigue, salt craving and low sodium — cortisol and related tests are checked. Mediora.AI can surface anaemia, dehydration or an electrolyte pattern on your results that may explain lightheadedness on standing; interpreting these alongside your blood-pressure readings belongs with your doctor.