Q: Last week my husband fainted while standing up from the
dinner table. He is in his early 50s and healthy. What could have
caused him to faint, and how concerned should we be?
Q: Last week my husband fainted while standing up from the dinner table. He is in his early 50s and healthy. What could have caused him to faint, and how concerned should we be?
A: The most common causes of fainting are conditions that temporarily deprive the brain of the blood it needs. Organs require a certain amount of blood to function. The brain is particularly sensitive to any shortages, and your cardiovascular system has to fight gravity to keep a shortage from happening. The simple act of standing up causes a quarter of your blood supply to plummet toward your legs and the lower part of your body. If your body did nothing to fight the effects of gravity, blood flow to your brain would be reduced. But your body does compensate. The autonomic part of your nervous system causes your heartbeat to speed up by 10 to 15 beats per minute and your smallest arteries to narrow, like someone squeezing a hose. Blood pressure increases, so more blood is pushed into the brain. One reason older people faint more is that the various sensors and reflexes responsible for all of this fine-tuning become less sensitive and a bit slower with age.
Going to the bathroom and eating (or more precisely, the ensuing digestion) can be triggers. Anything that lowers the amount of blood in your body can set the stage for a swoon: bleeding, dehydration from hot weather or from not getting enough fluids, or kidney problems. Medications, particularly the diuretics used to control high blood pressure, can also decrease blood volume.
Psychological events like fear, strong sensations such as pain, and everyday occurrences like coughing or even laughing sometimes make someone faint. No one knows why. The nervous system’s “wires” may get crossed sending the wrong signal to the cardiovascular system.
Seizures, the result of abnormal electrical activity in the brain, are another potential cause of fainting. Certain inner ear disorders can also make you faint.
The conditions that cause these temporary drops in blood pressure go by several medical terms. Neurally mediated hypotension and vasovagal syncope (SIN-co-pee) are commonly used terms that apply to the same condition: a tendency to faint easily.
Starting at about age 50, the chances increase that fainting might be the sign of a potentially dangerous heart problem.
You should always inform your doctor of any fainting spells. While it may turn out to be a small problem, you want to be certain. If doctors suspect neurally mediated hypotension (vasovagal syncope) they may order a tilt-table test, to determine what happens to your heartbeat and blood pressure if you suddenly are made upright after lying down. If doctors suspect a heart problem, they often will order an EKG, a Holter monitor study (a measurement of your heart rhythm over many hours), or an event monitor study (a measurement of your heart rhythm at the moment you feel like you might faint). If doctors suspect a seizure, they may order a brain-wave study (an EEG).
Sometimes tweaking medications helps. Drugs that lower blood pressure can make people vulnerable to fainting because they slow the heartbeat (beta blockers, nitrates) or relax arteries (ACE inhibitors, calcium-channel blockers).
Some research suggests that antidepressants might help people who faint frequently. Researchers have also had some success “retraining” the nervous and cardiovascular systems of frequent fainters. In one study, the successful therapy was just a matter of standing up against a wall twice a day for 40 minutes.
If your husband ever feels as if he is going to faint again, that familiar advice to sit down and put your head between your legs actually makes pretty good sense. By sitting down he is avoiding a fall and by putting his head between his legs he is encouraging more blood flow to the brain. There are also some simple exercises he can try (see accompanying sidebar).
If your husband does actually faint again, the best thing you can do is to keep him flat on the ground until he wakes up. That way the cardiovascular system doesn’t have to fight gravity. You should also turn him on his side to prevent choking. It’s a mistake to sit people up after they faint because then the blood has to flow uphill to the brain. Also, watch very carefully to see if he makes any strange jerking movements just before or during his fainting spell, and note what part of the body was jerking. The doctor will want to know this information.
While most of the time, particularly in people under age 50, a fainting spell isn’t the sign of a serious medical problem, make sure that you tell the doctor: figuring out what’s serious requires a medical evaluation.
Submit questions to the Harvard Medical School Adviser at www.health.harvard.edu/adviser. Unfortunately, personal responses are not possible.
