What causes dizziness in a patient after performing squats or squatting down, considering potential underlying conditions such as orthostatic hypotension, anemia, or cardiac issues?

Dizziness After Squats: Orthostatic Hypotension

Dizziness after squatting or performing squats is most commonly caused by orthostatic hypotension—a drop of at least 20 mmHg systolic or 10 mmHg diastolic blood pressure upon standing—resulting from inadequate compensatory mechanisms when blood pools in the lower extremities during the position change. 1, 2

Pathophysiology

When you squat or stand up from a squatting position, gravity causes blood to pool in the legs and lower body. Normally, the autonomic nervous system compensates through:

• Venous and arterial constriction 2
• Increased heart rate and cardiac contractility 2
• One-way valves in veins that promote venous return 2

When these mechanisms fail or are inadequate, cerebral perfusion drops, causing dizziness, lightheadedness, or even syncope 1, 2.

Key Causes to Evaluate

Non-Neurogenic Causes (Most Common)

• Medications: Diuretics, vasodilators, antihypertensives, and tricyclic antidepressants are frequent culprits 3
• Hypovolemia/Dehydration: Reduced intravascular volume from inadequate fluid intake, blood loss, or excessive diuresis 1, 2
• Cardiac pump failure: Heart failure reduces cardiac output and impairs compensatory responses 4
• Prolonged bed rest or deconditioning: Loss of postural reflexes from inactivity 3
• Anemia: Reduced red blood cell mass decreases oxygen delivery and may worsen orthostatic symptoms 5

Neurogenic Causes

• Diabetic autonomic neuropathy: Cardiac autonomic neuropathy (CAN) causes abnormal heart rate variability and orthostatic hypotension 3
• Parkinson's disease and neurodegenerative disorders: Multiple system atrophy and pure autonomic failure cause defective vasoconstrictor mechanisms 3, 6
• Peripheral autonomic neuropathies: From diabetes, systemic diseases, or other causes 3

Exercise-Specific Considerations

• Post-exercise hypotension: Blood vessels remain dilated after vigorous exercise, and venous pooling occurs when suddenly stopping 3
• Valsalva-like maneuver during squats: Breath-holding during heavy squats increases intrathoracic pressure, reducing venous return 3

Diagnostic Evaluation

Essential Initial Assessment

Measure orthostatic vital signs properly: Blood pressure and heart rate after 10 minutes supine, then at 1,2, and 3 minutes after standing 3. Orthostatic hypotension is confirmed by a drop of ≥20 mmHg systolic or ≥10 mmHg diastolic (≥30 mmHg systolic in hypertensive patients) 3, 2.

History Must Include

• Medication review: Particularly cardiovascular drugs, diuretics, and psychotropic medications 3
• Cardiovascular symptoms: Chest discomfort, palpitations, dyspnea, or exercise intolerance suggesting cardiac disease 3
• Timing and triggers: Symptoms only with squats/standing versus other positions, post-prandial timing, or after prolonged standing 3
• Diabetic complications: Duration of diabetes, presence of neuropathy, retinopathy, or nephropathy 3
• Autonomic symptoms: Permanent tachycardia, unfelt hypoglycemia episodes, post-prandial hypotension, or absence of nocturnal blood pressure dipping 3

Physical Examination

• Cardiac examination: Murmurs, signs of heart failure (rales, third heart sound, edema), or arrhythmias 3
• Volume status: Signs of dehydration or anemia 3, 1
• Neurological examination: Evidence of peripheral neuropathy or parkinsonian features 3, 6

When to Obtain ECG

An ECG is warranted if there are cardiovascular symptoms, abnormal cardiac examination, or risk factors for cardiac disease 3. Look for conduction abnormalities, prolonged QTc interval (>440 ms suggests autonomic neuropathy), or signs of ischemia 3.

Advanced Testing Indications

• Cardiac autonomic testing: Deep breathing test and Valsalva maneuver if diabetic with microangiopathic complications or symptoms suggesting autonomic neuropathy 3
• Echocardiography: If structural heart disease or heart failure is suspected 3
• Laboratory work: Complete blood count for anemia, metabolic panel for electrolytes and renal function 5

Management Approach

Non-Pharmacologic Interventions (First-Line)

Physical counter-pressure maneuvers during prodrome: Leg crossing, lower body muscle tensing, or squatting itself can temporarily increase blood pressure and cardiac output 3. These work best when the patient recognizes early symptoms.

Compression garments: At least thigh-high, preferably including the abdomen, improve orthostatic symptoms by preventing venous pooling 3.

Hydration and salt supplementation: Increase fluid intake and add 6-9 grams (1-2 teaspoons) of salt daily to expand plasma volume, unless contraindicated by heart failure or hypertension 3.

Acute water ingestion: Drinking ≥480 mL of water provides temporary relief within 30 minutes through a sympathetically-mediated pressor effect 3.

Modify exercise technique:

• Avoid sudden standing after squats; transition gradually through sitting 3
• Avoid breath-holding (Valsalva) during heavy lifts 3
• Maintain adequate hydration before and during exercise 3

Medication Adjustments

Review and reduce offending medications: Diuretics, vasodilators, and antihypertensives should be minimized or discontinued if possible 3, 1.

Pharmacologic Treatment (For Neurogenic OH)

Midodrine: 2.5-10 mg three times daily improves standing blood pressure through alpha-agonist vasoconstriction; watch for supine hypertension, scalp tingling, and urinary retention 3.

Droxidopa: 100-600 mg three times daily for neurogenic orthostatic hypotension from Parkinson's disease, pure autonomic failure, or multiple system atrophy; may cause supine hypertension, headache, and dizziness 3.

Fludrocortisone: 0.1-0.3 mg daily increases plasma volume but should be used only when supine hypertension is absent; monitor for edema, hypokalemia, and adrenal suppression 3.

Special Considerations

In diabetic patients with autonomic neuropathy: Avoid medications that worsen orthostatic hypotension, obtain ambulatory blood pressure monitoring to detect non-dipping patterns, and optimize glycemic control 3.

In heart failure patients: Fludrocortisone and midodrine are problematic due to fluid retention and increased afterload; rely primarily on non-pharmacologic measures 4.

In anemic patients with autonomic failure: Erythropoietin treatment can improve both anemia and orthostatic hypotension by increasing red blood cell mass and blood pressure 5.

Red Flags Requiring Urgent Evaluation

• Syncope during exercise: Suggests cardiac arrhythmia or structural heart disease requiring immediate cardiovascular assessment 3
• Chest pain or dyspnea: Possible cardiac ischemia or heart failure 3
• New neurological symptoms: Diplopia, limb weakness, or speech difficulties suggest stroke or seizure 3
• Severe bradycardia or ECG abnormalities: May require urgent pacing or treatment 3