Orthostatic Intolerance (OI) is a condition in which individuals experience a range of debilitating symptoms when standing upright, which often improve or resolve when they lie down. These symptoms include dizziness, lightheadedness, brain fog, rapid heartbeat, and fatigue. OI occurs when the body struggles to regulate blood flow and maintain adequate blood pressure in response to changes in posture, such as transitioning from sitting or lying down to standing.
In this context, The Life Improvement Trial (LIFT) is a clinical trial investigating two drugs—Pyridostigmine (commonly known as Mestinon) and Low Dose Naltrexone (LDN)—both separately and in combination. It seeks to explore their potential as treatments for ME/CFS and Orthostatic Intolerance, aiming to improve the quality of life for those affected by these conditions.
While OI can affect anyone, it is notably prevalent in individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID. Studies suggest that a significant percentage of people living with these conditions experience some type of orthostatic intolerance, such as Postural Orthostatic Tachycardia Syndrome (POTS) or Orthostatic Hypotension (OH).
In the context of ME/CFS and Long COVID, OI not only contributes to daily discomfort but also exacerbates other symptoms like cognitive dysfunction and post-exertional malaise (PEM). Recognizing and understanding OI is crucial for effective symptom management and improving the quality of life for those affected.
The Basics: Orthostatic Intolerance (OI)
What Is Orthostatic Intolerance?
Orthostatic Intolerance (OI) refers to the body’s inability to regulate blood pressure and heart rate effectively when standing. This dysfunction in the autonomic nervous system often leads to symptoms like dizziness, rapid heart rate, fatigue, and fainting, which improve when lying down.
In conditions like ME/CFS and Long COVID, OI is a significant contributor to daily impairment, making early recognition and targeted treatment essential.
Key Subtypes of OI
- Orthostatic Hypotension (OH): A significant drop in blood pressure upon standing, defined by a ≥20 mmHg decrease in systolic or ≥10 mmHg decrease in diastolic blood pressure within 3 minutes of standing. Symptoms often include dizziness, blurred vision, and fainting.
- Postural Orthostatic Tachycardia Syndrome (POTS): An abnormal increase in heart rate of ≥30 beats per minute (bpm) (or ≥40 bpm in adolescents) within 10 minutes of standing without a significant drop in blood pressure. Common symptoms include rapid heart palpitations, fatigue, and brain fog.
- Neurally Mediated Hypotension (NMH): A sudden drop in blood pressure triggered by prolonged standing or stress due to miscommunication between the brain and heart. It often results in fainting, dizziness, and extreme fatigue.
For an in-depth look at these subtypes, visit the OI syndromes resource.
Symptoms of Orthostatic Intolerance
OI presents a wide range of symptoms that can vary in severity and frequency. These Orthostatic Intolerance symptoms often worsen with prolonged standing or in warm environments and may improve when lying down. Common symptoms include:
- Lightheadedness, Dizziness, or Fainting: A common symptom of OI, these sensations occur when blood flow to the brain is reduced, often triggered by standing for long periods.
- Palpitations or an Increased Heart Rate: Many individuals experience a racing heartbeat or noticeable palpitations as the body tries to compensate for poor blood circulation.
- Headaches and Brain Fog: Headaches and difficulty concentrating are frequent in OI, often caused by reduced blood flow and oxygen delivery to the brain.
- Chronic Fatigue: Persistent tiredness is common in OI, even after rest, as the body works harder to regulate blood flow.
- Cold Hands and Feet: Poor circulation can lead to cold extremities, as blood pools in the lower body instead of circulating evenly.
- Muscle Aches and Nausea: Muscle discomfort and nausea may arise from inadequate blood flow and the physical strain of prolonged upright posture.
Recognizing these symptoms early is crucial for effective management and improving quality of life.
What Causes Orthostatic Intolerance?
Chronic Orthostatic Intolerance can arise from a combination of physiological imbalances and external triggers that affect the body’s ability to regulate blood pressure and heart rate.
Physiological Mechanisms
OI occurs when the autonomic nervous system fails to regulate blood flow properly upon standing. Normally, when a person stands, blood vessels constrict, and heart rate adjusts to maintain blood flow to the brain and vital organs. In OI, this mechanism is impaired, causing venous pooling in the lower extremities and reduced cardiac output. This leads to insufficient blood flow to the brain, resulting in Orthostatic Intolerance symptoms like dizziness, fatigue, and fainting.
Triggers and Risk Factors
Several factors can trigger or worsen symptoms of OI, including:
- Prolonged standing or sitting
- Warm environments
- Stress or emotional distress
Understanding these underlying causes and triggers is key to developing effective treatment strategies and managing symptoms day-to-day.
How Is Orthostatic Intolerance Diagnosed?
