Exercise does not cause post-exertional malaise Gulf War Illness: A randomized, controlled, dose–response, crossover study, 2024, Boruch et al.

Exercise does not cause post-exertional malaise in Veterans with Gulf War Illness: A randomized, controlled, dose–response, crossover study
Boruch; Barhorst; Rayne; Roberge; Brukardt; Leitel; Coe; Fleshner; Falvo; Cook; Lindheimer

ABSTRACT
Chronic multisymptom illnesses (CMI) such as Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, long-COVID, and Gulf War Illness (GWI) are associated with an elevated risk of postexertional malaise (PEM), an acute exacerbation of symptoms and other related outcomes following exercise. These individuals may benefit from personalized exercise prescriptions which prioritize risk minimization, necessitating a better understanding of dose-response effects of exercise intensity on PEM.

METHODS
Veterans with GWI (n=40) completed a randomized controlled crossover experiment comparing 20 minutes of seated rest to light-, moderate-, and vigorous-intensity cycling conditions over four separate study visits. Symptoms, pain sensitivity, cognitive performance, inflammatory markers (C-reactive protein and plasma cytokines) were measured before and within 1 hour after exercise and seated rest. Physical activity behavior was measured ≥7 days following each study visit via actigraphy. Linear mixed effects regression models tested the central hypothesis that higher intensity exercise would elicit greater exacerbation of negative outcomes, as indicated by a significant condition-by-time interaction for symptom, pain sensitivity, cognitive performance, and inflammatory marker models and a significant main effect of condition for physical activity models.

RESULTS
Significant condition-by-time interactions were not observed for primary or secondary measures of symptoms, pain sensitivity, cognitive performance, and a majority of inflammatory markers. Similarly, a significant effect of condition was not observed for primary or secondary measures of physical activity.

CONCLUSIONS
Undesirable effects such as symptom exacerbation were observed for some participants, but the group-level risk of PEM following light-, moderate-, or vigorous-intensity exercise was no greater than seated rest. These findings challenge several prior views about PEM and lend support to a broader body of literature showing that the benefits of exercise outweigh the risks.

Link | Paywall (Brain, Behavior, and Immunity)

 

What was the point? Are they trying to show that not all people with gulf war illness have PEM?

What does this mean:

So some people in the study had PEM, but if you take the results of the group on average, then the average person in the group didn't? Is that was "group-level risk" means?

Link to PDF doesn't work, by the way.

 

Paywall - corrected.

 

Supplemental Fig S7. Individually reported changes in Kansas fatigue scores before and 10-min after exercise and seated rest

 

Did they only test symptoms within one hour after exertion? So they missed any PEM that takes longer than one hour to appear?

@SNT Gatchaman Do you have the charts or any text about the "physical activity behavior"?

 

In the methods on at-home measures (i.e. the 7 days following), they write —

The results subsection for physical activity states (in total) —

 

Hmm, if they already spend 10% of their waking hours (~1.6 hours) doing "moderate-vigorous activity", it's not surprising that the exercise test wasn't very bad for them.

 

Also group mean of ~6700 steps/day and 58 sit-to-stand transitions/day.

 

Symptom criteria

From the Kansas GWI paper (Steele 2000) research criteria Prevalence and patterns of Gulf War illness in Kansas veterans: association of symptoms with characteristics of person, place, and time of military service - PubMed (nih.gov) which is referred in the 2024 study:

Recent research on Gulf War illness and other health problems in veterans of the 1991 Gulf War: Effects of toxicant exposures during deployment - PMC (nih.gov) 2016

This paper also reports higher prevalence of light sensitivity and skin problems.

Contrast and compare with this paper, and note the letters to the editor on publication of the paper.

Chaudhuri A, Behan WMH, Behan PO. Chronic Fatigue Syndrome. Journal of the Royal College of Physicians of Edinburgh. 1998;28(2):150-163. doi:10.1177/147827159802800203

Chronic Fatigue Syndrome - A. Chaudhuri, Wilhelmina M.H. Behan, P.O. Behan, 1998 (sagepub.com)

Chronic Fatigue Syndrome | Royal College of Physicians of Edinburgh (rcpe.ac.uk) pdf



Vol28_4.1.1 (rcpe.ac.uk) letters in response to research by Chaudhuri, Behan and Behan 1998 from Reilly, Wessely and Hotopf and Chaudhuri and Behan's response.

 

So, one of the latest trends is clearly to argue that people who may or may not report PEM don't show PEM according to them. This are several studies doing the same bit.

"Views" such as widespread reports of PEM, which not everyone with GWI has, and this cohort was clearly highly active so would be unlikely to have PEM anyway. And what benefits of exercise? No benefits have been shown from exercise to people with chronic illness, or at best trivial. It's always generic benefits, but they're always said to improve symptoms.

This is obviously not a serious way of researching this. If you take a random group of people who mostly don't have allergies, if you take a group-level average and ignore the allergic reactions, this group doesn't appear to have significant problems with allergies.

Decade after decade of wasted lives. Eventually all GWI veterans will be dead, so the problem will have taken care of itself. Nevermind the lives of the patients, they clearly don't matter.

It's so hard to accept that my life is ruined by this mediocrity. I am furious with this bullshit.

 

The strange thing is that it seems that all these authors (pretty much) are students or very junior. Some involved in psychology, some sport.

Some of them have an interest in ME/CFS/. Maybe somebody hoped they could show GWI people had PEM. But why say exercise benefits outweigh risks?

It's like some sort of AI product. Barmy.

 

I wonder what the point is of labelling someone who can walk 6700 steps, with GWI. GWI should be about disability, and I don't see disability with someone who can take 6700 steps on average. Not a physical disability, anyway. The paper studied the non-disabled and then extrapolated the result to the disabled, it appears.

 

"The paper studied the non-disabled and then extrapolated the result to the disabled" would be more accurate as "The paper studied people people diagnosed with GWI who walk a lot and extrapolated to people with GWI who do not/can not walk a lot."

Disability can come in a million different forms. Being able to walk a lot doesn't mean you aren't disabled. Even other physical disabilities, like missing arms, or even legs, don't necessarily prevent walking.

 

Yep

there’s the issue with most of the ME/CFs stuff - not just juniors, yet you’d hope the fresh blood might have spotted it or have been keen to fix it if the critical thinking and research design in their education was right:

to say that they needed to have design based around that research question if they wanted to make the claim of 'benefits vs disbenefits'

which almost certainly meant longitudinal and much longer term EDIT: and NOT retrospective so 'those who did more were more well' became the misnomer vs a trial seeing if more exercise/exertion (in total noting people cut back on other things often) = better or worse health.

now we do have better overall exertion monitors (which I’d hope could be programmed to output data that only covered what was needed detail wise so wasn’t such a privacy issue as doing the opposite aka in MEA proms list of all those activities which aren’t exhaustive vs measuring ‘exertion and impact’ ) this is surely possible

and with GWI injury if it was down to patient consent and willingness and researchers were honourable and transparent to build trust I can’t think of a more likely group to volunteer to do long term in the name of getting to the bottom of things ?

 

Indeed it’s 50% less than before - so a lot of very fit or able people often g eg hidden under that ‘but you still pass the tests so you can’t be ill’ nonsense giving the talented people no leeway

plus we don’t know when PeM hits fir all we know due to different cause or different fitness before it could be ‘cumulative’ and hit hugely after a week if they were used to 29mile daily marches and are now just doing one or ‘a bit more than normal’ etc


Who knows how this all calibrates if we aren’t listening and watching for these things?