What Are the Causes of Dizziness & Blackouts?

Dizziness and blackouts are symptoms of many medical conditions 13. They occur when not enough blood reaches the brain or when there are electrical disturbances in the brain. Most causes can be treated successfully, but some are more serious.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.


Dizziness is a feeling of faintness, feeling light-headed, and spinning or rocking movements when you're still 13. Blackouts, also called syncope, are a loss of alertness or awareness lasting only a few minutes.

Treatable Causes


Serious Causes

There are usually other symptoms with serious illnesses, including chest pain, headaches, vision changes and speech difficulties.


Drugs used for nasal congestion, allergies, high blood pressure and anxiety can cause dizziness or blackouts 13. Alcohol use and illegal drug use are other causes.

The Wrap Up

A drop in blood pressure or blood sugar levels are common causes, and coughing, ear infections, fever, colds and allergies can cause dizzy spells and loss of awareness 1. Standing in one place for too long, straining during bowel movements, fatigue, hyperventilating, standing up suddenly, and dehydration from the flu or other illnesses can lead to dizziness and blackouts 13. Central nervous system diseases, irregular heartbeat, stroke, multiple sclerosis, seizures, brain tumors, and a heart attack can cause dizziness and blackouts 13.