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

    Hey, by the way, spaniel, Jeff, bhaern, in the interest of time (mine... Smile) can you at least confirm for me the basic fact that I've always learned that lactate increases (and it must release a Hydrogen ion, too, because blood pH drops, eh?) as you push toward more anaerobic paces.  No?  I understand that this is a completely different question than what it causes it and what it affects, but this is what happens right?

    - Joe

    We are fragile creatures on collision with our judgment day.


    Feeling the growl again

      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).

       

       

      Re the disagreement you were seeing in the two sources, there really is not one.  Brooks' group claims lactate dehydrogenase (LDH) exists in skeletal muscle MTA skeletal muscle mitochondria; other groups disagree and feel the lactate must by converted to pyruvate in the cytosol.  So to me the three quotes you list are not at odds with each other.

       

      pr100's link was very good, I think that was a good summary written in a way most people can get it.  Better than my offhand hastily written post, which I will now attempt to clarify.  Smile

       

      Up front, I remember reviewing Brooks' work before and finding some limitations in it which did not fully support some of the conclusions OTHERS drew from it, in light of the broader body of work on the subject.  It's been a few years since I wrote on this, and I do not recall the details, and I'm not going to read through everything again so I will step past that for now.  I did confirm my recollection via a quick search that Brooks' claim that skeletal muscle mitochondria can directly oxidize lactate is still contentious as other groups have not been able to validate it by other methods.

       

      My point was not really about whether lactate can be a fuel, where it is used,etc.  That is all really beside the point.

       

      1)  The body is a wonderfully evolved, efficient machine.  If lactate were some sort of uber-fuel that was "good" in terms of you should TRY to develop it and want more of it under a given set of conditions, your body would already do this.  It does not.

       

      2)  Setting aside the debate about whether skeletal muscle mitochondria can aerobically metabolize lactate, let's say it can.  At fast paces -- those at which we know empirically produce higher levels of lactate -- you are already at VO2max.  You are using all the oxygen you can.  So you are then going to use lactate instead of pyruvate?  Biochemically this makes no sense to do as your total energy output would DECREASE.  This is the fundamental part a lot of people miss in interpreting Brooks' work -- yes lactate can be used as a fuel, but it's not adding anything to your athletic output.  Brooks helped show lactate is not the red-headed stepchild, but it's not some outstanding new athletic performance driver either.

       

      3)  The article pr100 linked made a good point about "anaerobic metabolism" not necessarily meaning that it is taking place without oxygen present, only that oxygen is not used.  This is how lactate is produced (sans oxygen consumption).  This is a rapid process which produces energy faster than the pyruvate route....so why, you might ask, is this a bad thing?  Why doesn't the muscle just ramp up the lactate production and give fast energy then go ahead and use lactate as a fuel?

               a)  It is MUCH less efficient and therefore wasteful in the longer term, but more importantly,

               b)  It is converted back to pyruvate before being oxidized.  You are right back where you started.  Nothing has been gained by producing

                    lactate if it is converted back to pyruvate and aerobically metabolized.

               c)  There is a limit to the level of lactate you can accumulate.  It does not diffuse freely across cell membranes. 

       

      So what does this mean?  Stop demonizing lactate as a burn- and fatigue-inducing molecule, but still focus on optimizing your aerobic system.  Nothing in training has changed.

      "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

       


      Feeling the growl again

        Hey, by the way, spaniel, Jeff, bhaern, in the interest of time (mine... Smile) can you at least confirm for me the basic fact that I've always learned that lactate increases (and it must release a Hydrogen ion, too, because blood pH drops, eh?) as you push toward more anaerobic paces.  No?  I understand that this is a completely different question than what it causes it and what it affects, but this is what happens right?

         

         

        The faster you go, you get more lactate.  Yes.

        "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!

          Re the disagreement you were seeing in the two sources, there really is not one.  Brooks' group claims lactate dehydrogenase (LDH) exists in skeletal muscle; other groups disagree and feel the lactate must by converted to pyruvate in the cytosol.  So to me the three quotes you list are not at odds with each other.

           

          My point was not really about whether lactate can be a fuel, where it is used,etc.  That is all really beside the point.

           

          Yeah, that's what I'm beginning to gather. I was very into trying to understand this a few years ago, but I guess the jury is still out.

          Is there an intracellular lactate shuttle in skeletal muscle?

           

          I also agree that the details of where lactate is metabolized are beside the point.

           

          And yes, pr100's link was very good.

