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Fatigue Is a Brain-Derived Emotion that Regulates to Ensure Protection (2012)
- im3w1l 10y ago2012
- taneq 10y agoThis meshes perfectly with the general view of endurance athletes that performance is largely mental. If fatigue was strictly limited by lactic acid buildup then your state of mind wouldn't make such a dramatic impact.
- kev009 10y agoThere are different kinds of fatigue though. When I go running, it's some kind of aerobic sensation, but eventually my thoughts shift when it's time to stop. If I lift heavy things for an hour, I can also be quite winded but there's usually some gas left in the tank I just know it's better to get some rest and allow muscle to repair. Some kind of crossfit style workout, yet another sensation. Sometimes I can take a nap as soon as I get home after the above, especially a vigorous run in the Arizona desert during summer. Knowledge work has its own fatigue for me. If I go deep into flow state while working on something, eventually I reach a generalized mental haziness, where I want to relax and let my mind wander or be passively entertained. Usually I have trouble sleeping after intense thinking, mind still firing but not effectively. I just want to "chill" and watch TV or do something simple and rewarding like clean the house to try and bring it fully out of gear.
- crikli 10y agoLactic acid buildup does not have the relationship to fatigue that you are implying. Common myth. For more and in from far more knowledgeable persons than me: http://www.scienceofultra.com/podcasts/10 http://www.scienceofultra.com/podcasts/10
- wallflower 10y ago> This meshes perfectly with the general view of endurance athletes that performance is largely mental. Most elite endurance athletes do not hit the lactic threshold during their actual races. That is why they train so much - to build their endurance. Once you hit the lactic threshold, your body starts to break down.
- mantas 10y agoEnduramce athletes go just bellow lactic threshold most of the time. The body is OK to go above threshold, but only for a limited time. The key is to correctly time usage of that above-threshold capability. I race MTB. Both quick races and long, 100 miles or even 24h solo events. In a quick <3h race, I just go all-out and stay above threshold most of the time. But I try to time my above-threshold usage in long races. In one of the 24h races, the course had a single climb. I was riding everything but that climb bellow threshold. It would have been very hard to stay bellow threshold on it. While it was just a couple minutes effort above threshold.
- deciplex 10y agoAnyone who has gone to the gym after a protracted absence and loss of fitness will have some intuitive understanding of this. Your brain hasn't quite gotten the memo that you're not in the shape you used to be, and it's really easy to over-exert yourself. You feel fine during the workout, then throw up afterward and take much longer to recover.
- cpard 10y agoVery true. I learned this the hard way, in my case I ended up with a stress fracture. My mind was actually refusing to get the memo, even when I started feeling pain.
- yuningalexliu 10y agoIn light of this article, wonder what type of psychological training could be used to complement the typical physical training to improve athletic performance?
- gryphonshafer 10y agoMaybe something that copies military basic training. It has been decades, but I can still hear my drill instructor yelling, "You aren't tired until I tell you you're tired!" He was right.
- Aelinsaar 10y agoI think cadence marching/running is pretty helpful too. You just focus on left foot, right foot, and the words.
- cel1ne 10y ago"Your body is lying to you!" is the nicer and actually correct thing to say :).
- sangnoir 10y ago> I can still hear my drill instructor yelling, "You aren't tired until I tell you you're tired!" He was right. I wonder why Rhabdo[1] isn't more prevalent in basic than it is. 1. https://en.wikipedia.org/wiki/Rhabdomyolysis https://en.wikipedia.org/wiki/Rhabdomyolysis
- gryphonshafer 10y ago>90% of fatigue in basic (based on a scientific study I just made up in my head) is mentally induced because recruits have a belief of their limits that's short of reality. Part of the drill instructor's responsibility is to demonstrate these limits are just mental by pushing recruits beyond them. Of course, that still leaves the <10% of times when the limits are real and someone gets hurt, but that's just collateral damage, I guess.
- ilaksh 10y agoI can buy the conclusion except that I believe you can only usually tweak performance in small degrees without actually over-exerting yourself, since the central nervous system _is_ in fact an expert on what you are capable of doing safely.
- cpncrunch 10y agoI think the point is that you can keep increasing performance in small degrees, so it's kind of like training your brain to allow small incremental performance boosts by saying "see, I didn't get injured or die, so give me another 1% speed". Of course, sometimes this does actually result in injury, so if you want to be safe it's probably best not pushing too far.
