What everybody gets wrong about CNS fatigue 

I remember in High School taking a sports science class taught by a former world class cross country skier, he taught about overall fatigue in just this way, and how stress related to exams, relationships, family, etc. all were contributing factors to keep in check, and plan around, in order not to over train.

ties up with Haberman s quote, you first give up mentally but your physical body still can keep going

I think we should distinguish between CNS Fatigue and Systemic Fatigue. In my view, Systemic Fatigue not only includes CNS Fatigue but also joint and soft tissue pain, performance breakdown and/or psychological fatigue or a “Wanting a reset” feeling. I feel those are good indicators of when we should deload, just my 2 cents

Makes perfect sense. Fatigue is at least in part a safety mechanism to keep you from damaging yourself.

I'm taking one dose of pre-workout for every time Menno says fatigue in this video

Excellent content. Appreciate your choice of topics and showing how the evidence supports your narration.

I am always happy and enlightened after watching your videos. Thank you, Menno, for your discussion of the difference between mental and physical fatigue and putting to rest the overused term "CNS fatigue."

Lovely! Putting hard training and its effects and feelings in perspective

Very interesting. Thank you Dr Henselmans

I really needed this. Great video!

Wow this was very eye opening for me, thank you.

Great video, very interesting info . My client PR’d her squat on Monday and didn’t get much sleep last night. Instead of going easy on everything today, we held back on deadlifts and pushed her accessories and chest exercises with no issue.

Yeah I don't know man I do have my doubts. Ever since I've trusted and been mindful of my fatigue through out my workouts I've significantly reduced injury, and improved results. When I did not do so, and thus trained heavy consistently for many months without deload, I would stagnate and stop progressing. I do believe that some people are better than others at accurately evaluating their true fatigue levels compared to others. And I can see how that can create a huge spectrum of people who fail to see that their mental fatigue has not much to do due to overtraining but actually due to other factors. However for myself, when I pushed on despite of intense fatigue, I only dug myself a bigger hole... With bigger injuries.

Excellent content. Thank you!

A lot of the "cns fatigue" people associate with heavy lifting doesn't come from the heavy weight but with all the psyching up they do before they lift. They keep tapping into their adrenaline stores then blaming the weight on the bar for how they feel the next day. You can just lift a tiny bit lighter without the mental exertion and recover a lot quicker.

Good to see you on here Menno. It's been a while. This video also illustrates a good reason to not do cardio before resistance training (in most situations).

very interesting and enlightening! when I think of CNS fatigue I usually think of the way my body and mind feel near the end of an aggressive strongman training block. It feels central but that is probably because every muscle is being used all the time, coupled with the mental fatigue from needing to be in a state of peak arousal for every lift. makes sense

I'm on board with the idea that 'CNS fatigue' is an umbrella term with distinct components, from local neuro-muscular fatigue to overall psychological fatigue. Gym bro is going to point out that tired is tired, and nobody is going to have a great workout when their psychological fatigue makes their 6+ RIR feel like 1RIR. If you just keep training after that deadlift PR, the odds that most of it is just junk volume are pretty good.

You and Mike have changed the game

pushing past when your body is telling you not to train anymore, makes you weak? no man I think that gets you injured. I can’t believe you said that.

What about inflammatory responce to training stress? Increased cortisol levels, a bunch of pro inflammatory cytokines that are realesed by muscles into the blood, etc. I assume if you train a lot of muscles very hard, this will have a noticable impact on your whole system that doesn't have anything to do with CNS. I think this is one of the reasons (if not the main one) why some people want to puke after multimple sets of heavy squats for example.

thank you for the insightful video

I was really surprised at how well researched your video is. And I wish you had left a link to your book, it's not pushy when you have connected it so well to the subject matter of your video. Additionally, I usually buy my books through the Google Play Books store. Did a search there and couldn't find yours. Just thought I would share my search intent and method.

