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Lactic acid/lactate- how often do you feel it? (Read 740 times)

    I would like to know more about this aspect of the physiology of running.

     

    My understanding, so far as it goes, is that lactic acid is produced by running hard enough and long enough that the normal process of using oxygen to "burn" glycogen as a fuel for the muscles cannot keep up with the demand for fuel.

    By activating the anaerobic energy system to fuel our muscles we produce lactate or lactic acid (are these two names for the same thing?) as a byproduct.

     

    I can only be sure of having felt the stinging pricking of lactic acid in my legs once, at the end of a half marathon run at absolute maximum effort.

    I cannot remember ever feeling this after running interval, a 10 mile hard tempo, or other half marathon races.

    I do not understand why this would be so- perhaps I am lucky enough to produce less or clear the lactic acid more quickly from my bloodstream than most people?

    Perhaps because I am older my legs are not strong enough to let me run fast enough for long enough for this to become a problem?

     

    I would like your help in coming to a better understanding of this aspect of our sport- thanks!

    PBs since age 60:  5k- 24:36, 10k - 47:17. Half Marathon- 1:42:41.

                                        10 miles (unofficial) 1:16:44.

     


    Feeling the growl again

      Production of lactate is a continuous variable, not binary.  In other words, production will increase with effort....though the slope of the line varies...but there is not some point where it's like flipping a switch and you turn the process on.  You produce some even at comfortable speeds.

       

      People develop a tolerance for lactate with training.  Perhaps some other component of your conditioning limits you from getting to the point where you "feel the burn".  When one does a lot of race-specific training for, say, a mile or 5K, over time you get to the point where you can both produce and tolerate higher lactate levels.  You can push yourself a lot further in those shorter races.  If you don't do that training, however, you will not be able to push yourself to that same sensation.

      "If you want to be a bad a$s, then do what a bad a$s does.  There's your pep talk for today.  Go Run." -- Slo_Hand

       

        Do you race 5ks?  I always feel it by the end of a 5k, even up in my arms, as my blood acidity increases dramatically by the final half mile.  Half marathons are less likely to produce this because HM race pace turns out to be just a scosch slower than lactate threshold (where the rates of accumulation and clearing cross) pace, or so I understand theoretically.  My personal experience would seem to confirm this.

        - Joe

        all running goals are under review by the executive committee.

          I think most physiologists in recent years have mostly moved past associating the burn that you feel in the later stages of the race with lactic acid. Lactate is actually used as a fuel for the muscles. Its role in glycolysis is more complicated than most of the training literature makes it out to be. Though spaniel's mostly right about what he says (and certainly is better trained in physiology), I am not so sure that "tolerate" is the word to use with regard to lactate production, as the lactate is not only tolerated -- it is used!

           

          So, basically, I would say:

          a) the hard burn in the muscles is not necessarily a sign of accumulated lactate. Certainly it is not the "acid" "burning."


          b) spaniel and joescott did a good job answering your question. If you want to feel the burn and really experience it, I suggest trying sprinting at 100% effort for 400m. Please report back on your findings!



          I'm back!

            The Lactic Acid Myths

             

            Everything you’ve been taught about lactic acid is wrong.

             

             

            Lactic Acid Is Not Muscles' Foe, It's Fuel

             

            As for the idea that lactic acid causes muscle soreness, Dr. Gladden said, that never made sense.


              Feeling the growl again

                I think most physiologists in recent years have mostly moved past associating the burn that you feel in the later stages of the race with lactic acid. Lactate is actually used as a fuel for the muscles. Its role in glycolysis is more complicated than most of the training literature makes it out to be. Though spaniel's mostly right about what he says (and certainly is better trained in physiology), I am not so sure that "tolerate" is the word to use with regard to lactate production, as the lactate is not only tolerated -- it is used!

                 

                So, basically, I would say:

                a) the hard burn in the muscles is not necessarily a sign of accumulated lactate. Certainly it is not the "acid" "burning."

                 

                b) spaniel and joescott did a good job answering your question. If you want to feel the burn and really experience it, I suggest trying sprinting at 100% effort for 400m. Please report back on your findings!

                 

                 

                Jeff is correct that it is not "acid" "burning", in fact note that I said lactate, not lactic acid.  In solution it is not in the acid form in your body.  The notion that lactate is the cause of fatigue has been debunked.

                 

                As for fueling muscles...every byproduct in your body can be recycled and used for fuel.  Darn near everything except the nitrogen wastes excreted in your urine.  Lactate CAN be used for a fuel....but not at a high rate, during exercise, without oxygen.  Lactate is produced as an end electron acceptor to produce energy fast without oxygen.  This is a wasteful, short-term proposition that gives you a higher energy output for a short time but eventually you have to pay the piper.

                 

                For lactate to be used by muscles to produce energy, it must be converted back through the same biochemical pathway by which it was created and metabolized using oxygen to pyruvate and on through the typical aerobic energy producing machinery.  There is, therefore, no reason to produce lactate in the first place unless the cells feel a reason to need quick energy in excess of what they can produce with oxygen.  It is not some magical fuel which somehow gives more than was put into its creation, or somehow turbo-boosts muscles during exercise.  There are some reports I have reviewed which dispute this but they have issues and any change is far from at a consensus.

                 

                In fact, skeletal muscle mitochondria, where all aerobic respiration takes place, cannot even metabolize lactate.  That happens anaerobically in the cytosol.

                "If you want to be a bad a$s, then do what a bad a$s does.  There's your pep talk for today.  Go Run." -- Slo_Hand

                 


                I'm back!

