Case Study: Causes for Lightheadedness
What causes the feeling of lightheadedness upon standing – and when should you be worried?
Q: Whenever I get up lately,I feel dizzy like I’m going to pass out. What is going on?
A: Dr. Zachary Levine: What you are describing sounds like presyncope, which means feeling lightheaded. Lightheadedness upon getting up is most often caused by a drop in blood pressure (orthostatic hypotension) and thereby blood supply to the head and brain. While it is normal to have a slight drop in blood pressure when one gets up because of pooling of blood in the lower part of the body, in most people there are mechanisms to offset this, such as the heart beating more strongly or the blood vessels constricting. When these mechanisms don’t work well, people are prone to orthostatic hypotension.
The condition is more common as one ages (corrective mechanisms sometimes do not work as well) and in people who have low blood pressure at baseline. Factors that could make the condition worse include dehydration, certain antidepressant and blood pressure-decreasing medications and illnesses such as gastroenteritis, atherosclerosis (plaque build-up in arteries), Parkinson’s disease and diabetes. Treatment of orthostatic hypotension depends on the underlying health problem – dehydration or heart failure, for example, which your doctor will address rather than the low blood pressure itself.
In the meantime, for mild orthostatic hypotension, one of the simplest treatments is to sit or lie down immediately after feeling lightheaded upon standing. and remember to drink enough water and get up slowly to decrease the risk of falls.
Dr. Zachary Levine is an Assistant Professor in the Faculty of Medicine at McGill University Health Centre and medical correspondent for AM 740
(a ZoomerMedia property).
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