Review Attenuating Post-exertional Malaise in [ME/CFS] and Long-COVID: Is Blood Lactate Monitoring the Answer? 2024 Faghy et al

So is this venous blood or more likely just blood from traumatised micro vessels during a pinprick?

Presumably it measures lactate in skin dermis at some peripheral site like the fingertip?

If peripheral circulation is slow would that raise the level because of greater de-oxygenation?

Would it bear any useful relation to lactate in tissues of interest like muscle - which it will not sample unless you stick the needle in pretty far?

I can see that a blood prick test might be quite a reliable way to assess major systemic lactic acidaemia but I wonder if it fraught with problems if interpreted as a measure of muscle lactate production.

 

I think in sports (which is where this paper seems to be coming from) they very often use the ear lobe as well (and that might even make a difference according to this study Differences between lactate concentration of samples from ear lobe and the finger tip).

The newly hyped, soon to be available, devices that are continuous lactacte measurement devices are wearables that seem to be extremely similar to those glucose arm patches so they would use some sensors, to measure lactacte in sweat or interstitial fluid, instead of blood sampling.

 

Which sports exercise the ear lobes? Is there a study that relates earlobe blood lactate with lactate in major muscles elsewhere in the body? To me it seems like measuring "Pacific Ocean temperature" temperature by dipping a thermometer in one bay. I'm not sure that it matters for customers though, since they probably just want to brag about their numbers on social media, so nonsense numbers are as good as any others.

 

None. But afaik that's not the point at all. The point is that the ear lobe lactacte levels are supposed to be used as a reference value to set your training zones (accounting for heart rate and power output) and using the ear lobe can be very easy for that in certain training situations (for example if you're on an indoor bicycle trainer and being monitored by a doctor they can easily and repetitively use your ear lobe instead of your finger).