Estimating thresholds without CPET

Why can exercise cause post-exertional malaise (PEM) in complex chronic illnesses like ME/CFS and Long Covid, and how do we avoid the crashes?

If you experience a crash after a period of exertion, if traditional methods of ‘increasing fitness’ actually leave you with terrible side effects, this podcast is for you.

In this episode of Make Visible, physiotherapist and exercise scientist Todd Davenport joins Emily Kate Stephens to delve into the complex relationship between exercise, energy systems, and PEM in conditions like ME/CFS and Long Covid.

Davenport explains why traditional exercise approaches can actually be harmful for people with PEM, which he prefers to term post-exertional symptom exacerbation (PESE) or post-exertional neuroimmune exhaustion (PENE) to more accurately describe this hallmark symptom.  He discusses how tools like the two-day cardiopulmonary exercise test (CPET) show impairments in oxygen use and energy production, and he talks us through how keeping the body below “ventilatory anaerobic threshold” using heart rate monitoring, pacing, and individualized activity management can slowly improve symptom burden and baseline – without triggering crashes.

This conversation challenges long-held assumptions about deconditioning and offers a nuanced, physiology-informed, individualized approach to care, that patients can manage themselves.

Topics include:

• Why exercise can worsen symptoms in ME/CFS and Long Covid
• What two-day CPET reveals about oxygen use and metabolism
• Is it post-exertional malaise or deconditioning?
• Using heart rate monitors for pacing
• Differences between ME/CFS, Long Covid, and POTS

And Emily Kate is once again joined by Gez Medinger to break down the ideas presented by this week’s guest, relating it to their own experiences of living with energy limiting conditions.

Todd Davenport is Professor and Chair of the Doctor of Physical Therapy (DPT) Program at University of the Pacific.  His clinical and academic interests as a physical therapist and exercise scientist revolve around complex chronic conditions (commonly preceded by an infection) such as ME / CFS (myalgic encephalomyelitis) chronic fatigue syndromes and Long Covid, working to understand the systems-level pathophysiology of post-exertional malaise /post-exertional neuroimmune exhaustion.

Explainers:

Anaerobic Ventilatory Threshold

CPET testing

Oxidative phosphorylation

Mitochondrial Impairment

Neuroimmune Exhaustion

You can find guidelines for pacing with a heart rate monitor to minimize PEM in ME/CFS and Long Covid here.

Further reading / referenced studies:

ME/CFS and Long COVID Demonstrate Similar Bioenergetic Impairment and Recovery Failure on Two-Day CPET (pre-print)

Physical therapy management of POTS using a pacing approach: a case report

Cardiopulmonary responses to exercise in ME/CFS: A case study

Altered effort and deconditioning are not valid explanations of ME/CFS

Make Visible

@visible_health

@visible.health