Vascular Headaches in Myalgic Encepahlomyelitis (ME): Blood Flow & Brain Function

Introduction

Myalgic Encephalomyelitis (ME), commonly referred to as Chronic Fatigue Syndrome (ME/CFS), is a complex, multisystem condition that affects energy production, neurological function, circulation, immune regulation and the body’s ability to respond to physical and mental demands.

Among the many symptoms experienced by people living with ME is persistent or recurring headache. For some individuals, these headaches resemble migraines, while others experience pressure, throbbing, pulsating discomfort or headaches that become worse when standing, sitting upright or engaging in everyday activities.

An area of growing scientific interest is the relationship between ME and vascular dysfunction.

The vascular system is responsible for delivering oxygen and nutrients to the brain and other tissues. When blood flow regulation, blood vessel function or autonomic nervous system activity becomes impaired, it may contribute to neurological symptoms, including headaches.

Understanding this relationship provides another perspective on why headaches can be particularly troublesome in people with ME.

1. What Are Vascular Headaches?

The term vascular headache has traditionally been used to describe headaches associated with changes in blood vessel activity, particularly those involving the blood vessels supplying the brain and surrounding structures.

Migraines were historically classified as vascular headaches because changes in blood vessel behaviour were once considered their primary cause.

Modern research has established that headaches, particularly migraines, involve more complex neurological processes. These include:

Activation of the trigeminovascular system.
Changes in sensory nerve signalling.
Release of neuropeptides such as calcitonin gene-related peptide (CGRP).
Alterations in blood vessel regulation.
Neuroinflammation and changes in pain processing.

Blood vessels and the nervous system therefore work closely together in the development of certain headache disorders.

In people with ME, vascular dysfunction is an area of ongoing investigation because abnormalities in circulation and blood flow regulation have been reported in some research studies.

Importantly, vascular headache is not a formally recognised subtype of ME. It is a useful descriptive term when discussing possible circulatory contributions to headache symptoms.

2. The Connection Between ME and Vascular Dysfunction

One of the important areas being investigated in ME is endothelial dysfunction.

The endothelium is the thin layer of cells lining the inside of blood vessels. Although extremely delicate, it performs several essential functions.

These include:

Regulating blood vessel dilation and constriction.
Controlling blood flow to different organs.
Supporting normal blood pressure regulation.
Participating in inflammatory and immune responses.
Helping maintain the integrity of the circulatory system.

Endothelial cells produce substances such as nitric oxide, which helps blood vessels relax and allows blood to flow more easily.

When endothelial function becomes impaired, the normal regulation of blood circulation may be affected.

Research has identified evidence of vascular and endothelial abnormalities in some people with ME/CFS. However, the exact mechanisms and their importance in individual symptoms are still being investigated.

Potential consequences of vascular dysfunction include altered tissue perfusion, impaired circulation and difficulties regulating blood flow in response to changing physiological demands.

These mechanisms may help explain some of the neurological symptoms reported in ME.

3. Reduced Cerebral Blood Flow

The brain requires a continuous supply of oxygen and glucose to maintain normal functioning.

Cerebral blood flow refers to the circulation of blood through the brain. The body normally regulates this circulation through a process called cerebral autoregulation.

This process allows the brain to maintain relatively stable blood flow despite changes in systemic blood pressure.

In ME, several studies have investigated whether abnormalities in cerebral blood flow contribute to symptoms such as:

Headaches.
Brain fog.
Difficulty concentrating.
Memory problems.
Dizziness.
Visual disturbances.
Cognitive fatigue.

One particularly important consideration is the possibility of reduced cerebral blood flow when a person remains upright.

This can be associated with orthostatic intolerance, a condition frequently encountered in ME.

When blood flow regulation is impaired, the brain may not receive the same level of blood supply during changes in posture as it would under normal circumstances.

Researchers continue to investigate how these circulatory changes contribute to the neurological manifestations of ME.

4. Orthostatic Intolerance and Headaches

Orthostatic intolerance (OI) refers to difficulty tolerating an upright position.

People experiencing this condition may develop symptoms when standing or sitting upright for extended periods. Symptoms often improve, although they may not disappear completely, when lying down.

Common symptoms include:

Headaches or head pressure.
Dizziness and light-headedness.
Heart palpitations.
Visual disturbances.
Weakness.
Nausea.
Difficulty concentrating.
Feeling faint.

Two conditions commonly associated with orthostatic intolerance are:

Postural Orthostatic Tachycardia Syndrome (POTS)

POTS involves an abnormal increase in heart rate when moving from a lying position to standing. It can be accompanied by dizziness, palpitations, fatigue and headaches.

Neurally Mediated Hypotension (NMH)

NMH involves an abnormal blood pressure response to remaining upright. Blood pressure may drop, potentially reducing blood flow to the brain and contributing to dizziness, weakness and headache.

