Friday 22 March 2024

'First Aid' for M.E. Energy Systems - Heart Rate Monitoring


Heart Rate Monitoring to Manage Limited Energy Reserves & Avoid Post Exertional Response (PENE)

Heart rate is a common cardiovascular parameter measured by commercially available biometric devices, i.e., Heart Rate Monitors, which are useful tools to help people with ME maintain activities at intensities below ventilatory anaerobic threshold (VAT) and prevent the abnormal post exertion response which occurs in ME (PENE).

Heart Rate Monitoring (HRM) during activity can be a strategy that provides useful feedback that promotes symptom awareness and control. When a higher than usual heart rate is associated with symptoms and perceived exertion it becomes a very affective tool to manage the abnormal post exertion response in ME, i.e., Post Exertional Neuro-immune Exhaustion (PENE).

Workwell Foundation's Heart Rate Monitoring Factsheet

Workwell Foundation’s 2023 Webinar about Energy Management & Heart Monitoring

Two Problematic Features in ME are PENE and Energy

(1) PENE

The abnormal post exertion response in Myalgic Encephalomyelitis (ME) known as Post Exertional Neuro Immune Exhaustion (PENE), also referred to as PEM, includes a marked physical and or mental deterioration in response to increased activity, muscle and joint pain, cognitive dysfunction and extreme fatigue. Even light or easy everyday tasks can exacerbate PENE, cause dizziness and other horrendous symptoms and prolong recovery time. PENE can also be triggered by mental exertion, stress, sleep deprivation and infection. (see scientific piece about PENE further below and a link to our webpage about PENE)

It is very important to try and avoid PENE if possible as it is believed to potentially set back recovery. The exhaustion felt may be immediate after the activity/exercise or may be delayed by hours or days. Recovery normally takes 24 hours or longer and often people find that their heart rate is higher than normal during ‘everyday tasks’.

(2) Energy

Energy production is not normal in ME; the ability of energy reaching cells is damaged in ME. Keeping within ones’ energy envelope is a management strategy in ME. The energy envelope technique for managing and preventing symptoms is a way of describing the amount of energy a person with ME has available each day and how they best use that energy supply. Energy Envelope energy is energy that you can safely use without triggering relapse. How much energy you have will depends on how badly ME affects you. It can also change from day to day, which means that an activity that you managed yesterday may exhaust you today.

Many people with ME use a Heart Rate monitor as an ME management strategy, i.e., as an energy management strategy to pace their daily activity and monitor their body’s responses to physical exertion more accurately. Although there are limitations, Heart Rate Monitoring has many benefits including helping people with ME to understand and manage their PENE (also referred to as PEM) and to stay within an energy envelope.

Avoiding PENE is Key to Management in ME

Post Exertional Neuroimmune Exhaustion - PENE is the cardinal feature of ME according to the International Consensus Criteria and Primer on ME. There is a long list of atypical symptoms that occur when a person with ME suffers from Post Exertional Neuro-Immune Exhaustion - PENE; marked debilitating illness and weakness, cognitive dysfunction, symptom flare-up and possible paralysis as seen in severe ME, can follow ANY physical or cognitive exertion requiring energy, no matter how small or insignificant the exertion. 

Essentially what it means is that any exertion, physical, cognitive or even emotional stress creates a prolonged reaction in the body where a relapse or worsening of these ME symptoms occur and can last for days, weeks, months or longer. 
Indeed, many people who have pushed far too hard beyond their limits have become bedbound and carer dependent for years.

Worsening symptoms in ME as a result of Post Exertional Neuroimmune Exhaustion -PENE may include exhaustion, extreme chronic pain, paralysis, brain fog, cognitive dysfunction, unrefreshing sleep, headaches, migraines, muscle pain and muscle fatigability, orthostatic intolerance, neurally mediated hypotension, or POTS, inability to eat, swallow or digest food, and much more. 

Another distinctive element of Post Exertional Neuroimmune Exhaustion - PENE is often described as a loss of stamina and/or functional capacity.

There are some strategies people with ME can use to avoid PENE and to manage other symptoms; they include:
    • Exercise intolerance avoidance management strategies such as pacing and resting 
    • Symptom management to reduce symptom burden & increase QOL 
    • Receiving validation and reassurance that your symptoms are due to a biological issue across various body systems 
    • Accessing supports such as Community Services & Welfare payments 
    • Staying within your energy envelope
    • Learning your illness patterns
    • Building your support community e.g., family, carers, doctors, specialists
    • Ensuring good nutrition
    • Ensuring appropriate sleep
    • Maintaining emotional health
    • Avoiding stress
    • Treating other medical conditions

Important Note about Very Severe ME
People with Severe ME spend days struggling to cope from moment to moment in the most awful suffering. For those, and others with ME, pacing may not be an option to manage ME because the body can be in such turmoil that patients can't pace enough to impact disease processes, for example, someone who has severe/very severe or profound ME who lies completely still because any movement at all can cause awful debilitating symptoms. 
For those patients no amount of pacing can help if digesting food requires more energy than the body can produce; no amount of pacing can help when trying to keep warm; no amount of pacing can help when the person has multiple sensitivities and is already responding negatively to light or sound or movement.


Using a Heart Rate Monitor

There are as yet no defined protocols for heart rate monitoring and people with ME are using different methods.

Using a heart rate monitor, to measure heart rate, heart rate variability, and other factors, allows people with ME to observe their energy usage, and learn how to stay within their safe limits. This pacing method is often used in conjunction with other treatments e.g., extreme resting.
Anecdotally, some people experience gradual improvements in their health when using a heart rate monitor.

