Muscle nocireceptors (group III/IV afferents) appear to be sensitive to many substances associated with contractions/high metabolic strain (e.g., K+, ADP). Based on rodent studies, lactate seems to be on that list, but maybe not very high up on it.
In any case, 1) it’s just a theory (although an easily testable one, e.g., does bicarb ingestion mitigate the issue for anyone), 2) perceived exertion is dependent upon both central activation and peripheral feedback (so it might be easier to hit the “puking threshold” under some conditions vs. others), and 3) there are undoubtedly other factors that could contribute to nausea during intense exercise (e.g., diversion of blood flow away from the gut, which is what I assume can sometimes give me a little pit-of-the-stomach queasiness).
I got sick a number of times in high school after running the 400m (it’s about an all out 50sec effort). I only ever got sick once on a bike after doing an all out 4min effort for training/testing purposes. That was after being out of the saddle for about the last 90sec
Loads of experience with nausea and puking. So much that I consider it par for the course when doing all out efforts. In my case it’s also linked to exercise-induced asthma which makes me cough + retch after max efforts. It’s not nice but it is what it is…
When I go ‘past my limit’ I have a really weird half a minute or so immediately when I stop. As well as being totally gasping for air, I feel like I might puke, piss and shit (all involuntarily) all at the same time.
I thought I was the only one like this but I know at least one of my riding buddies experiences exactly the same thing.
Luckily none of these things have actually occurred (yet!)
I always get nauseous at approximately my max heart rate. It is basically the first symptom to tell me to back off and of course I have to at that point or will throw up.
The latter two (actually, all three) are controlled by the parasympathetic nervous system. I have therefore always interpreted the urge to urinate after a really intense effort as being due to massive activation of the parasympathetic system, attempting to restore homeostasis.
@oldandfast I think you’re on to something. It’s long been my hypothesis that if you make the blood to acidic the body will ‘dump ballast’ by jettisoning some acidic liquid…from the digestive system.
But I’ve certainly demonstrated to myself that I can up-regulate lactate transport w/in the body to make it virtually impossible to raise blood lactate enough to induce ballast dump. When I was a strength athlete it was no problem to attain blood lactate levels in the high teens. Now I can’t do double digits.
If you check Lionel Sanders YouTube channel you’ll find he has some frustration with low blood lactate readings in spite of some very hard efforts. He’s got such a trained lactate transport system that it’s just hard to accumulate blood lactate. Also, see my Green MCT up-regulation comments previously on this forum.
I have never experienced nausea nor vomited due to the effort across any sport I’ve played and I’ve definitely gone maximal as a runner and cyclist at efforts across the spectrum of duration that are common to this.
I listened with interest on a podcast (I can’t remember if it was Empirical Cycling or Inside Exercise) where they were talking about nausea/vomiting after intense efforts being something that was more prevalent in more fast-twitch/anaerobically dominant athletes. Anecdotally that would make sense since I’m not really that. Also kind of lines up with this “acid” theory I’ve never heard before given the production of H+ related to lactate/pyruvate production in glycolytic ATP production.
Edit: should’ve read the thread first, I see @The_Cog already hit on this in a much more informed and intelligent fashion.
Well definitely if I have to yak that will cost me time.
But in the end cerebral oxygenation is probably what really throws the switch. Or at least it’s very hard to resist fatigue if cerebral oxygenation drops more than 5%.
YES! I race mountain bikes and am constantly limited towards the back 20% or last lap by nausea. I’m basically pinned HR wise and even small drinks of water will cause nausea to the point I just have to dial it down. The best method to reducing this has been to take in all calories / food / drink by the 50-60% distance, then just manage the desire to take in food. And especially pick your match burnings at those distances and further. Unfortunately it usually means podium spots, but otherwise my recovery lasts all week if I go all out to late in the race. My investigations into this are blood flow diversion from the stomach to muscles, extremities and brain to cool and power under extreme loads overrides digesting. This is generally a pace beyond the maximum you can achieve during training, it’s race induced and very difficult to replicate on my own. The nausea has been my crutches for 30 years of racing, but it’s hard to give in to it. Oh and throw in some hi heat and humidity for quicker results.
This is my experience, as well, and usually happens in either a) the tail end of a ramp test (thank you AI FTP detection for not-having to suffer through that) or b) anywhere in the last few reps of long (2+ minute) VO2max efforts – I’m looking at you, Spencer +2, you son of a dog.
Back when I was doing one of those two things, I would have to tell my wife “look, if you hear me gag or dry-heave a couple of times, don’t worry, it’s just One Of Those Workouts”.
Oddly enough, I’ve never actually puked when I reach the point of dry-heaving, but it’s definitely something in my brain trying to get me to stop.
"While defecation delayed cycling time to fatigue, participants under defecated and non-defecated conditions reached similar levels of deoxygenation at the time when exercise can no longer be persisted. "
Nausea nope, but taste of blood in relatively short efforts such as 3 to 5 min, yes. Did yesterday, for example. I had a 5-minute test and hit my all-time 5-minute power. The taste of blood was present and took 5m - maybe more, don’t know to precise - to disappear.
It’s not nice but it is what it is…
