Sub-maximal endurance exercise does not mediate alterations of somatosensory thresholds. Kortenjann et al. 2020

[John Mac]

Mentions ME and CFS

Exercise-induced hyperalgesia, the phenomenon of increased pain perception following exercise, is more likely to be observed in patients with conditions such as myalgic encephalomyelitis, chronic fatigue syndrome, fibromyalgia, or painful diabetic neuropathy. It has been suggested that a different response of the immune system—which is already weakened in certain chronic diseases—partially contributes to this phenomenon. The increased sensitivity to exercise in musculoskeletal pain has also been linked to psychological factors such as catastrophizing and inability to disengage, as well as other processes related to the central sensitisation of pain

Physical exercise has been shown to alter sensory functions, such as sensory detection or perceived pain. However, most contributing studies rely on the assessment of single thresholds, and a systematic testing of the sensory system is missing. This randomised, controlled cross-over study aims to determine the sensory phenotype of healthy young participants and to assess if sub-maximal endurance exercise can impact it.

Results
Time × group analysis (2 × 2) could not detect any significant differences between groups over time (p > 0.05; see Table 1)
There was also no statistically significant difference detected when analysing difference scores (p > 0.05; see Table 2)17. Z-profiles indicated no differences between groups, nor did we detect deviations larger than the twofold standard deviation within our study group, which would indicate pathologic findings.

There were no differences in systematically assessed sensory thresholds pre- and post intervention. A 30-min long submaximal physical workload did neither result in exercise-induced hyperalgesia nor hypoalgesia.
Our data are in contrast with some previous studies, which suggested exercise-induced alterations of sensory thresholds.

https://www.nature.com/articles/s41598-020-67700-4

 

[Snow Leopard]

This study is notable for using a variety of pain threshold tests.

• Thermal Testing comprising cold and warm detection thresholds (CDT, WDT), paradoxical heat sensations (PHS) during the thermal sensory limen procedure (TSL) of alternating warm and cold stimuli and cold and heat pain thresholds (CPT, HPT).
  
  
• Mechanical Testing comprising mechanical detection thresholds (MDT), mechanical pain thresholds (MPT), mechanical pain sensitivity (MPS), dynamic mechanical allodynia (DMA), the wind-up ratio (WUR), vibration detection thresholds (VDT) and pressure pain thresholds (PPT).

I suggest that any studies on Fibromyalgia or CFS or ME should also use this more robust methodology.

I also suggest changes in pain thresholds if detected in some patients may suggest something else is going on peripherally or spinally, resulting in increased sensitivity.

 

[rvallee]

I can't really see the value in papers that make judgment calls such as perceived pain. It's purely a judgment call made by an external observer, it has no basis and no place in medicine as long as we can't objectively measure pain.

Physical exercise has been shown to alter sensory functions, such as sensory detection or perceived pain

Lowering it. I mean we're humans with brains, intelligence and memory. Many of us had a normal life before, we have life experience in what things do to our bodies. Physical activity lowers pain perception. That's why athletes can endure pain that normally would make them wince and stop, or how we can laugh at pain that came about in a silly or entertaining way. The opposite is completely abnormal and does not come about by magic, ghosts or cosmic dragons.

catastrophizing and inability to disengage

Enough of this crap. It's vague and has no basis in evidence, nothing but a cheap judgment call. This reads more like religious admonition than anything having to do with science. Whatever follows this moral judgment cannot be of any use, it is tainted by a false premise.

Let's bring back some neutrality and objectivity into medical science. Way too much judgment, opinions, beliefs, ideology and all types of unscientific influences going on, even more problematic that they are often treated as axioms, things that don't even need to be proven.