Awesome video

i am amazed, this was a gold mine

This is awesome. I do have a hard time with the notion that it's simply effort fatigue though that occurs towards the end of a big workout that might make us feel overall fatigued even in muscle groups we didn't train that day.. Even if it's not CNS or neuromuscular fatigue, it seems like there would still be some bioenergetic explanation such as having less resources from which to generate ATP, and perhaps something hormonal. It's VERY hard to believe that's just mental. Thanks for the content!

holy moly, I had no idea that steady state cardio had such an effect on CNS output.

Hmmm... there certainly seems to be central fatigue, unless my leg muscles being tired causes my immune system to dip and my throat to get an infection. I don't really do any endurance training, but if I resistance train hard for more than about 6 weeks and don't deload, I feel run-down and generally unwell. If I ignore this and carry on, I then start getting throat and ear infections. It's not about pushing through laziness. I would much prefer not to have to deload. It pisses me off to be honest. Feels like a week wasted - I love working out, but I feel less and less well if I carry on until I'm forced to stop by being tired and sick enough to be bed-ridden for several days. Perhaps it's not via the mechanism of CNS fatigue, I'm fine with that, but I'm not ready to believe that (resistance) overtraining syndrome doesn't exist, especially as numerous peer-reviewed studies have explored various aspects of OTS, which includes immune system suppression, etc.

Very interesting information. Will you touch on what this means for workout length, assuming one can beat mental fatigue? Is it worth going ahead and training a fresh muscle group i.e. lats, even though we are very fatigued from squats? Or will lat training suffer because we can't bring sufficient intensity? This whole mental aspect is very interesting. I appreciate the classy way you promote your book. Excellent content.

Enjoyed!

Woow... this is great news! That means I can resistance train every single day, as long as I stagger the muscle groups throughout the week. :)

I had a two week CNS fatigue period at the end of my four month bulk with german volume training (10x10) and it was mainly the squats that did it because the program only had 1 minute rest periods. The squats, deadlifts, even bent rows and overhead presses turned into heavy cardio. It was like being outside of my body; I couldn't focus on anything nor actually feel my body to any normal degree. Everything felt surreal and out of control, like a dream. Very frustrating, but at least I learned that if you're unsure if you have it... then you don't.

This video was 🔥

I honestly felt that bicep exericises, because i was able to exert my self immensly while doing them, were extremely fatiguing. My pulse would raise and I would need to catch my breath, it would take me over 2 minutes (sometimes way over) before I was able to perform the next set. Theoretically more fatiguing exercises, like the lat pulldown for example, would in absolutely no way match the fatigue I experienced during bicep exercises. This video help put context into an intuitional observation I have going on for me for quite a while. Noice.

Personal anectode (would live Meno's opinion if he reads this) Recently I kept getting stonger thru weeks 6,7,8 of my last block. I kept thinking "wow I guess I can continue pushing the strength" Mid session on a hack squat i have started getting exertion headaches and for almost 2 weeks i couldnt push myself too hard or I'd get the massive headache. Had to take a good week of rest and then bring up the intensity slowly again, and keep it well managed

thank you

Great Video Menno!

Menno, We need a video on how to increase vertical jump please.

Ended it with a banger of a quote.

This is why I love the 4-6 rep range. Maximum stimulus without all the extra fatigue.

Extremely insightful 🙏 thank you sir. Seems my CNS gets fried when discussing with vegans for some reason

actually makes sense if you think about it.. the more localized it is the stronger the signal sent to the brain. its like that browser tab that eats up way more ram than the other and the computer needs to focus most of the effort there, close it and all goes back to normal. it can serve and maintain multiple low requirement processes

They called me an idiot for saying this "the CNS will nog fatique by doing a little strength training..... it absolutely will not even damage. The CNS is build for what it does, just giving signal to the muscles....

Mind = blown.

Do you have any insight into the concept of "yoke flu," a state of illness seen in Strongman competitors the day after doing heavy yoke carries? It seems to be a result of the supramaximal axial loading. Also, I think a lot of the common discussion of "CNS fatigue" centers around the deadlift, and is more a result of local fatigue in the paraspinous muscles and often inefficient mechanics that shift the fatigue there as "primary movers" instead of into the hips and legs. I've done programs where I deadlift 3x a week and never saw any recovery detriment once I was acclimated to the program and had good technique. Most modern powerlifting programs follow a DUP approach and have very high frequencies, with high frequency on deadlift once considered a no-no.