Diagnosing OI involves a combination of patient history, symptom assessment, and specialized tests to evaluate how the body responds to positional changes. Medical professionals rely on tools and diagnostic methods outlined in resources from the Bateman Horne Center to accurately identify OI subtypes and their causes.
Key diagnostic methods include:
- Tilt Table Test: Monitors heart rate and blood pressure while transitioning from lying down to an upright position.
- Active Stand Test: Evaluates heart rate and blood pressure changes after standing unaided.
- Autonomic Function Testing: Assesses the nervous system’s ability to regulate automatic functions like blood pressure and heart rate.
- Blood Volume Testing: Determines if low blood volume contributes to OI symptoms.
Accurate diagnosis is crucial for developing effective treatment and management strategies, as OI symptoms can vary widely from person to person. A healthcare provider experienced in diagnosing and treating OI can guide you through this process, offering a clearer understanding of your condition and a tailored approach to managing it.
If you suspect you might have OI, don’t hesitate to seek professional help. Specialists trained in autonomic disorders or dysautonomia can provide the expertise you need to navigate your symptoms and improve your quality of life.
OI in ME/CFS and Long COVID
OI is notably prevalent among individuals with ME/CFS and Long COVID. Research has shown that autonomic dysfunction plays a significant role in both conditions, with OI frequently presenting as a key symptom.
- In ME/CFS: Many individuals with ME/CFS experience OI, with subtypes like Postural Orthostatic Tachycardia Syndrome (POTS) and Neurally Mediated Hypotension (NMH) being common. It’s important to note that POTS is a specific type of OI, characterized by an abnormally rapid heart rate upon standing, while NMH involves a sudden drop in blood pressure. These symptoms often worsen after exertion, contributing to PEM.
- In Long COVID: Viral infections, including SARS-CoV-2, are known triggers for autonomic nervous system dysfunction, leading to OI symptoms such as dizziness, rapid heartbeat, and fatigue.
Understanding the connection between ME/CFS, Long COVID (LC), and POTS is essential for advancing research and improving treatment options for individuals affected by these overlapping conditions.
Is There a Treatment for Orthostatic Intolerance?
While there is no universal cure for OI, various management strategies can significantly alleviate symptoms and improve quality of life. For those wondering whether Orthostatic Intolerance is dangerous, it’s important to note that while the condition itself is not typically life-threatening, its symptoms can significantly impact daily life and pose risks, such as fainting-related injuries.
Treating Orthostatic Intolerance often involves a combination of lifestyle adjustments and medications, tailored to each individual’s needs and symptoms.
- Lifestyle Adjustments: Simple changes, such as staying hydrated, increasing salt intake (under medical supervision), wearing compression garments, and avoiding prolonged standing, can help manage symptoms.
- Medications: In some cases, healthcare providers may prescribe medications to address specific symptoms of OI. Common options include:
- Beta-blockers: To regulate heart rate and reduce palpitations.
- Midodrine: To help maintain blood pressure and reduce dizziness.
- Fludrocortisone: To increase blood volume and improve circulation.
Disclaimer: The information provided here is for educational purposes only and should not be considered medical advice. Always consult a qualified healthcare provider before making any changes to your treatment plan or starting new medications.
Living with Orthostatic Intolerance
Managing daily life with OI requires a proactive approach and consistent strategies. Individuals living with OI often benefit from structured routines and mindful habits to reduce symptom flare-ups.
- Hydration and Nutrition: Drinking adequate water and consuming electrolyte-rich fluids can support better blood volume and circulation.
- Environmental Awareness: Avoiding warm environments, staying cool, and minimizing prolonged standing or sitting can prevent symptom spikes.
- Supportive Gear: Compression garments for the legs and abdomen can help reduce blood pooling in the lower extremities.
For more comprehensive guidance, you can refer to the How to Manage OI resource, which provides detailed strategies for symptom management and lifestyle adaptations.
Supporting Research and Awareness for ME/CFS, Long COVID, and OI
Ongoing research into OI and its connections to ME/CFS and Long COVID is essential for advancing our understanding, improving diagnostic tools, and developing more effective treatments. Scientists and healthcare professionals are working tirelessly to uncover the underlying mechanisms of OI and identify targeted therapies that can offer relief to those affected.
At the Open Medicine Foundation Canada (OMFCA), we are deeply committed to funding groundbreaking research initiatives aimed at addressing the complexities of OI, ME/CFS, and Long COVID. Through collaborative studies and innovative projects, we strive to bring hope to millions of individuals worldwide who are navigating these challenging conditions.
Every contribution, no matter the size, plays a crucial role in advancing this research and driving meaningful change.
Join us Today:
- Support OMFCA’s Research Initiatives
- Consider supporting ongoing efforts by Donating
Together, we can build a future where individuals with OI, ME/CFS, and Long COVID receive the care, understanding, and treatments they deserve.