Workwell Foundation Logo

Using a Heart Rate Monitor - the Workwell Foundation 

An energy management strategy incorporating heart rate monitoring (HRM), first developed by the Workwell Foundation in 2010, has been incorporated into a number of consensus and guidance documents, and is considered a reliably effective intervention among people with ME. This energy management strategy suggests identifying the average resting heart rate over seven days and then setting a limit of 15 beats above that resting heart rate (HR) using HRM to reduce activity above that limit. Please see Workwell Foundation's Heart Rate Monitoring factsheet below for more details.

Workwell Foundation's Heart Rate Monitoring Factsheet

Heart rate monitoring during activity provides biofeedback that promotes symptom awareness and control.
When heart rate is associated with symptoms and perceived exertion, it becomes a powerful tool to manage the abnormal post- exertional response in ME i.e., post exertional neuro immune exhaustion (PENE), a worsening of symptoms after activity. 

Activity in ME could refer to the most basic demands on the body like thinking or seeing or could refer to more strenuous activity such as eating or walking to a different room. Activity could simply be moving in bed after waking up or standing up or sitting up. 

Link to Workwell Foundation’s Heart Monitoring Factsheet: 

Workwell Foundation’s 2023 Webinar about Managing Limited Energy and Avoiding PENE by Heart Rate Monitoring 

Another excellent resource about activity management and heart rate monitoring is the Workwell Foundation's 2023 webinar (1 hr long incl 45 min presentation & Q&A) entitled 'Heart Rate Biofeedback for Myalgic Encephalomyelitis: From Physiology to Practice'.

During the webinar Mark Van Ness and Todd Davenport discuss PENE, the idea of identifying PENE symptoms, using heart rate monitoring to delimit activity and to avoid PENE.
They also mention different types of heart rate monitors and describe particular case studies.

The video of the webinar held last tear includes information on monitoring heart rate and using a heart rate monitor to limit the post exertional response in ME, i.e., PENE (also referred to as PEM). Please see the video linked below:

Information from others re Heart Rate Monitoring (HRM) 

  • Heart Rate (HR) & Post-Exertional Crashes in ME, see Suzan Jackson’s most popular blog posts which explains how HR relates to exertion intolerance, how to use a HR monitor to prevent crashes, how to improve stamina, and choosing a HR monitor here

  • Heart Rate monitoring from Sally Burch in her blog "Just ME" here

  • Tips on using a HR Monitor from Caroline Christian (US) here

  • Heart Rate Monitoring by Physios for ME (UK) here

  • HR Monitor Facebook Group here

More about Post Exertional Neuroimmune Exhaustion (PENE)

To understand how heart rate monitoring works it is important to understand PENE (also referred to as PEM)

One area of research using cardiopulmonary exercise testing (CPET) has shown that people with ME have a reduced ventilatory anaerobic threshold (VAT) especially when the test is repeated on a second consecutive day.

CPET Testing 

To show what is happening in ME the Workwell Foundation developed the 2-day Cardiopulmonary Exercise Testing (CPET) that measures AT and shows clearly that PENE results after exertion, further dropping AT on the second day. 
This is the most accurate way to measure your AT and the best test to use in a disability case because it provides evidence of PENE, however, not all ME patients are able to do this test; it would be harmful to many with ME especially people with severe ME. For those patients recordings of heart rate monitoring using heart rate monitors would be useful evidence of PENE.

The VAT or lactate threshold is the point at which a person switches from aerobic to anaerobic metabolism, and there is an increased production of lactate as a by-product. People with ME have been shown to reach this threshold more quickly than healthy people, and it is theorised that this could be due to inefficient and damaged aerobic metabolic processes causing PENE.

The early production of lactate during activity or inefficient production of adenosine triphosphate (ATP) could explain the symptoms of PENE such as muscle and joint pain, cognitive dysfunction and extreme fatigue in ME. In addition, decreased oxygen extraction in a subset of ME patients suggests ME involves a problem of oxygen utilization rather than bioavailability. This phenomenon may be responsible for observed maladaptation in autonomic function, including orthostatic and chronotropic intolerances.

It follows from findings of physiological studies that pacing activity intensities and durations may help people with ME to stabilize symptoms and functioning.

Important Note about Very Severe ME

It is important to realise that at the severe end of the spectrum people with Severe ME don’t need to exert themselves for the phenomenon PENE to operate, there can be a critical response to the slightest movement by the patient or by the movement of a visitor to the patient's bedroom. Even simple brain activity can lead to worsening of illness in ME, e.g., hearing noise from outside the bedroom.
For very severely affected ME sufferers there is virtually no ‘safe’ level of physical or mental activity, orthostatic stress or sensory input; no level which does not produce a worsening of symptoms, and perhaps also contribute to disease progression.

Further Reading

  • More about PENE here

  • Other Management Strategies in ME 
There is currently no cure for Myalgic Encephalomyelitis (ME), and no universal treatments available, however, there are some excellent strategies that healthcare professionals and patients can use to manage symptoms and symptom severities. 
Early management following illness onset may reduce the risk of further disability and the patient's condition deteriorating.
Heart rate monitoring was discussed above, see other Management Strategies here.

Thanks to Mark Van Ness, Todd Davenport and others at the Workwell Foundation for your invaluable work on behalf of people with M.E.

Disclaimer: The information in this post is for general information purposes only. While we endeavour to keep the information up to date and correct, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the post or the information, products, services, etc contained in the post for any purpose. Any reliance you place on such information is therefore strictly at your own risk.The suitability of any solution is totally dependent on the individual. It is strongly recommended to seek professional advice and assistance. 

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