Not everyone with ME experiences POTS or NMH, and these conditions can also occur independently of ME.

Recognising orthostatic intolerance is important because a headache that becomes worse when upright may have a different underlying mechanism from a typical migraine.

5. The Trigeminovascular System and Migraine-Like Headaches

Another important connection involves the trigeminovascular system.

This system consists of sensory nerve pathways associated with the trigeminal nerve and the blood vessels surrounding the brain.

The trigeminal nerve is responsible for carrying sensory information from much of the face, forehead and head.

When trigeminovascular pathways become activated, they can contribute to headache pain.

One important chemical messenger involved in migraine is Calcitonin Gene-Related Peptide (CGRP).

CGRP is a neuropeptide that participates in pain transmission and influences blood vessel activity. During migraine attacks, CGRP signalling can contribute to the development and maintenance of pain.

Migraine-like headaches may therefore involve several overlapping processes:

Increased sensitivity of sensory nerve pathways.
Altered vascular signalling.
Activation of inflammatory mediators.
Changes in pain-processing networks.
Increased sensitivity to light, sound and other environmental stimuli.

People with ME may experience headaches alongside heightened sensory sensitivity, making ordinary environmental stimulation particularly uncomfortable.

However, ME does not automatically cause migraine, and migraine should be assessed as a potentially co-existing condition.

6. Autonomic Nervous System Dysfunction

The autonomic nervous system regulates many functions that happen automatically, including:

Heart rate.
Blood pressure.
Blood vessel diameter.
Digestion.
Sweating.
Body temperature.
Circulatory responses to posture.

The sympathetic and parasympathetic branches work together to maintain physiological balance.

In ME, autonomic dysfunction is an important area of research.

When autonomic regulation is impaired, the body may struggle to adjust circulation appropriately when moving between lying, sitting and standing positions.

This may contribute to:

Abnormal heart rate responses.
Blood pressure fluctuations.
Reduced tolerance for prolonged standing.
Changes in peripheral circulation.
Dizziness and headaches.

Autonomic dysfunction may also interact with other physiological processes, including sleep regulation, stress responses and sensory processing.

This helps explain why symptoms in ME can affect several seemingly unrelated body systems simultaneously.

7. Inflammation, Vascular Signalling and Blood Vessel Regulation

Inflammation and vascular regulation are closely interconnected.

Inflammatory mediators can influence blood vessel behaviour, endothelial function and the communication between blood vessels and surrounding tissues.

Some researchers have proposed that abnormal inflammatory and vasoactive signalling may contribute to the complex symptoms experienced in ME.

Vasoactive substances are chemicals that influence the diameter and activity of blood vessels.

Examples include:

Nitric oxide.
Prostaglandins.
Histamine.
Bradykinin.
Calcitonin gene-related peptide (CGRP).

These substances participate in various physiological processes, including vascular regulation, immune responses and pain signalling.

An imbalance in these pathways could potentially influence headache development in susceptible individuals.

However, there is currently no single established inflammatory or vascular mechanism that explains all headaches associated with ME.

8. Recognising Different Headache Patterns in ME

Not every headache experienced by someone with ME has the same underlying cause.

Understanding the characteristics of a headache can help guide further investigation.

Migraine-like headaches

These may involve throbbing or pulsating pain, nausea, light sensitivity, sound sensitivity and worsening discomfort with movement.

Orthostatic headaches

These become worse when sitting or standing upright and may improve when lying down. They can occur alongside other symptoms of orthostatic intolerance.

Tension-type headaches

These often produce a pressing or tightening sensation, sometimes described as a band around the head. Neck and shoulder muscle tension may contribute.

Cervicogenic headaches

These originate from structures in the neck and may produce pain that radiates towards the back of the head, temples or forehead.

Post-exertional headaches

Some individuals experience worsening headaches following physical, cognitive or emotional exertion. This may occur as part of post-exertional malaise (PEM), the characteristic worsening of ME symptoms following activity.

Different headache types can overlap, making proper assessment important.

9. Why Post-Exertional Malaise May Make Headaches Worse

Post-exertional malaise is one of the defining characteristics of ME.

It refers to a worsening of symptoms following activity that would previously have been manageable.

The worsening may be delayed, sometimes becoming noticeable many hours or even a day or two after the activity.

For some people, PEM includes:

Increased head pressure.
More frequent headaches.
Greater sensitivity to light and sound.
Increased brain fog.
Dizziness.
Muscle pain.
Sleep disturbances.

The mechanisms behind PEM are not fully understood.

Research is investigating several possible contributing processes, including impaired energy metabolism, immune signalling, autonomic dysfunction and abnormalities in circulation.

The relationship between these mechanisms and headache aggravation remains an important area for further research.

