AEROBIC versus ANAEROBIC respiration.
This needs some clarification I think - I'll try! The first time I heard it said that our aerobic systems were broken, and that we needed to rely on our
anaerobic respiratory pathways, I got confused, because in biology it is quite clear: humans cannot live without aerobic respiration.
Here's how I have reconciled my biological understanding re: aerobic versus
anaerobic respiration.
Note: I was a biology teacher before ME stole my active life. I'll start with some definitions.
"Aerobic respiration" means using air, or more specifically oxygen, to respire glucose (and other food molecules) to provide energy.
"Respiration" is the metabolic process of extracting energy from food molecules. This happens in all cells of the body to provide energy.
"Anaerobic respiration" means the respiration of food molecules
without oxygen. This involves alternative metabolic pathways to aerobic respiration and results in the build up of acids in the tissues.
Anaerobic respiration provides only about one 16th of the energy per unit of glucose as aerobic respiration. It is thus very inefficient, and cannot be sustained for long. It is really an emergency means of providing energy, when oxygen cannot be delivered to the cells fast enough. (Note: I've highlighted the "
an" in
anaerobic respiration throughout this piece to help clarify which is which! For me, and my readers! LOL)
So here's the confusion. Higher life forms such as humans require aerobic respiration to survive! We cannot survive on
anaerobic respiration alone: if we could we wouldn't need to breathe at all. So ME patients cannot have a
totally defunct aerobic respiration system.
So, when Workwell say our aerobic systems are "broken", I think what they really mean is that, we cannot
ramp up our aerobic systems like healthy people can.
I suspect some of the confusion comes from those "AEROBICS" classes that lots of us took in the eighties. The class I went to (back in the day) pushed us to "feel the burn", and to get out of breath. So technically, they were really "
anaerobic" classes, because we were pushed to exercise at a level that we could only sustain for a short time - ie the exertion we attempted, tapped into
anaerobic respiration. However attending these classes no doubt also helped us to improve the rate at which we could respire aerobically. In short we got fitter. So the classes improved our overall aerobic capacity - perhaps that's why they were called "aerobics" classes?
Note: Getting fitter, as I understand it, means a body can:
a) get oxygen to all the cells more efficiently (improved lung capacity, heart efficiency, and improve capacity of the blood/red blood cells to carry oxygen etc).
b) respire more effectively at cellular level (improved mitochondrial structure, number etc - meaning more enzymes to actually carry out the respiratory reactions that release energy).
c) remove lactic acid more efficiently (once oxygen is available) - thus allowing quicker recovery from those periods of
anaerobic respiration.
Yet those "aerobics" classes cause confusion, because we now associate "aerobic respiration" with having to skip about in leotards and leg warmers! In fact, we are already respiring aerobically when we are at rest! (However, we are not pushing that aerobic level to one that increases our heart or breathing rate, which is what most people call "aerobic" exercise.)
So back to exercise and anaerobic respiration: When we (any person, not just ME peeps) want to do more, we need to ramp up our breathing and heart rates to ensure that oxygen reaches the muscles that require it. However, there is a time delay between starting to exert ourselves, and the required oxygen arriving at the muscle cells. During the lag time, the muscles will not have enough oxygen - so the cells respire
anaerobically, while they await the arrival of the increased oxygen supply. Athletes "warm up" for this very reason - it means the supply of oxygen is already pumping to the muscles at the required rate, by the time they start their race or whatever.
So my interpretation, is that we - ME peeps - cannot
ramp-up our aerobic pathways as normal folk can. (This could be at cellular level, or it could be at the level of heart, lungs and blood supply not supplying oxygen efficiently enough.) Thus, if we cannot ramp-up our aerobic pathways normally, then we are immediately compelled to use
anaerobic respiratory pathways to supply the energy deficit.
Anaerobic respiration is not very efficient, so not much energy can be produced this way. (And don't we know it!)