- towlejunior 10y agoIf the claim is that muscles don't fatigue, then I am skeptical. In college, I took a weightlifting class with a bunch of athletes in it. One day, we did lunges (no weight) around and around, in a line like ants. Nearing the end, my brain thought I was totally fine. I cannot stress that enough. Bam, like a light switch, my legs went from 60% strength to 2% three quarters of the way through the last lap. Had the instructor not caught me, I would have fallen right over.
- fernly 10y agoNo, I think you are anecdotally supporting the posted article: you worked your muscles to physical exhaustion but you did not feel "fatigue", ergo, the conventional theory that "fatigue" is caused by lactic acid or other muscle chemistry is disproved.
- jcoffland 10y agoWhat result would disprove the article?
- ndonnellan 10y agoI would recommend reading the article, it is fairly interesting and suggests based on the body of research that the brain (subconsciously) creates the emotion of fatigue prior to muscle "exhaustion" to prevent injury. "These sensations of fatigue are unique to each individual and are illusionary since their generation is largely independent of the real biological state of the athlete at the time they develop."
- lj3 10y agoWhy do you suppose your legs went from 60% to 2% so rapidly? Do you think your muscle really depleted in function that quickly, or did your brain cut off the electrical signals to the leg in order to protect it from permanent damage? But you're correct in that there is more to it. Adrenaline masks fatigue. It allows you to temporarily exceed what your brain would normally allow you to do in order to save your life. You pay for it later, though.
- cpncrunch 10y ago
- gwern 10y ago'Protection' might be the goal of physical fatigue, but it doesn't work for intellectual effort - what are you being 'protected from breaking' by not being able to write another line of code? Carpal tunnel? In that case, it looks more like it's about conserving energy or rotating to another task after having spent so much time on one task: "A Meta-Analysis of Blood Glucose Effects on Human Decision Making" http://www.gwern.net/docs/2016-orquin.pdf http://www.gwern.net/docs/2016-orquin.pdf , Orquin & Kurzban 2016 "An opportunity cost model of subjective effort and task performance" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3856320/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3856320/ , Kurzban et al 2013
- bshanks 10y agoSimilar to the opportunity cost model, Minsky proposed that boredom with tedious tasks is a guard against getting stuck in an infinite loop: http://aurellem.org/society-of-mind/som-6.13.html http://aurellem.org/society-of-mind/som-6.13.html
- mrleinad 10y agoWell, maybe for the same reason we need to sleep every day. The brain also experiences fatigue.
- dietrichepp 10y agoPerhaps from bad decisions? As I stay awake, the quality of my code drops pretty fast, social decisions get worse, I say the wrong thing to people, et cetera.
- gwern 10y agoThis is question-begging. 'We get fatigued because we get fatigued.'
- dietrichepp 10y agoThat's conflating two different senses of fatigue. "We feel tired to prevent us from making mistakes when we have been awake a long time." That separation of the different senses of fatigue is the core of the article. Fatigue is both a feeling and a state, which we confuse because they are connected. But you can give someone drugs, like diphenhydramine or caffeine, which change the feeling of fatigue without changing the underlying state which that feeling normally reflects.
- js2 10y agoDr. Noakes, the author of this paper, wrote the "Lore of Running", which may be descibed as the bible on running science: http://www.humankinetics.com/products/all-products/lore-of-running-4th-edition http://www.humankinetics.com/products/all-products/lore-of-r... https://en.m.wikipedia.org/wiki/Tim_Noakes https://en.m.wikipedia.org/wiki/Tim_Noakes
- liquidise 10y ago"Fatigue makes cowards of us all" is a famous quote supposedly from Vince Lombardi, though it has also attributed to other significant people (as famous quotes often are). Regardless of the speaker, the overlap with the headline is remarkable.
- bootload 10y ago"conscious mental decisions made by winners and losers, in both training and competition, are the ultimate determinants of both fatigue and athletic performance." A favoutite quote of mine: "You have to make a sustained 'conscious effort', to win."
- mrexroad 10y agoMy first thought was, "oh, reminds me of the SEAL's 40% rule... so if they're trained to ignore that limit, why don't they get hurt?" Then, in first google result [1], I read this: “I first met “SEAL” at a 100-mile run in San Diego and I was running this race as part of a six-person relay team with friends and he was running the entire race by himself,” Itzler said. “Who is this guy? I’ve never seen anything like it. And during the race, I kept an eye on him and around mile 70 — he weighed probably 260 pounds, which is quite large for an ultra runner — he had broken all the small bones in both of his feet and had kidney damage and he finished the race.” So... yeah, this makes Me think maybe I'll try harder at listening to my body (fwiw, I've screwed up arms/hands twice in past decade by pushing through fatigue). [1] http://thehustle.co/40-percent-rule-navy-seal-secret-mental-toughness http://thehustle.co/40-percent-rule-navy-seal-secret-mental-...