           

          MTA one last paper link; this looks like a nice review paper on lactate metabolism from 2008.

           

          A ‘‘Lactatic’’ Perspective on Metabolism

           

          ... Although disagreements abound, current evidence suggests that lactate is the primary end-product of glycolysis at cellular sites remote from mitochondria. This lactate could subsequently diffuse to areas adjacent to mitochondria. Evidence is against lactate oxidation within the mitochondrial matrix, but a viable hypothesis is that lactate could be converted to pyruvate by a lactate oxidation complex with lactate dehydrogenase located on the outer surface of the inner mitochondrial membrane. In another controversial area, the role of lactic acid in acid–base balance has been hotly debated in recent times. Careful analysis reveals that lactate, not lactic acid, is the substrate/product of metabolic reactions. One view is that lactate formation alleviates acidosis, whereas another is that lactate is a causative factor in acidosis. Surprisingly, there is little direct mechanistic evidence regarding cause and effect in acid–base balance. However, there is insufficient evidence to discard the term ‘‘lactic acidosis.’’ 


          Feeling the growl again

             

             

            A ‘‘Lactatic’’ Perspective on Metabolism

             

            ... Although disagreements abound, current evidence suggests that lactate is the primary end-product of glycolysis at cellular sites remote from mitochondria. This lactate could subsequently diffuse to areas adjacent to mitochondria. Evidence is against lactate oxidation within the mitochondrial matrix, but a viable hypothesis is that lactate could be converted to pyruvate by a lactate oxidation complex with lactate dehydrogenase located on the outer surface of the inner mitochondrial membrane. In another controversial area, the role of lactic acid in acid–base balance has been hotly debated in recent times. Careful analysis reveals that lactate, not lactic acid, is the substrate/product of metabolic reactions. One view is that lactate formation alleviates acidosis, whereas another is that lactate is a causative factor in acidosis. Surprisingly, there is little direct mechanistic evidence regarding cause and effect in acid–base balance. However, there is insufficient evidence to discard the term ‘‘lactic acidosis.’’ 

             

            Thanks, there was some stuff in there I hadn't read before.

             

            So, in the past I have said it is more accurate to refer to lactate as a reporter (of anaerobic metabolism, or how far you are above VO2max effort) than a waste product or fatigue-causing toxin.  It seems in the last few years there has been enough evidence amassed to also refer to it as another type of energy currency in its own right...one that is produced in areas of low O2 or remote from motochondria/aerobic metabolism (not much surprise there).

             

            The most fascinating thing highlighted by the article was the complexity in trying to understand this as related to localization.  They're not just talking about skeletal muscle vs heart vs brain, or cytosol vs mitochondria; they're talking about even more distinct subcellular localizaiton.  Typical glycolysis in the vicinity of the mitochondria, but more distant from where the pyruvate will be used the pyruvate continues to lactate...diffuses across the cell, or into the bloodstream...then converted back to pyruvate when it reaches a mitochondria and is oxidized.

             

            Again from a training perspective this doesn't change much once you have discarded lactate as a cause of fatigue...but it certainly is interesting from a biochemical standpoint.

            "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

             


            Hawt and sexy

              Andypants and bhearn, you guys are both in trouble for not pming me. I love reading this stuff. And I am getting back into the learning mode for the running process.

              I'm touching your pants.


              Feeling the growl again

                Andypants and bhearn, you guys are both in trouble for not pming me. I love reading this stuff. And I am getting back into the learning mode for the running process.

                 

                Send me your study list and I will make sure I update you accordingly  Wink

                 

                I am glad to hear you are re-primed to the running process and hope to see what your goals are for future efforts.  

                 

                As long as they don't involve tight pants on a certain male skater, of course Smile

                "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

                 


                Hawt and sexy

                  Oh, the usual. Base building. Comparing/contrasting training plans. I am trying to get more into the soft sciences side of thing. I get the physics of running. but, I always had a problem trying to discern what happens to the body during the process of running, especially the more specialized processes and different speeds. I have to relate these to a machine to wrap my head around them. But there must be hope, because I understood what you were explaining. But then, if I recall, I had the best chance of understanding the body processes when you explained them.

                   

                  No goals. Who said goals? It scares me you know that much about me. We are just imaginary internet friends, you know. Or so says the manslave.

                  I'm touching your pants.