10. Supporting Circulatory and Neurological Wellbeing

There is currently no single treatment that corrects all the possible vascular and neurological abnormalities associated with ME.

Management should be individualised and guided by a healthcare professional familiar with the condition.

Some approaches that may help manage symptoms include:

Pacing and energy management

Learning to recognise personal energy limits and avoiding repeated overexertion can help reduce the risk of post-exertional malaise.

Pacing does not mean following a fixed exercise programme. Activity should be adjusted according to individual tolerance.

Managing orthostatic intolerance

People experiencing symptoms when upright may benefit from discussing orthostatic intolerance with a healthcare professional.

Depending on the individual, management may involve reviewing fluid intake, salt intake, compression garments and medication. These interventions should be tailored to the person’s medical circumstances.

Hydration

Maintaining appropriate hydration supports normal circulatory function. Individuals with heart, kidney or other medical conditions may need specific fluid recommendations.

Sleep support

Sleep disturbances can worsen headache sensitivity, pain perception and cognitive difficulties. Addressing sleep-related problems may improve overall symptom management.

Identifying co-existing headache disorders

Migraine, tension-type headaches, temporomandibular joint disorders and cervical problems can coexist with ME.

Identifying these conditions is important because they may require their own treatment approaches.

11. Exploring the Relationship Between Circulation, Energy and the Nervous System

ME highlights how closely connected the body’s systems really are.

The circulatory system supplies the brain with oxygen and nutrients. The nervous system regulates blood vessel activity. The immune system communicates with vascular tissues, while metabolic processes provide the energy needed to maintain normal cellular function.

When several of these systems are affected simultaneously, symptoms can become complex and difficult to interpret.

From a whole-person wellbeing perspective, it is useful to explore how different physiological systems interact rather than looking at headaches as an isolated complaint.

This includes considering:

Cardiovascular and circulatory function.
Nervous system regulation.
Immune and inflammatory signalling.
Cellular energy metabolism.
Sleep and recovery.
Musculoskeletal tension.
Sensory processing.

This broader perspective does not replace medical assessment or establish a diagnosis. Instead, it encourages a more comprehensive understanding of the factors that may influence an individual’s wellbeing.

12. When Should a Headache Be Medically Evaluated?

People with ME should not automatically assume that every new headache is part of their existing condition.

A sudden, extremely severe headache, a new headache accompanied by weakness, numbness, difficulty speaking, confusion, seizures, loss of vision or significant balance problems requires emergency medical assessment.

A headache associated with fever, neck stiffness or a new neurological symptom also needs urgent assessment.

Persistent, progressively worsening or substantially changing headaches should be evaluated by a healthcare professional.

New headaches that are consistently worse when upright, particularly when they improve significantly after lying down, also deserve medical investigation.

These symptoms can sometimes indicate conditions other than ME-related orthostatic intolerance.

Conclusion

Vascular dysfunction, altered cerebral blood flow and autonomic nervous system abnormalities represent important areas of scientific investigation in Myalgic Encephalomyelitis.

Although the exact relationship between these mechanisms and headache development is not yet fully understood, research suggests that circulatory regulation and neurological signalling may contribute to the complex symptoms experienced by some individuals.

Understanding the relationship between the vascular system, brain function and autonomic regulation may help us better appreciate why headaches in ME can be persistent, unpredictable and particularly debilitating.

The key is to recognise that headaches are not necessarily an isolated problem. They may reflect interactions between several physiological systems, each contributing to an individual’s overall symptom experience.

Understanding the connections is an important step towards better-informed, more comprehensive wellbeing support.

References and Further Reading

Wirth, K. J., et al. (2021). An attempt to explain the neurological symptoms of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Journal of Translational Medicine. https://doi.org/10.1186/s12967-021-03143-3
Wirth, K. J., et al. (2023). Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Comorbidities: Linked by Vascular Pathomechanisms and Vasoactive Mediators? https://pmc.ncbi.nlm.nih.gov/articles/PMC10224216/
Centers for Disease Control and Prevention (CDC). Clinical Overview of ME/CFS. https://www.cdc.gov/me-cfs/hcp/clinical-overview/
National Institute for Health and Care Excellence (NICE). Myalgic encephalomyelitis (or encephalopathy)/chronic fatigue syndrome: diagnosis and management (NG206). https://www.nice.org.uk/guidance/ng206
National Institute of Neurological Disorders and Stroke (NINDS). Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. https://www.ninds.nih.gov/health-information/disorders/mecfs-myalgic-encephalomyelitischronic-fatigue-syndrome

Medical Disclaimer: This article is intended for educational and general wellbeing information only. It does not constitute medical advice, diagnosis or treatment. ME/CFS is a complex medical condition requiring appropriate professional assessment. The vascular mechanisms discussed are areas of ongoing scientific research and should not be interpreted as established explanations for every person’s symptoms.