when dizziness is serious

Your dizzy spells are frequent or last longer than a few minutes.

A common condition called vertigo causes an “illusion of movement,” Cho explains. It’s caused by a disconnect between your ears and your brain, which results in a spinning sensation. Brief episodes can be triggered, most commonly, by rapid change in head movement, according to the Mayo Clinic. In most cases, especially in younger patients, the condition will resolve on its own, Cho says. But if you have it constantly, episodes that last hours at a time, or it’s accompanied by ringing in the ears or hearing loss, it could be a sign of a more serious ear disorder or undiagnosed migraines.
2. You’re also experiencing symptoms like numbness, weakness, speech problems, clumsiness, or vision problems.

You feel dizzy when you stand up.

Orthostatic hypotension—low blood pressure that happens when you stand up—can make you feel faint, but is usually nothing to worry about. The most likely cause is dehydration. “Especially in the summer months, people forget to drink more. You don’t have to be dripping sweat to become dehydrated,” Cho says. If loading up on H2O doesn’t stop these dizzy spells, there are some other disorders that could be causing low blood pressure or poor circulation, leading to dizziness. Cardiovascular disease (arrhythmias or congestive heart failure), and conditions that are most typical in diabetics—such as neuropathy (nerve damage) or hypoglycemia (low blood sugar)—can all cause this dizzy or lightheaded sensation.
. You have a history of migraines.

If your dizziness feels like your head is spinning (not the room), it could mean you’re suffering from migraines without knowing it, Cho says. Some people don’t realize their headaches are actually migraines if they don’t also see flashing lights or auras—but those symptoms are not always necessary.