I watched this whole presentation. Nothing in it was totally new, but I liked it. It was a solid overview of PEM and useful for educating doctors and PTs. Dr. Davenport is insightful and empathetic. Repeatedly, he emphasized that PEM and deconditioning have both entirely different causes and effects. For example, exercise should not cause cognitive dysfunction.
He reviewed a graph of symptoms people experience at 6:31, emphasizing that the symptoms pwME experienced were vastly worse than the sedentary controls.
Around 14:51, he colors his explanation with quotes from pwME. "[Felt] like I was in a barrel and rolled down hill!" was the funniest.
At 16:30, he discusses LC symptoms and how PEM is very common.
Around 20:00, he uses a slide from Workwell to explain that he thinks the short-term PEM symptoms are more neurological, and the longer-term ones more physical.
At 23:27, he explains the criteria for evaluating maximum effort in the CPETs, emphasizing they use respiratory exchange ratio: "Probably the criteria we put the most stock in is this RER because
you can't fake that. There's no faking it." Then describes how people with all sorts of other conditions can reproduce their performance, but pwME can't.
Around 27:40, he discusses the body's different energy sources, and how aerobic metabolism is impaired in ME. He goes into how the anaerobic threshold drops on the second day, and speculates acidosis could contribute to some ME symptoms. At 33:20, he says that exercise tests correctly classify 90% of controls and 95% of pwME. He sees the 2-day CPET as a biomarker:
And if we just looked at VO2 and workload at that breakpoint (that breakpoint between aerobic and anaerobic metabolism), we can correctly classify 95% of patients with CFS and 90% of matched sedentary control subjects. So here we talk about "no biomarkers," "we need a biomarker," acknowledging the significant challenges and issues associated with cardiopulmonary exercise testing, this seems like the closest biomarker we may have in order to characterize patients.
He summarizes all this at 33:58, and provides an analogy of a plug-in hybrid car.
Then he describes screening for PEM, and management. First, you pace. Once you're good at pacing, exercise may help, but he makes it amply clear that patients must stay within their energy envelope--"exercise to the exclusion of activities of daily living is not restorative." He later clarifies that what he calls "exercise" is very light.
At 43:44, he discusses "Moving beyond energy system first aid." Unfortunately, there's not much you can do, especially with direct treatments. He says POTS palpitations should be ignored for heart-rate based pacing, which seems fishy to me. (Maybe he means, only if they're brief?)
They conclude with Q&A at 44:47:
Could PEM be related to the cardiovascular risks of Covid? He seems to lean towards no.
A woman with fibromyalgia says the presentation may have given her some insights about her symptoms.
How does pacing allow you to tolerate exercise and how does it compare to reversing deconditioning? Deconditioned people don't need to pace. In ME or LC, the body's response is entirely different. Unfortunately, we don't know why. Mentions a pwME whose exercise test results improved after resting more (!) Maybe ME is vaguely similar to overtraining.
Could PEM in LC be related to viruses hijacking mitochondria? Maybe if viral persistance is true. Mentions upcoming metabolomics studies of ME/CFS.
Are you investigating NF-kB pathway in LC? It might be involved.
Do you do heart rate with monitors with exercise therapy? Yes. "Exercise doesn't look much like exercise. It looks very light. We're doing stretching and breathing...and that's enough exercise for people" The vast majority of his time is spent on pacing and energy conservation.
Someone is wondering why exercise helps her back pain. He says it's better for a group discussion.