I used to think I had CNS fatigue, when I completed my last set of heavy rack pulls, I experienced strong respiratory & muscular fatigue, I also read somewhere that cns fatigue could kill you , so I stopped doing rack pulls..

I'd be interested in a followup on systemic fatige. Some people conflate it with CNS fatigue, which is clearly incorrect, but I feel there is too much anecdotal evidence for systemic fatigue and it's respective symptoms (low training motivation, lethargy, etc) to write it off altogether. There's something to be said about lifters who are obsessed with the sport and love it, finding themselves with these symptoms often to the detriment of their higher volume/frequency goals when they have plenty drive and motivation to get the job done regaurdless. While it may be strictly physchologically driven, I'd be interested in a roundtable on this topic. During MASS office hours Eric Trexler and Dr. Zourdos shared a similar perspective on systemic fatigue to Menno, but I feel like it's still not full understood.

This is definitely wrong. If you measure your handgrip after a few hard trainings, it will be reduced a lot compared to your baseline. And it’s definitely not a local fatigue, and not a psychological issue

From switching my primary focus from strength to endurance training I've actually noticed my energy levels increase and overall fatigue/lethargy to be way less than with only strength training. I wonder if this is just an byproduct of making my cardiovascular system more effective? Also after aerobic training session my mood noticeably increases, while weights doest seem affect my mood after at all. Do you know if theres any difference in strength vs aerobic training for mood?

any ways to add some endurance to motor neurons? or get them to recover quicker?

The boy genius 🧠

What about "stimulus to fatigue ratio" that dr Mike speak a lot, does it mean I should reintegrate deadlift for me and specially during a cut a feel the difference in the recovery part by removing big exercice like the SBD

please make more videos :)

Huh, now I'm more confused. 8 months ago House of Hypertrophy had a video on CNS fatigue, and after I watched it I realized my migraines happened at the same time I would be suddenly weak.(Pullup count dropped from 10 to 2 when I felt "migrainey") So I trained endurance to build my nervous system and pretty much cured my migraines. Now I'm wondering if I truly understood the mechanism or just did the right thing by accident.

Never had a fever or super tired, weak grip when waking up from doign a "bicep only" workout the day before.... had plenty of those days when doing heavy full body, to the limit barbell lifts...

@menno Do you mean neurological when adressing the mental? I think it would be good to make distinction between them. Hormonal or general dopamine storage is not equal for all. If these are depleted because of hard training, just willing to go as hard is not possible.

Normally I do cluster sets which cause a lot of fatigue and next day DOMS. Yesterday I did escalating weights for one rep each close to my 1RM, I did not feel fatigued and I don't have any soreness today.

I think there was an axial load component to what Isratel said, but anyhow I think there is something else beyond mentql fatigue as well. Systemic can be metabolic too.

I think just saying mental fatigue is psychological but not central nervous is an oversimplification. The ability to force oneself to do an unpleasant task is limited and has correlating biological mechanisms in the brain. It is just not as simple as muscle physiology.

Learning this should I do 3 sessions of cardio in one week and 1 the week after or 2 and 2

most of those studies use only 80% of 1RM and some of the participants was even not trained. It is big diference going for 1RM max that for reps with lower weight. I can go deadlift 2x times per week with 80% and not overtraine but traing the same with 1 rep max will definitly make me fatigue

I find this difficult to believe, because that would imply signals of mental fatigue/tiredness/feeling worn out are just entirely subjective noise that is disconnected entirely from the body's potential for perfomance. The best performers would then be the guys that completely and indefinitely disregard their own state of mind and I don't think that is the case.

It's soft tissue fatigue/damage, which feedbacks to the golgi tendon apparatus which limits power/strength output. Not central but peripheral. Muscle don't have this feedback beyond being exhausted during exercise, or damaged and Not functioning.