                  Feeling the growl again

                    Oh, the usual. Base building. Comparing/contrasting training plans. I am trying to get more into the soft sciences side of thing. I get the physics of running. but, I always had a problem trying to discern what happens to the body during the process of running, especially the more specialized processes and different speeds. I have to relate these to a machine to wrap my head around them. But there must be hope, because I understood what you were explaining. But then, if I recall, I had the best chance of understanding the body processes when you explained them.

                     

                    No goals. Who said goals? It scares me you know that much about me. We are just imaginary internet friends, you know. Or so says the manslave.

                     

                    Don't mind-fudge yourself.  Just run.  A lot.  At different speeds.  Most of it will take care of itself.  

                     

                    And, the manslave does not exist until I meet him.  You drove right past my house and I did not see him.  Wink

                    "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 ran the 400m time trial after a 5k warmup and stretching, followed by strides and a walk to get my breath back.

                      Time 83.07, probably a bit more to come with better pacing. Perhaps a target of 80 seconds for the 400 and 3:00 for 800 would be good goals for next year. My quads felt pumped up and swollen and warm and I was definitely gasping for air, but other than that nothing special. Perhaps I am expecting something too dramatic.

                       

                      Thanks for posting the links, I am going to have to reread, make notes and study them to better understand.

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

                                                          10 miles (unofficial) 1:16:44.

                       

                        I'm sure I've read somewhere that the older you get the less likely you are to feel that burn but I'm darned if I can find the quote. A bit like some elderly people that get fractures (neck of femur) without any apparent pain symptoms involved - seen that in someone myself. As we are both "of a certain age" Simon that might well be one explanation. Certainly I get leg soreness after big efforts but I don't recall that severe burn of my youth.

                        2013

                        3000 miles

                        Sub 19:00 for 5K  05-03-13 Clee Prom 5K - 19:00:66 that was bloody close!

                        Sub-40:00 for 10K 17-03-13 Gainsborough 10K - 39:43

                        Sub 88:00 for HM

                         

                          I ran the 400m time trial after a 5k warmup and stretching, followed by strides and a walk to get my breath back.

                          Time 83.07, probably a bit more to come with better pacing. Perhaps a target of 80 seconds for the 400 and 3:00 for 800 would be good goals for next year. My quads felt pumped up and swollen and warm and I was definitely gasping for air, but other than that nothing special. Perhaps I am expecting something too dramatic.

                           

                          Thanks for posting the links, I am going to have to reread, make notes and study them to better understand.

                           

                          83? what did you come through the 200 in?

                           

                          I didn't say to run a time trial -- I said to attempt to run a 400 at 100% sprint effort from the very start. Sure, you'll blow up, but you will learn about the burn.


                          Feeling the growl again

                             

                              attempt to run a 400 at 100% sprint effort from the very start. 

                             

                            Uphill  Big grin

                            "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

                             


                            HobbyJogger & HobbyRacer

                              ...

                               

                              I didn't say to run a time trial -- I said to attempt to run a 400 at 100% sprint effort from the very start. Sure, you'll blow up, but you will learn about the burn.

                               

                              If I did that, it would feel like uphill, if not worse, by the 300 point I think.

                              It's a 5k. It hurt like hell...then I tried to pick it up. The end.


                              Hawt and sexy

                                I'm sure I've read somewhere that the older you get the less likely you are to feel that burn but I'm darned if I can find the quote. A bit like some elderly people that get fractures (neck of femur) without any apparent pain symptoms involved - seen that in someone myself. As we are both "of a certain age" Simon that might well be one explanation. Certainly I get leg soreness after big efforts but I don't recall that severe burn of my youth.

                                This is a comet topic in the LHR fourm. Your experience is not unique. My theory is the old heart that has had years of training just cannot beat as fast to bring this feeling about. You have trained to the point where your heart is super fit and just does not go up into that top range anymore. I am starting to run into this a tiny bit, but not as extreme as some other peeps 20+ years my elder. And I have the disclaimer that I do not have that soft science background, so my thoughts might be skewed.

                                 

                                I did have a professor in  college that was in her 50s when she broke her arm playing volleyball. It was a week before she found out it was broken. She just said that it didn't hurt enough for her to consider being broken. She just showed up to class one day with her arm in a brace and her story.

                                 

                                Is it possible that as we age and deal with more pain we desensitize ourselves somewhat? I know any pain I have, I relate it to some other pain I might have had in life and set my perception of the current pain based on these comparisons. If everyone does that I could see how that might dilute the waters somewhat.

                                I'm touching your pants.

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