Exhaustion in ME/CFS, what is it and what causes it - discussion thread

I used to bike about 20K every day without a problem. When I was looking for fodder to fight the insurance company I paid for two consecutive days of CPET testing at an educational facility that normally tested high performance athletes. The results were disappointingly consistent across the two days. When I asked the tester if there was anything unusual in the results, she said I generated lactate like I was 20 years younger.

Currently I do very brisk walking every morning for about 40 minutes without much problem or PEM. If a try to do a second walk 6 or 7 hours later it is much more difficult, having to concentrate for each step, bit the next day I'm fine to go again.

That said, most of the rest of the day I'm lying flat. If I go to a restaurant, one hour is fine, but two is exhausting and there is PEM the next day.

 

What data did they measure? VO2Max across the 2 days itself is not useful because it measures maximal oxygen delivery by the heart/lungs, rather than peripheral limitations (because it occurs at submaximal motor unit recruitment -the microciculatory and mitochondrial capacity is not fully utilised).

The key measurement is performance at the ventilatory threshold which is normally lower on the second day as increased type III/IV muscle afferent feedback lowers motor cortex excitability and so the ventilatory threshold occurs sooner since the upstream drive (and hence ventilatory drive) is stronger to achieve the same power output. When percived exertion is reported (typically on the borg scale), we also see that the nonlinearity in rated exertion also occurs sooner on the second day.

 

It was about seven years ago. There wasn't other testing so it was the best available. I seem to recall starting the process by sending them information from Bateman Horne and they said they could do the same tests

It was sports fitness testing at an educational facility that did testing of high performance athletes. When the result was unremarkable and no significant difference the result wasn't suitable for the insurance company so I dropped it.

 

It is quite likely they focused on VO2Max because Bateman Horne (and others doing such testing) did not explicitly state key measurements at the time and those experienced with athletes tend to focus on it. This could be a case of the results being unremarkable because they didn't measure the right thing.

 

There are two things I really appreciate about this forum.

First is the critical and science based approach. Second is the knowledge, experience and expertise of many of the participants.