It's about the spinal loading, I believe. That is why deadlifts seem to wreck me far worse than bench

Anyone who lifts heavy knows for a fact that systemic fatigue is real. Maybe you're right and it's not caused by the mechasim you mentioned, which is the most popularly touted reason for it. Maybe it shouldn't be called CNS fatigue. Maybe it's an entirely separate phenomenon that should be investigated. But you can bet it's a real and cumulative longer term effect over days and weeks, and is systemic in nature, meaning whatever exercise you fatigue from affects your performance in all others.

Always wondered about the truth of cns from deadlifts. I've never noticed any issues.

why is then measuring the grip strength a good indicator of "cns" activation ? or is it just a coincidence because the hands are involved in almost all exercises ?

“Feelings don’t necessarily correspond any physical reality” in which world does that make sense?

Holy shit, this is Pacific Rim all over again. 800 Diesel Engines per muscle strand.

What is the definition of fatigue experienced when cognitive or sensory functions are used for an extended period, such as a long exam, big presentation, or hunting? Does it not impact neuromuscular drive?

The real problem is systemic fatigue that feels like being exhausted even hours after the work out. That happens to me a lot although i eat and sleep a lot. This seems like overtraining but i never had significant performance drop in a work out, but i feel a huge drop after the work out in doing daily physical activities and mental tasks until i sleep. Any tips?

Rhabdomyolyses and CNS fatigue, is there a colleration?

Interesting... I've had chronic epilepsy for at least 53 years, with 35 years of experience with strength training. I've noticed that (in my case) strength training does not cause epileptic seizures, but extended periods of intense cardio do. CNS fatigue and epileptic (tonic-clonic) seizures - causation or correlation?

Great

What about prescription stimulants and caffeine causing CNS fatigue?

Your computer example is ironic cause constantly opening and closing an app can cause memory usage errors that will slow down or "fatigue" the system

Above all else, this video taught me that even people consuming digestible scientific information concerning a certain topic in their free time don't necessarily have the mental faculties to interpret what they read/see/hear. Or rather understand it properly, in the first place. I always got so angry whenever I read or saw any report on anything regarding my personal field of study because the media would just misrepresent it to the point of sometimes saying the opposite of what a given study found. But reading the comments here, I finally understand: people are just as bad with logic as they are with precise comprehension. Just look at everyone in here trying to debunk things you never even said. It'd be hilarious if it weren't frightening. If you want to actually discuss this (counter to the ideas presented), don't say sth. as lazy as "this can't be true bc it doesn't match my felt experience". That's an argument from incredulity. Worthless. Look at the data that the conclusion came from and find an alternative conclusion matching the data. That's how science works. If you want to debunk it, actually debunk it instead of just saying "nuh uh".

5:10 idk , I did the deadlifts the other day and then did bicep curls and I just couldn’t contract my bicep like I usually can. After Deadlifts I literally feel like my CNS is fried and can’t get the mind muscle connection I usually have

Did Menno really hit us with Facts dont care about your feelings?

With ADD and a life on medication to counter a different CNS, I find this very interresting. The dopaminergic /norepinephric system can get quite fatigued even on meds (dexamphetamine or methylphenidate). But a short reset of 30 min sensory deprivation and a sitting nap will massively reduce this particular type of CNS-fatigue, and will let the drugs kick back in. I have no idea of how it happens, maybe there is a positive feed back loop when these neurotransmitters are being fed into the system, with significantly reduced drainage from sensory and cognitive stimulus…

I'm confused. If CNS fatigue is purely local, would this mean that having multiple daily sessions for different body parts would be a lot more viable than we would think it is?

What do we call it when over training results in a lower immune system and people report getting sick of it. I have experienced this myself after intensive training.

What is the difference between cns fatigue and psychosomatic disorder fatigue?

