Takeaway
Orthostatic intolerance—when the body struggles to maintain blood flow to the brain while standing—is a common, treatable cause of chronic fatigue that is often missed. A methodical standing test combined with listening carefully to the patient's story can provide an accurate diagnosis.
Lifelong learning in clinical excellence | June 30, 2026 | 3 min read
By Maritsa Christoforou, research coordinator, Alba Azola, MD, and Peter Rowe, MD, Johns Hopkins Medicine
A 25-year-old elite athlete with joint hypermobility had the insidious onset of heat intolerance, lightheadedness, and unusual fatigue that interfered with consecutive days of training. She could only manage 20-30% of her previous training intensity and after a normal practice, had increased fatigue and difficulty concentrating for the next two days.
To investigate her symptoms, we performed a passive standing test in clinic. After five minutes supine, she stood leaning against the wall for 10 minutes, which provoked increased fatigue, brain fog, and lightheadedness, accompanied by a 42-beat increase in heart rate compared to supine values, consistent with postural tachycardia syndrome (POTS). Although her coaches thought her athletic underperformance was due to psychological causes, she was able to return to full function after increasing her sodium intake by four grams daily and adding methylphenidate as a vasoconstrictor.
When it’s more than fatigue
People with a substantial degree of chronic fatigue—including those with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID—frequently experience orthostatic intolerance (OI), one of the most common and treatable contributors to symptom burden in these conditions. They usually have a monotonously consistent pattern of symptoms, some of which result from suboptimal cerebral prefusion, including lightheadedness, trouble concentrating, fatigue, and headache. Others result from the excessive catecholamine response to that reduction in brain blood flow, such as palpitations, chest pain, sweating, nausea, and orthostatic dyspnea.
Orthostatic intolerance has been identified as a contributor to chronic fatigue across many other conditions, including comorbid inflammatory bowel disease, allergies (asthma, urticaria, facial flushing), eosinophilic esophagitis, GI motility disorders, post-cancer fatigue, migraine, multiple sclerosis, vascular compression and insufficiency syndromes, and even neuroanatomic abnormalities (Chiari malformation, cervical spine stenosis). Joint hypermobility appears to predispose people to OI. With standing, those with connective tissue laxity likely have excessive venous pooling, leading to reduced preload and reduced brain blood flow.
Ask about common situations
Chronic fatigue and OI symptoms can begin insidiously, or after a variety of acute infections, like SARS -CoV-2, Epstein-Barr virus, or influenza. In our experience, patients often under-report symptoms, mistakenly thinking that everyone experiences these problems. To aid accurate assessment of symptoms, we find it helpful to ask how patients feel in specific situations, like:
How do you feel standing in line at the store, at a concert, or waiting for the bus?
How do you feel taking a hot shower or in a warm environment?
How long could you stand still before needing to fidget, walk around, or sit down?
As we often joke, if an adolescent cannot tolerate more than five minutes at a shopping mall, they have an organic problem until proven otherwise.
A simple test can make a big difference
Many clinicians were taught to be suspicious of psychosomatic disorders in patients reporting more than three presenting problems, but this obviously would be an unfair rush to judgement in those with the range of autonomic symptoms seen in those with OI. Unfortunately, many patients with chronic fatigue endure years of medical gaslighting and fragmented specialty care without any reprieve from their daily symptom burden.
As Osler famously said, “Listen to your patient, he is telling you the diagnosis.” After you understand their story, the recipe is simple: a passive standing test, requiring a vitals machine, a blank wall, and just 17 minutes can bring answers to people who have spent years just searching for clues.
This piece expresses the views solely of the author. It does not represent the views of any organization, including Johns Hopkins Medicine.