Well it’s a bit more complex than that. First because you have essentially two types of overtraining, one caused by excess intensity one by excess volume. Both will lead to a decrease in performance and both will make you feel like crap but they will affect different systems.
What us, lifters, most often call “overtraining” (and is not a true overtraining syndrome, it is more often overreaching) is overtraining due to too much intensity (both in the sense of going too heavy too often ot pushing ourselves too much too often).
So in that sense, yeah, neurotransmitters are normally the number one issue.
But receptor desensitization is not the only possible problem. You can also have the depletion of one or several of the excitory neurotransmitters (dopamine, noradrenaline, adrenaline).
So the cause could be:
- Dopamine depletion
- Noradrenaline depletion (leading to lowered adrenaline since noradrenaline is the precursor to adrenaline)
- Adrenaline depletion (more rare)
- Adrenergic receptors desensitization
- Dopaminergic receptors desensitization
NOTE:overtraining via too much volume (most often found in endurance athlete) is more associated with depleted serotonin.
And honestly, while you can gather some clues about which one is the cause it is very hard to know which one is your main problem because the psychological/behaviorial changes are hard to differenciate.
For example dopamine depletion/desensitization will lead to a drop in motivation, lethargy, lack of pleasure, drop in confidence while adrenergic desensitization/adrenaline depletion will lead to a decrease in motivation, less responsive heart rate (less HR increase when training), very even behavior/less passionate/more neutral for example. Kinda hard to know which one is affecting you. And don’t forget that if you deplete dopamine, adrenaline will be affected since adrenaline is ultimately made from dopamine.
When talking depletion it’s a matter of seeing how far in the production chain you need to go back to find the depletion. Because if you deplete dopamine or noradrenaline you will also deplete adrenaline because you can’t fabricate as much.
How can you tell which is affected? Well it’s detective work really and while I can give you some clues, a forum post is not the place to explain the whole thing.
The first thing you need to assess is whether the issue is a depletion of one/several excitory neurotransmitters or a desensitization of the receptors.
There are some tests you can do.
Take 7-10g of tyrosine on an empty stomach in the morning, wait 20-30 minutes and assess whether you feel better or not. If you have a big improvement on mood then it is a depletion issue because providing the body with the raw material to fabricated dopamine (then noradrenaline and adrenaline) fixed the issue which means that your receptors are responsive.
However if the tyrosine doesn’t improve your mood it doesn’t necessarily mean that it’s a receptor sensitivity issue. It could be that your body is inefficient at converting tyrosine into dopamine (this is very often low levels of vitamin B6).
You can try taking mucuna pruriens on an empty stomach. It contains L-Dopa which is the direct precursor to dopamine. So if tyrosine didn’t workbut mucuna worked, then you know there is a problem with tyrosine absorption/transport or a vitamin B6 defficiency.
If neither tyrosine or mucuna made a difference then we are likely looking at a dopamine receptor desensitization issue. Which is actually quite common in our modern society of instant gratification. Keep in mind that blue light (tablets, smart phones, flat screen TVs) are extremely strong stimulants of the dopaminergic receptors. If you abuse them you can desensitize your receptors over time by overstimulating them. The best way to improve dopamine sensitivity is to dramatically decrease the use the the devices mentionned earlier. It can go as far as not using a table, smart phone or TV for 1-2 weeks.
If tyrosine didn’t work and mucuna worked your dopaminergic receptors are fine. It could be another issue too. It can be adrenergic receptor desensitization or noradrenaline depletion.
How can you know which one? That’s a bit harder.
If your noradrenaline is depleted you will have big problems concentrating and focusing, more frequent headaches, a tendency toward low blood sugar episodes. Noradrenaline depletion often occurs when your body chronically produces too much cortisol. Why? Because cortisol increases the conversion of noradrenaline into adrenaline, which canquickly lead to low levels of noradrenaline.
BTW if noradrenaline levels are low, so will your adrenaline levels because you need the first to make the second. That’s why it’s harder to know if the problem is low noradrenaline or adrenergic desensitization. Problems concentrating is normally the big symptom to look at.
So if tyrosine didn’t work but mucuna did. And your concentration is messed up then it’s likely noradrenalin depletion. In which case lowering cortisol would be your best bet since it would decrease the conversion of noradrenaline into adrenaline, allowing you to gradually increase your stores back up. You can also use quercetin to extend the duration of the adrenaline so that you don’t need to produce as much, “saving” noradrenaline.
If tyrosine didn’t work, mucuna did and your concentration is not affected it is either a problem with the adrenergic receptors. And the best way to solve that is to decrease adrenergic stimulation for a while. This means decreasing cortisol, phosphatidylserine, ashwaganda, glycine and magnesium glycinane or taurate will be your best tools.
And in reality the issue is even more complex than that. Because the problem could come from serotonin. If serotonin is too low the body increases the conversion of dopamine into adrenaline (it’s a way to try to balance serotonin and dopamine) and if serotonin is high then you will convert less dopamine.