Wanna know how much of a fitness nerd I really am?

I hit a major wall physically & mentally with my training on Friday.  It was a serious wake-up call that I need to change something - not only now, but with how I approach my recovery & deloads in the future.  So, what does a guy like me do when this happens?

First, I sit down and eagerly plan out my deload week.  Yup, had far too much fun with that, too.

Second, I research…and not just foo-foo google search stuff…this kind of stuff (see, told you I was a complete fitness geek):

This one comes from Romain Meeusen’s team at Vrije Universiteit in Belgium. Meeusen is another name that catches my eye for all of his work on the neurochemistry behind central fatigue, and this paper is another piece in that work.

Folk-theories of fatigue suggest that muscles just get tired, but we’re discovering more and more that it isn’t so simple. In exhausting exercise, whether from endurance or high intensity, the brain’s output starts to decline and that decline eventually affects performance. It’s almost like your brain itself gets tired.

Which is pretty much what happens. Much of Meeusen’s previous research has focused on the three monoamine neurotransmitters, dopamine, serotonin, and norepinephrine, which dominate the motor-control pathways in our brains. In this study, Meeusen’s team tested the effects of two different drugs, one which elevates dopamine (DA) and another which elevates norepinephrine (NA), on cycling performance. The result is interesting because it shows that excessive NA impairs performance, whereas NA is typically the “arousal” chemical, with its networks responsible for “turning everything on”. For reference, caffeine and ephedrine work by activating NA nerves.


Why does this matter? Mainly because strength athletes can undergo something similar. Max-effort intensity and strongman-type exercises that fatigue you both do this magic on the brain, and it isn’t always a matter of “tired muscles” that leave you floored. As I’ve said so often in the past, you can make yourself exhausted just by focusing too hard for too long; the brain centers that control emotional output also control motor output. Volume aside, TRAIN TO FAILURE OR GO HOME!! thinking can lead to burn-out just as easily as — if not easier than — “high volume” training.

Use your RPEs, folks.

The second paper ties right into that suggestion. These pathways between brain and body work in two directions. Again the folk-wisdoms suggest that we “damage” our bodies with exercise and these signals filter up to the brain, which then freaks out, but it’s not so simple.


Skeletal muscle catabolism is a co-morbidity of many chronic diseases and is the result of systemic inflammation. Although direct inflammatory cytokine action on muscle promotes atrophy, nonmuscle sites of action for inflammatory mediators are less well described. We demonstrate that central nervous system (CNS)-delimited interleukin 1β (IL-1β) signaling alone can evoke a catabolic program in muscle, rapidly inducing atrophy. This effect is dependent on hypothalamic-pituitary-adrenal (HPA) axis activation, as CNS IL-1β-induced atrophy is …. data suggest that a significant component of inflammation-induced muscle catabolism occurs indirectly via a relay in the CNS.


The problem starts when either 1. the stress happens repeatedly, such that the HPA never gets a chance to turn off or 2. when your HPA, for whatever reasons, doesn’t settle down after you get wound up. Chronic elevation of the HPA and cortisol levels will become a problem.

Set off that cascade by doing lots and lots of training, or training while sick, or any number of activities that would qualify as “overdoing it” and you really are going to cause problems over the long-term.

Cortisol in itself is not the real issue. Bodybuilding folk-wisdom worries about the hormone, but as you can see there’s an identifiable cause in the chain: namely the inflammatory cytokines, and the brain’s response to them. The hormone just does its job; what concerns us is the “upstream” causes — the brain, and the immune-system signals that are altering it.

In training, central matters far more than peripheral; training to deliberately get yourself sore, training to exhaustion at every opportunity, that’s all activating this inflammation-HPA pathway. But even that’s not a huge deal unless you’re one of the truly obsessive personalities that won’t rest for anything.

It’s amazing to me how many people will struggle to control cortisol by fiddling with their workouts and taking crazy supplement regimens that don’t do anything, and completely neglect everything else in their lives. It’s the everything else that really matters, and this paper handily demonstrates why: chronic matters far more than acute. If you live your life in a constant state of Switched On, expect to be sick more often, to have worse subjective “recovery”, and to respond very poorly to anything that pushes you out of the norm.

4 notes


  1. blissmanifesto said: I salute your immense nerdiness, Sir!! Have fun with resting… I know it’s not so easy to do but I guess you really need it.
  2. ironwarriorstraining posted this

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