I assume that there must be some adaptation to
anaerobic respiration that means that the more often it is used, the better it can function. However
anaerobic respiration is not sustainable and this means that no matter how efficient it becomes, it is a short-term option only. As I understand it, using
anaerobic pathways for as long as possible causes the build up of acids in the tissues, which will a) reduce the ability of the tissue to function in the moment, and b) over time cause harm. I think major caution is needed for ME folk with this, and this is why Workwell suggest very short periods of effort only.
Further, using
anaerobic respiration creates an "oxygen debt". This means oxygen is required to remove the acids built up during the period of
anaerobic respiration. Breathing and heart rate will remain high until those acids are cleared. I certainly note that my heart rate stays high for quite some time after exertion.
In truth I'm not wholly convinced that training our "
anaerobic" pathways to be more efficient, will give us much extra functioning - at least not anything like normal functioning. Although perhaps, during recovery from these episodes (assuming the sessions are kept very short, as I have seen Workwell recommend) we will have some increased activity of heart and lungs, and perhaps that will help us to improve fitness a little?
I don't know. I'm certainly very cautious about any reference to the words "exercise" and "increase" - especially when they are used together!
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Another note on exercise:
As I understand it, people who can get fit normally may go through two periods of
anaerobic respiration during a period of exercise:
1. When they are warming up. Anaerobic respiration is required until heart rate and breathing rate catch up with the demand for oxygen. So this temporary
anaerobic episode is quickly replaced by the ramped-up aerobic respiration. Fit individuals can then exert themselves for lengthy periods. Some
anaerobic respiration may occasionally be used to top up the energy supply - eg when the runner goes up an incline, however, once the oxygen supply is ramped-up some more, the fit runner can continue aerobically for some time.
2. When they try to sustain exertion above their fitness level. At this point
anaerobic respiration will kick in again because there is no more aerobic capacity to ramp-up. Soon, acids produced from the extra
anaerobic respiration will accumulate. This cannot be sustained. Cramps, lethargy, etc result, and the individual slows down.
In my view people with ME never get that ramping-up of their aerobic capacity, so we go straight from one
anaerobic scenario to the next with no sustained higher aerobic activity in between.
We do not have that wonderful aerobic capacity to just keep going. Marathon runners for example have very efficient aerobic capacities, and can keep on running. We don't. So we very quickly flag once we try to do anything. (I have a friend who recently did a 24hour race! Yup 24 hours running! I went to cheer her on at 23 hours into her race, and even though she had dropped to a walk for a short rest break, I still couldn't walk at her pace for even 20 metres!! Meh!).
Anyway, I think Workwell are right, we need to do things in short doses, with rest times in between to allow recovery. However I'm not so convinced that careful activity of this nature can "improve" us enough to aim to "increase" activities towards anything like normal functioning.
As may know, I monitor my heart rate and use it to judge what I do. If I rest after doing a "thing" and my HR doesn't drop as I expect it to, then that is my sign that I need to pull back. Heart rate remains high whilst there is an oxygen debt (pay back from
anaerobic respiration) and so watching my HR can help me judge how well I am recovering from an activity episode.
Anyway - hope that isn't too rambley. I think there is much that we can do to help ourselves. BUT my view is still, that any activity management we engage in, is most useful when thought of as keeping within our "energy envelope", and not as a means to aiming to "increase" what we do.
"Increase" is only possible after healing, and as yet we don't know how to heal ME.
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PS. "
Respiration Rate" is the rate at which glucose molecules are being respired to produce energy in the cells. This can be roughly measured by measuring an individual's breathing rate. "Breathing rate" is often called "respiration rate" in medical circles. This leads to a confusion that the word "respiration" means the act of "breathing", but that is not technically correct.
Breathing rate will, of course, often correlate with cell respiration rate, hence the reason it is used as a proxy measure.
PPS - This got longer than intended. I might turn it into a blog post.... so if you spot any typos, tell me now. Cheers!
PPPS -Edits to bold "
an" in a few more "
anaerobic" words;
predominant aerobic 
