Physical Exertion in ME & the PEM/PESE effect, with Karen Leslie of Physios for ME


Rob Messenger shared his motivations for raising funds and awareness for ME by walking 500 miles over 100 days and climbing a total of 65,000 feet in 2 previous blog posts: Fundraising success and Awareness raising. Now he shares reflections of his Discussions at Dawn videos

We recently bought another 4 more copies of A Physiotherapist’s Guide to Understanding and Managing ME/CFS, which was published in August last year, just a month or so after my Discussion at Dawn with one of its authors, Karen Leslie of Physios for ME.

Why 4? Well, it’s a great book about ME – aimed primarily at physios, but so well researched, up to date  and clearly written, that if you want to raise the understanding of any of the professionals working with you, or even your friends or family members, this book does the job.

So we’ve been saving up and buying them to give away – so far to: our Health Board’s Exec member for Neurology and Therapies (she invited me in to meet her), the HB officer setting up the new extended Long Covid + service (includes ME), a neuro rehab consultant , a registrar, and our GP. These four books are for the physio and OT from the neuro team, and a psychologist, and A.N.Other. Can’t recommend the book highly enough.

Not just about physical energy

I guessed that people who’ve heard just a bit about ME might associate it mainly with ‘fatigue’, and would think that’s to do with not having enough physical energy. Actually, ME is a multi-system illness producing multi-symptoms, and the ‘fatigue’ bit of it is both well beyond the kind that most of us experience, and can be both physical and neuro-cognitive.

Anyway, I thought I should check out the physical side of things first. What’s the latest science?

I guessed Physios for ME would know about that, and Karen Leslie kindly agreed to help me understand why an old bloke like me can hike 5 miles, puffing and panting his way up to Paxton’s Tower every morning, but our son who has very severe ME can’t even stand up, let alone walk out of his room.

Even after editing, the video of our discussion was >50 minutes long!  Well, there was a lot to talk about. And it’s really worth a listen – get yourself a cuppa and do it.

Physios for ME

Discussions at dawn interview with Karen Leslie

Karen explained that Physios for ME (there are 4 of them: Dr Nicola Clague-Baker, Dr Michelle Bull, Natalie Hilliard, and Karen) got together out of a shared professional experience of working with people with ME, and/or personal experience of being close to someone with the diagnosis.

We agreed that, in our experience, something that stands out in people with ME is their amazing psychological resilience in the face of adversity, and their desire and determination to try and get better.

Physios for ME are all very experienced professionals with different specialisms. As a specialist neurological physiotherapist , Karen works with people with many complex conditions, including stoke, brain injuries, MS and Parkinsons. She said:

“I treat lots and lots of really complex conditions, and wherever I go I know that my physio toolkit will help these people, and I can make a big difference. And I was pretty confident in that until I met somebody who had severe ME”.

She realised that lack of training and awareness means that she and her fellow physios in general have been poorly prepared to meet the needs of people with ME.

The PEM/PESE effect

The difference with ME is the need to consider post-exertional malaise  (PEM) – when multi-symptoms can be worsened and persist in a way which is out of all proportion to minimal ‘exertion’. It’s the stand-out feature of ME, but it’s poorly understood by health professionals.

Karen told me that sports scientists at the Workwell Foundation have used repeat Cardio-Pulmonary Exercise Tests (CPETs) to measure the difference between ME patients and healthy people, and to find a way of objectively measuring  PEM. They found that the ME patients started working anaerobically (rather than aerobically) much sooner than the healthy participants.

These were patients whose ME was towards the ‘milder’ end of the severity spectrum (they couldn’t have taken part if they were ‘severe’), but even so, whereas the healthy ‘control group’ could do just as well on the second day as the first, the average recovery time for the ME patients was 2 weeks, and one had not recovered a year later.

The PEM effect is disabling, and multi-system, which is why some prefer the term post-exertional symptom exacerbation (PESE). Although the trigger, in this experiment, is physical exertion, the effect is not just physical ‘fatigue’, but also body pain, and neuro-cognitive-sensory symptoms, affecting the ability to think and communicate, or deal with light and sound, for example.

We also discussed the apparently bizarre PEM effect my daughter experiences – getting pain in her legs when trying to read – and learned that this was neither unique nor inexplicable.

Cognitive ‘exertion’, or exposure to sensory overload, can also cause an exacerbation of both neuro-cognitive-sensory and physical symptoms.

Karen explained that Physios for ME have encountered this phenomenon in their ‘feasibility study’, in which people with severe ME  were visited at home and observed / measured when doing simple activities of daily living. Their observations were in line with Workwell’s results, but with more severe patients.

Unexpectedly, it was during a cognitive Maths challenge that the most people began working anaerobically, leading to physical symptoms including body pain.

PEM can only be relieved over time, with rest. But, if pushed too far, the person can be tipped into a longer lasting, more severe phase of the illness. This is why physiotherapists have to be aware of what’s happening physiologically in the ME patient, and take care not to trigger PEM.

“But that’s my job –  to adapt how I’m working to make sure that I’m not causing that person any harm”, Karen said.

Alternatives to Graded Exercise Therapy

We talked about how physiotherapists have to find strategies other than Graded Exercise Therapy (GET), since NICE (National Institute for Clinical and Health Excellence) concluded in its 2021 revised guidance, that:

“…any programme using fixed incremental increases in physical activity or exercise (for example, graded exercise therapy), or physical activity or exercise programmes that are based on deconditioning and exercise avoidance theories, should not be offered to people with ME/CFS. The committee also wanted to reinforce that there is no therapy based on physical activity or exercise that is effective as a cure for ME/CFS.” (NG206 p78)

Karen gave lots of examples of how physiotherapists can assist people with ME, including helping them to understand energy management techniques – e.g. using pacing, and the value of ‘wearable devices’ and appropriate equipment.

She talked about the need for physiotherapists to be aware of the risk of PEM in ME patients, so that when exercise is appropriate or necessary, it can be used safely e.g. when the ME patient needs physiotherapy following an injury.

Info for physios

[N.B. And Physios for ME have recently published a one page leaflet to for people in that situation – a brief guide to give to your physiotherapist. Find it here in English and Welsh (and other languages).]

We went on to discuss Long Covid, and Physios for ME’s ambitions for research, and, of course, the book, which at that time was just being prepared for publication.

You can get it from the publisher: here as well as from bookshops and other on-line booksellers.

Catch up with Physios for ME’s resources, latest news and research at

BIG THANKS!  to Karen for agreeing to have a Discussion at Dawn with me, and for all she and Physios for ME are doing to try to make the sun rise for people with ME!   Watch the video

 Rob’s interview with Dr Nina Muirhead

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