Im lost on this, im trying to get to 6 sets of 12 on bench press but most I can do is 11 with a 3 to 4 second eccentric, on the sixth set it will go down to 8 reps, but if i rest for 45 seconds to a minute i can do three more. Is there a difference between muscle fatigue and muscle failure, how are they related, I can easily do three more sets of 8 in the same manner but cannot reach my goal of 12 reps. I get a different fatigue when doing leg press, intense burning and if try to do another rep it begins to cramp my legs but never a full on cramp. When doing curls Ive gotten to where I lift with both arms to try to do an eccentric and the weight just drops, absolutely no muscle contraction. What am I missing ?

very interesting take, although some part of this must be hogwash, since if neurological fatigue is only local in nature it would mean you don't ever need rest between exercises since you're doing other muscle groups. But how come immediately after a set of squats or leg press even forearm training is insufferable?

What is the mechanism of the local nervous system fatigue? Is it the buildup of metabolites, or the consumption of certain neurotransmitters or something? Electrolytes?

How far can we take this logic? Does this means it never makes sense to rest when we feel 'fatigued' (except local fatigue, pain or sleepiness)? If not, why?

I'm not saying it's right or wrong but the issue with studies like that is that they're most of then done on either untrained people or very causal gym goers. Which makes them pretty biased.

If you think for one second that jogging or bicep training is as systematically fatiguing or MORE than heavy deadlifts and/or squats then you've never deadlifted or squatted heavy. You don't need a study or experiment to know this, just try it. I will say REAL endurance training is taxing but after you reach a certain threshold or start training somewhat consistently recovery becomes much easier short of running a marathon, that's the adaptation part. Weightlifting is the opposite. The more muscle you have, the longer it will take to repair and recover as long as the damage is proportional to what you did at a previous size. Your body can only heal so fast. I'm sure it's possible your body could adapt to healing faster or more efficiently to some degree but only so much, you'd have to do a study on it. I'll single out biceps, calves, abs, traps or forearms, etc. a lot on my rest days, work that one muscle or muscle group hard and feel totally refreshed and recovered mentally and energy wise the next day. Regardless if it is officially "cns" fatigue or some other type of fatigue, it's fatigue. I could jog and/or power through a few days of bi's in a row and know I could actually still give a decent effort days into it waaayyyy before I could squat and/or deadlift heavy several days in a row no matter what the readout on the machine says or where the fatigue originates from.

Whoa ! 😯

How exactly is cns fatigue measured?

I guess this is an arguement in favour of co trolled but not slow tempo of eccentrics as opposed to Mike Isrataels slow eccentric approach. Have to weigh up what’s more of an injury risk, the central fatigue from eccentrics or the soft tissue injury risk of faster tempo

Interesting. Well, the psychological fatigue IS basically neurological (brain) + endocrine system fatigue, which are main regulatory/control systems influencing our "performance" in everyday life, exercise included. An even broader "systemic" fatigue if it truly exists and can negatively impact training probably also includes accumulated connective tissue damage (to the extent that it can be sensed neurologically) and even some unfavorable immune system response/fluctuation (a slight secondary transient "immunodeficiency" for a lack of a better term).

and here im watching eric janicki telling me to train this way and not that way to avoid cns fatigue...

More reason to do lower rep ranges

Yes but how do you explain that after a AMRAP of deadlift, in the following days you are not literally able to do anything? Sometimes I got flu after very heavy workouts. It's all about inflammation? Pls search with me an answer

This proves that body builders and power lifters (maybe more the first ones) could benefit a lot from mind fullness meditation. Imagine a mini meditation spot next every single gym...omg

Hmm. Interesting. But I wonder what you mean when you say that the brain is like software and doesn't tire? Is that really true? Don't neurological impulses tire the system? When I was a student in Japan and spoke Japanese all day I was totally exhausted at night. You call this psychological and effort adverse. But I loved learning the language. Same when practicing the piano. After a while you get tired and have to take a brake. Is this just psychological? And doesn't have a physical cause? What is it then? This confuses me.

I appreciate the science and all the studies backing this up, but my personal experience is pretty much the opposite of all that is being stated here.

So CNS fatigue is mental fatigue? or I didnt understood correctly?