Mountain Biking - exhaustion = puke why?

its not often that i exercize to the pount that i want to puke but i was wondering if anyone could explain the the chemical reaction that causes the sensation.
point being that i was in the wiss and road a much hard trail than i'm used to lots of hike-a-bike.

That is your bodys way of getting rid of excess lactic acid, which is caused by intense workouts (i.e sprinting, biking very hard, etc.).

That is your bodys way of getting rid of excess lactic acid, which is caused by intense workouts (i.e sprinting, biking very hard, etc.).


So how do you prevent it?

the usual explanation is the following: when you start to exercise the body uses phosphocreatine, glycogen and glucose in the muscles and liver as fuel to burn. If you exercise for long enough these phosphocreatine, glycogen and glucose reserves run out and the body starts to burn fat. Although fat has more energy it is more difficult for the body to burn and it takes some time for the body to switch to fat burning. This leads to a drop in energy levels and an increase in lactic acid levels which in turn results in you feeling pukey

So you are saying the reason this has happened to me can be somewhat attributed to the fact that i went on a very tough ride without eating before and could possibly be prevented by eating correctly during and before the ride.

So you are saying the reason this has happened to me can be somewhat attributed to the fact that i went on a very tough ride without eating before and could possibly be prevented by eating correctly during and before the ride.

I think that not eating before a tough ride would speed up the onset of PK/glycogen/glucose depletion (and therefore pukeyness). If you want to avoid this it would be a good idea to load up your body with carbohydrates prior and during the ride as much as possible. If you do this then you can have about 2000 calories (Kcal) on hand which should last a while (couple of hours at least) then you can try and top this up as you ride.

I think that not eating before a tough ride would speed up the onset of PK/glycogen/glucose depletion (and therefore pukeyness). If you want to avoid this it would be a good idea to load up your body with carbohydrates prior and during the ride as much as possible. If you do this then you can have about 2000 calories (Kcal) on hand which should last a while (couple of hours at least) then you can try and top this up as you ride.

At the same time, fueling up with too many carbs could cause you to feel like your going to puke. You have to find a happy medium. Don't eat right before you ride, wait a good 45 minutes before you take off.. that way your body has a little bit of time to digest some of the food.

wow thats all good stuff to know . back when i was into body building i would just do things text book and never run into lil things like that and i dont think that i was exposed to the same knowlege base as now .
soo thanx i learned something new today

I think that you're over-doing it when you get to that point. Once you're in great shape, it rarely happens, but until that point, get used to it if you push yourself too hard....

its not actualy lactic acid buildup which causes the desire to puke, that just casues muscle burning and fatigue

lack of oxygen to digestive proccess casues the pukyness, and this is casue all of your oxygen(while not realy, but all you have in the right places) is being used to prevent you from making the lactic acid

the issue is in the differance between aerobic respiration and anerobic respirtation, most people had this in high school bio, where your body converts from burning the dietary carbs and protiens and switches to metabolizing sootred fats and protiens(muscle), this isnt becasue you run out of carbs and protiens its becasue you run out of oxygen with which to burn them

so the simple answer is that you need to breate more, and if thats not possible then your pushing yourself over your VO2 max and are already going as hard as you can

yeah when my buddy feels like puking, i just tell him to breathe more. sometimes when i can't breathe fast enough, i feel that gag reflex coming, but i just keep breathing and it eventually subsides.

its not actualy lactic acid buildup which causes the desire to puke, that just casues muscle burning and fatigue

lack of oxygen to digestive proccess casues the pukyness, and this is casue all of your oxygen(while not realy, but all you have in the right places) is being used to prevent you from making the lactic acid

the issue is in the differance between aerobic respiration and anerobic respirtation, most people had this in high school bio, where your body converts from burning the dietary carbs and protiens and switches to metabolizing sootred fats and protiens(muscle), this isnt becasue you run out of carbs and protiens its becasue you run out of oxygen with which to burn them

so the simple answer is that you need to breate more, and if thats not possible then your pushing yourself over your VO2 max and are already going as hard as you can

the lack of oxgen is a consequence of the increased difficulty the body has with burning fat compared to carbohydrates. Fat burning occurs via a metabolic pathway called beta OXIDATION. As the name implies you need a significant amount of oxygen to burn the fats. The limiting factor in how fast the body can burn fats is how fast they can be taken up by the muscle tissue and how fast oxygen can be brought in to burn them. This use of oxygen does NOT stop you making lactic acid. In fact it leads to an increase in lactic acid because the lactic acid is produced by anaerobic breakdown of carbohydrates. When there is insufficient oxygen present carbohydrates cannot be fully burnt up and turned into carbon dioxide but have to be partially burnt thereby producing lactic acid. This is only a short term solution to the energy gap however because lactic acid is a metabolic dead end. It causes pain in the muscles and pukeyness and the debt has to be paid when the body´s energy requirements decrease, i.e. when you rest and breathe. It is only then that the lactic acid can be burnt. Normally proteins make a very small contribution to energy production in the body.

the usual explanation is the following: when you start to exercise the body uses phosphocreatine, glycogen and glucose in the muscles and liver as fuel to burn. If you exercise for long enough these phosphocreatine, glycogen and glucose reserves run out and the body starts to burn fat. Although fat has more energy it is more difficult for the body to burn and it takes some time for the body to switch to fat burning. This leads to a drop in energy levels and an increase in lactic acid levels which in turn results in you feeling pukey


Wow, thank you. I couldn't for the life of me remember all that exactly happens when the body switches to burning the complex carbs that are normally stored as fat.

the lack of oxgen is a consequence of the increased difficulty the body has with burning fat compared to carbohydrates. Fat burning occurs via a metabolic pathway called beta OXIDATION. As the name implies you need a significant amount of oxygen to burn the fats. The limiting factor in how fast the body can burn fats is how fast they can be taken up by the muscle tissue and how fast oxygen can be brought in to burn them. This use of oxygen does NOT stop you making lactic acid. In fact it leads to an increase in lactic acid because the lactic acid is produced by anaerobic breakdown of carbohydrates. When there is insufficient oxygen present carbohydrates cannot be fully burnt up and turned into carbon dioxide but have to be partially burnt thereby producing lactic acid. This is only a short term solution to the energy gap however because lactic acid is a metabolic dead end. It causes pain in the muscles and pukeyness and the debt has to be paid when the body´s energy requirements decrease, i.e. when you rest and breathe. It is only then that the lactic acid can be burnt. Normally proteins make a very small contribution to energy production in the body.

I actually understood all that, but I've got to say, "you've got too much time on your hands!" Whew!

J/K dude!

EAT 5 SLIM JIMS BEFORE BIKING.
ok maybe thats exaggerating. but eat suttin with protein, fat, or carbs
not sugar
sugar will burn off too quick
and even carbs will only last you two hours
i reccomend fats-protein
a ham sandwich with extra ham, works well. lots of energy, pay attention in science class :-p

"a ham sandwich with extra ham, works well. lots of energy, pay attention in science class :-p"

that was a long time ago