                  For lactate to be used by muscles to produce energy, it must be converted back through the same biochemical pathway by which it was created and metabolized using oxygen to pyruvate and on through the typical aerobic energy producing machinery.  There is, therefore, no reason to produce lactate in the first place unless the cells feel a reason to need quick energy in excess of what they can produce with oxygen.  It is not some magical fuel which somehow gives more than was put into its creation, or somehow turbo-boosts muscles during exercise. 

                   

                  In fact, skeletal muscle mitochondria, where all aerobic respiration takes place, cannot even metabolize lactate.  That happens anaerobically in the cytosol.

                   

                  I don't believe this is the current thinking, at least according to Brooks, outlined in my two links above (though of course it doesn't somehow give more than was put into its creation).

                    Thanks for responding so quickly.

                    I had read that it is used as fuel by the muscles, possibly in Noakes' "Lore of Running", and I guess I realized without having ever put it into those words that there is a continuum, not off/on like a light switch.

                     

                    I have run a 1,000m time trial a few times in 3:50-4:00 (don't laugh!), but don't remember any special sensation from that, possibly I just don't remember.

                    I will try the 400m test.

                    PBs since age 60:  5k- 24:36, 10k - 47:17. Half Marathon- 1:42:41.

                                                        10 miles (unofficial) 1:16:44.

                     


                    I'm back!

                      I don't believe this is the current thinking, at least according to Brooks, outlined in my two links above (though of course it doesn't somehow give more than was put into its creation).

                       

                      More specifically,

                       

                      Mitochondrial lactate oxidation complex and an adaptive role for lactate production

                       

                      The intracellular lactate shuttle (ILS) hypothesis holds that lactate produced as the result of glycolysis and glycogenolysis in the cytosol is balanced by oxidative removal in mitochondria of the same cell. ... This ILS emphasizes the role of mitochondrial redox in creating the proton and lactate anion concentration gradients necessary for the oxidative disposal of lactate in the mitochondrial reticulum during exercise and other conditions. The hypothesis was initially supported by direct measurement of lactate oxidation in isolated mitochondria as well as findings of the existence of mitochondrial monocarboxylate transporters (mMCT) and lactate dehydrogenase (mLDH). Subsequently, the presence of a mitochondrial lactate oxidation complex (composed of mMCT1, CD147 (basigin), mLDH, and cytochrome oxidase (COX)) was discovered, which lends support to the presence of the ILS.

                       

                       

                      though oddly, this does seem to conflict with pr100's Lestrun link above, written by a lactate metabolism expert and student of Brooks:

                       

                      Specifically, tissues like the heart and highly oxidative skeletal muscle are excellent consumers of lactate (taking it up, converting it to pyruvate and then using the pyruvate in oxidative metabolism in the mitochondria) ...

                       

                      and

                       

                      Instead, most of the lactate was going to other tissues where it was being converted to pyruvate and metabolized as a fuel in the mitochondria.

                       

                       

                      I may well be misunderstanding this apparent conflict.


                      A Saucy Wench

                        Walking away from bad breastfeeding joke.  Carry on

                        I have become Death, the destroyer of electronic gadgets

                         

                        "When I got too tired to run anymore I just pretended I wasnt tired and kept running anyway" - dd, age 7

                          I cannot remember ever feeling this after running interval, a 10 mile hard tempo, or other half marathon races.

                           

                          Maybe your hard tempo is not hard enough for your fitness level.

                           

                          My personal experience is this: In my early few months training, my heart and lung could allow me to go faster, but my legs were not strong enough. If I forced myself to ignore my legs feeling and go faster, next day I got sore legs. If your heart and lung allows you to go faster, maybe you can try going faster and see if you can feel lactic acid.

                           

                          My another interesting experience is that I just keep running next day even when I feel sore legs. A couple days later it just disappears. Maybe that is the way to build my fitness level. From the time recorded, I can tell that I can run faster and feel not as difficult as before.

                           

                          All the theories I read say that you should run just under your lactate threshold and maybe the end go faster to accumulate some lactic acid to tell your body to increase the threshold and build it gradually. But I try something different. I guess I am still a beginner and my weekly mileage is low (only just over 20 miles), so it is easier to recover.

                           

                          One thing is the injury risk when the legs get too tired and the running form changes. I pay particularly attention to my form when I get tired. Also I try to do some cross workout as much as I can to improve my core strength, flexibility, joint mobility.

                          5k - 20:56 (09/12), 7k - 28:40 (11/12), 10k trial - 43:08  (03/13), 42:05 (05/13), FM - 3:09:28 (05/13), HM - 1:28:20 (05/14), Failed 10K trial - avg 6:10/mi for 4mi (29/08/14), FM - 3:03 (13/09/14)

                              Thanks for responding so quickly.

                              I had read that it is used as fuel by the muscles, possibly in Noakes' "Lore of Running", and I guess I realized without having ever put it into those words that there is a continuum, not off/on like a light switch.

                               

                              I have run a 1,000m time trial a few times in 3:50-4:00 (don't laugh!), but don't remember any special sensation from that, possibly I just don't remember.

                              I will try the 400m test.

                               

                              If you've run a 1,000 time trial and didn't feel the burn, then you didn't run it fast enough.  (not trying to be a jerk). 

                              - Joe

                              all running goals are under review by the executive committee.


                              just a simple cat

                                I always thought the hurty feelings in my legs was just my metabolism trying to get me to take a nap instead of running hard. 

                                I can use the lactate created as subsidiary fuel is bonus!

                                 

                                I  guess as you get more bodacious, you begin to lose more brain cells, because there is a limit to how much magnificence your body can house

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