- ArkyBeagle 10y agoWhere does this come from in the larger culture? I can see why people who are soldiers or ... athletes at the varsity or pro level might be interested in it but why would anyone want to basically injure themselves as a ... hobby? I've worked with runners who had serious injury, soccer players who came in with bruises that you'd associate with a severe beating... I'm thinking "geez, it's gonna suck when you're 62." Because when you lose some amount of basic mobility, you lose a lot of the ability to stay healthy when you're older. Is this because of Mountain Dew commercials and 1980s GI Joe body image stuff?
- lj3 10y ago> soccer players who came in with bruises that you'd associate with a severe beating I was a lacrosse goalie in high school and didn't have the sense to wear shin pads. If you run your fingers along my shin, you'll feel divots where the bone never regenerated. I too used to walk around with bruises on my legs that you'd associate with a severe beating. > Is this because of Mountain Dew commercials and 1980s GI Joe body image stuff? It's considerably more primal than that. Sports are the modern equivalent to tribal rites of passage. We're not allowed to kill our rivals anymore, so we settle for beating them in a physical sport in order to establish our physical dominance. It's empowering in a way that few things are, especially as a teenager and extra especially if you were bullied throughout elementary school.
- cel1ne 10y agoI'm doing rather exhausting martial arts, which includes doing all movements at exact the speed in which the trainer counts. There were moments where I felt I couldn't proceed and was exhausted. When telling that to my trainer he, correctly, said: well your muscles aren't shaking under load, so you can't be out of energy yet. After a pause of 10 seconds I was able to go on. In my experience most physical fatigue can be countered by proper, regular and deep breathing during movement. It seems to be an oxygen-distribution problem.
- erikb 10y agonever forget that a different conclusion can also come from a different input. Maybe your understanding of fatigue is not the same as the author's. You could already see two definitions when comparing yours with your trainer's, right?
- known 10y agoIs it same for procrastination?
- TeMPOraL 10y agoMaybe. In my case it's often protection against bullshit things I have to do but I'd rather don't. Sadly, the "system 1" in my brain doesn't understand that it's not just "have to do", it's "have to do, or else...".
- cpncrunch 10y agoPossibly this might explain procrastination: https://www.researchgate.net/profile/Maarten_Boksem/publication/51426280_Mental_fatigue_Costs_and_benefits/links/0f31753a54b2b691ba000000.pdf https://www.researchgate.net/profile/Maarten_Boksem/publicat... It seems to involve the same brain regions that Noakes identified as being involved in physical fatigue. However rather than protecting against damage, its function appears to be to protect against unnecessary expenditure of energy.
- nnq 10y agoThis also makes sense if you think the evolutionary biology of it: if after a small number of top runners separate from the pack (even if they happen to be the "top" runners of a race by pure luck, and even if their relative order is pure luck), it's better if the 2nd, 3rd runner etc. accept their places at a point and don't push more, because then the top runner will also push more and so on... positive feedback loop until some of them (maybe all!) die of fatigue. Cowardice of the individual might be a huge survival advantage for the species as a whole! Without it the species might end up loosing or injuring the fittest of the individuals in stupid competitions. The would be quite detrimental for the species. (Also going even further from physical performance: If you extend this a bit from "athletic race" to "nuclear arms race" you'd see a similar thing ...but yeah, as an individual player you might "loose" by being coward (although I would not call "staying alive" loosing...). And an interesting philosophical question would be about the cases where an individual gains courage by loosing "the feeling of being the same species as the others" - we know that psychopaths ca be quite fearless, and we also know from history that if you train your soldiers to think they are "a superior master race separate from the others" they tend to get quite better at winning battles.)
- oxryly1 10y agoThis is an interesting method of building resiliency -- or anti-fragility -- into a complex system without adding complexity via a system of feedback for each component (or some other such cleverness). (I.E.: Have an overarching "intense activity" timer or measuring device signal that the system is likely to suffer breakdown... just because it probably will.) The key intelligence here comes from the fact that the human fatigue system evolved alongside the human organism, and thus has millions of years of results built in. As a result it's fairly accurate.
- cpncrunch 10y agoI suspect it has been around quite a while in evolutionary terms, and isn't just in humans. All animals need to be careful that they don't overheat, go without water, break a bone, etc. (However if another animal is chasing you, it makes sense to turn off the inhibiting signal). The brain regions involved are common to many animals AFAIK.