What causes dizziness while running?

Dizziness While Running: Causes and Clinical Approach

Dizziness during running is most commonly caused by dehydration, inadequate fluid intake, exercise-induced hypotension, or gastrointestinal distress from nutritional factors—all of which are benign and preventable with proper hydration strategies and training.

Primary Physiological Causes During Exercise

Cardiovascular and Hydration-Related Causes

• Dehydration and inadequate fluid intake are leading causes of dizziness during endurance exercise, potentially exacerbating symptoms through reduced blood volume and compromised perfusion 1

• Exercise-induced hypotension occurs when blood is shunted to working muscles, reducing cerebral perfusion and causing presyncope or lightheadedness during or immediately after running 1

• Excessive fluid consumption can paradoxically cause exercise-associated hyponatremia (EAH), presenting with subtle symptoms like nausea, headache, or dizziness that can progress to altered mental status 1

• Athletes should monitor body weight before and after training runs, aiming to lose no more than 2-3% of pre-training weight, though EAH has been documented even in athletes who lost weight 1

Nutritional and Gastrointestinal Factors

• High-osmolality beverages (>500 mOsm/L) and concentrated carbohydrate solutions can cause gastrointestinal symptoms including nausea and dizziness by delaying gastric emptying and shifting fluids into the intestinal lumen 1

• Fiber, fat, protein, and fructose ingestion before or during running are associated with increased gastrointestinal distress that may manifest as dizziness 1

• Multiple transportable carbohydrates (glucose plus fructose) reduce gastrointestinal symptoms compared to single carbohydrate sources when consumed during endurance events 1

When to Consider Vestibular or Central Causes

Red Flags Requiring Urgent Evaluation

While most exercise-related dizziness is benign, certain features mandate immediate assessment for serious pathology:

• Focal neurological deficits, sudden hearing loss, inability to stand or walk, or new severe headache require immediate imaging and neurologic consultation 2, 3

• True vertigo (sensation of spinning or rotation) rather than lightheadedness suggests vestibular pathology and warrants different evaluation 1, 2

• Persistent symptoms at rest or symptoms unrelated to exercise intensity suggest underlying vestibular or neurologic disorders rather than exercise-induced causes 2, 3

Distinguishing Exercise-Related from Vestibular Dizziness

• Exercise-related dizziness typically occurs during or immediately after exertion, resolves with rest and hydration, and correlates with exercise intensity 1

• Brief episodic vertigo (seconds to minutes) triggered by head movements suggests benign paroxysmal positional vertigo (BPPV), which can be diagnosed with the Dix-Hallpike maneuver 2, 3, 4

• Vestibular migraine presents with attacks lasting hours, often with photophobia and phonophobia, and may be triggered by exercise but is not limited to it 1, 3

Practical Prevention and Management Strategies

Hydration Protocol

• Develop an individualized hydration plan during training by measuring body weight before and after long runs in various environmental conditions 1

• Avoid both excessive fluid restriction and overhydration—athletes should not gain weight during exercise and ideally lose no more than 2-3% of body weight 1

• Point-of-care sodium testing should be available at mass endurance events for athletes presenting with confusion or altered mental status 1

Nutritional Modifications

• Avoid high-fiber, high-fat, and high-protein meals before running, as these delay gastric emptying and increase symptom risk 1

• Use multiple transportable carbohydrate beverages (glucose plus fructose) rather than single carbohydrate sources during prolonged runs to minimize gastrointestinal distress 1

• Limit beverage osmolality to <500 mOsm/L to reduce gastrointestinal symptoms 1

Training Adaptations

• Progressive training is the primary method to reduce mechanical causes of dizziness, as the body adapts to the cardiovascular demands of running 1

• Implement heat acclimation protocols when training in warm environments, as heat stress compounds dehydration-related dizziness 1

Critical Pitfalls to Avoid

• Do not assume all exercise-related dizziness is benign—failure to identify red flags like focal neurologic deficits or sudden hearing loss can miss serious pathology including posterior circulation stroke 2, 3

• Do not rely on patient descriptions of "spinning" versus "lightheadedness" alone; focus on timing, triggers, and associated symptoms to guide evaluation 2, 3, 4

• Do not order routine imaging for isolated exercise-related dizziness without red flags, as diagnostic yield is extremely low (<1% for CT) 2

• Recognize that 75-80% of posterior circulation strokes present without focal neurologic deficits on standard examination, so maintain high suspicion if symptoms are atypical or persistent 2, 3, 4