@andyguitar Hey! Yes, I still benefit from cold showers. They provide relief from malaise and nausea that, for me, are telltale signs that I've overdone it. The mechanism may be cold thermogenesis, I'm not sure.
There are some caveats to what I wrote here last year. Looking back, it's now obvious to me that I was stuck in a chronic PEM. I've had moderate to severe ME for about a decade now, and I never realised that it was possible to feel like anything but royal garbage 95% of the time. By dialling back my activity level to absolute zero I was able to find a floor where I'm not 100% rubbish 100% of the time, and that in turn has allowed me to better map my (painfully low!) activity limits.
What I wrote about cold showers last year should be interpreted in this context of chronic PEM. Back then, I was continually desperate for illness relief, and only cold exposure could bring it. I routinely did Wim Hof-style cold drenches at very low temperatures. (I took my showers as icy as water temperatures permitted!) They "calmed" the body and took away the sickness feeling like nothing else could.
Now that I'm out of chronic PEM, a few things have changed. I've gone from "sick but never sick" to having colds that flare up whenever I'm too "active", and that wane when I better respect my limits. Which is really hard by the way - it means I cannot do any reading, go up or down the stairs, have much of a meaningful conversation, and especially not do any PC work, which for whatever reason wrecks me like nothing else. In any case, I'm tempted to hail this as a sign of progress: now that I'm not constantly exceeding my limits, has my body (finally) gone back to fighting whatever latent infection(s) plague it? I recall JaimeS writing about a similar "progression path": the first post-ME diagnoses common cold was a triumph.
Weirdly it also means that, while I'm still helped by cold exposure, I've also become susceptible to *catching a cold*. I wish I could explain why, but I can't, I only have my personal observations. If I take a freezing cold shower today, I end up sick. Not ME sick, but *sick sick*, with a stuffed nose / sinuses. As such I'm far more careful and cautious about full-body cold exposure. I still treat my neck and forehead this way; it seems to speed up recovery from cognitive effort (like writing this message)! My body I now merely cool, not chill.
Hope that helps!