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Why is sprinting on low carb okay but running may be problematik?

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  • Why is sprinting on low carb okay but running may be problematik?

    From what I understand, sprinting at high effort for a short amount of time burns pure gluccose while the average runner burns partly fat/partly sugar. Why is sprinting recommended while eating (very) low carb as it seems to empty glycogen stores quickly (as well as strength or interval training that is primal as well)? Isn`t there reason to refill the stores after those types of exercises? I do not fully understand the science. Could anyone give me an explaination?
    Thank you!

  • #2
    I'm not totally sure. I think that if you're sprinting once a week or less, your body has ample time to recover glycogen stores via gluconeogensis. I could be totally wrong, but I think it takes longer to refill glycogen via gluconeogenesis versus glycogen synthesis from ingested glucose.

    Also, I believe the total amount of glycogen used in a sprint session is less than that used in a typical long, high-intensity jog. The faster you jog, the more glycogen you will be using, but it's always a mix of fuels. Maybe someone more educated than me can elucidate.

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    • #3
      Sprinting is pretty self-explanatory: run really, really fast in short bursts of output. Barring previous injury, we’re all built to sprint – which is why it’s a staple of Primal fitness. It builds both anaerobic and aerobic capacity while promoting growth hormone secretion, fat mobilization, and maximum power development. Simply put, if you want to build lean mass and burn body fat, sprinting at least once a week is the way to achieve both. Want proof? Just compare the bodies of your average sprinter and your average marathon runner. Which would you rather resemble?
      Primal Blueprint Workout Plan: The Basics | Mark's Daily Apple
      What Are Tabata Sprints? | Mark's Daily Apple

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      • #4
        Doesn't waste your muscle away and digs into a different glycogen storage area(fast twitch if done right). Pretty much sprint like your life depends on it.
        Last edited by pyro13g; 08-25-2011, 04:44 PM.

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        • #5
          If you do a search on google for "sprinting hormones" there's a lot of literature on the hormonal effects of sprinting, which seem to be the greatest benefit to me.
          Currently dabbling in: IF, leangains, Starting Strength, 5/3/1

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          • #6
            Distance running is supposed to burn your muscles for quick glycogen, leaving you with smaller and smaller muscles over time and eventually reducing your capacity to do much of anything else.

            I've also read that constant running elevates cortisol to the point of convincing your body it needs to store a lot of extra fat. This would be evolutionarily useful because if weird crap is going on in the world and you're running a long way to survive, the extra bit of blubber will do you well when you get to your new home and have to figure out what to eat. Good for Grok once or twice in a lifetime, bad for Korg to be doing consistently.

            But you've just got to wonder why the Tarahumara have such amazing legs. From the legends I've read and the endurance they maintain, they ought to look like floppy sheets of skin on wooden planks. For reference, here's a picture of a dumb white guy showing poor foot form alongside a real runner who knows how to use his feet.



            Maybe it's the corn beer?
            Crohn's, doing SCD

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            • #7
              Originally posted by pyro13g View Post
              Doesn't waste your muscle away and digs into a different glycogen storage area(fast twitch if done right). Pretty much sprint like your life depends on it.
              Not exactly how it works - there's no separate glycogen storage area for fast/slow twitch.

              Sprinting, if done correctly with sufficient recovery time in between sprints, basically uses two pathways - using immediate ATP reserves(these last only a few seconds), and burning glucose for energy. You're tapping what's immediately available, and the efforts are short enough that energy stores generally aren't challenged.

              Distance running tends to be a hybrid of glucose/glycogen and fat burning: the body will actually utilize both pathways to meet energy needs, depending on intensity and duration, with fat being the dominant fuel at lower intensities and glucose/glycogen burning supplementing it at higher intensities. But when the body can't tap enough glucose/glycogen, it will supplement that with some protein burning - which is where muscle breakdown can occur. Typically this occurs with longer efforts. I know if I go 45+ minutes with enough intensity I can smell a bit of ammonia on my breath - which is an indication of protein burning.

              In general if you keep the effort short enough(like sprinting), or low enough in intensity for longer activities, you'll avoid the protein/muscle burning scenario. This is exactly what PBF advocates - lots of moving "slowly", and occasional sprinting. These days I try to cap hard cardio efforts at 30 minutes, which seems to keep me out of the protein-burning regime.
              Last edited by jsa23; 08-27-2011, 05:04 AM.

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              • #8
                Originally posted by jsa23 View Post
                not exactly how it works - there's no separate glycogen storage area for fast/slow twitch.
                lol! it's stored right within the muscle cell for local needs and cannot be released into the bloodstream.
                Last edited by pyro13g; 08-28-2011, 05:24 AM.

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                • #9
                  Once your glycogen stores run out, your body cannot efficiently turn fat into energy while in an aerobic state. As fat cannot be directly converted into glucose, your body breaks down amino acids for energy. That means you burn lean muscle mass when you do aerobics. In a typical aerobics session, you burn more lean muscle mass than you burn fat.

                  On the other hand, sprinting is lactic acid threshold. It's like lifting weights. You secrete lots of HGH, too. You not only preserve muscle, but you may build it as well. Sprinting is anabolic. Running is catabolic. Sprinting makes you strong and lean. Running makes you weak and soft.

                  No animal on Earth does aerobics. They either travel slowly for large distances or sprint as hard as they can in short bursts to catch prey/run from predators. We're not made to do it. It's unnatural AND it's bad for your heart. Could you imagine the muscle damage you'd create if you held a barbell with 200 pounds on it above your chest for 30 minutes? Would you try and get strong that way? You'd create all kinds of injuries and see nothing positive. Well, your heart is a muscle just like your chest muscles. You make it stronger by heavy repetitions - bring your heart rate up very high for a short duration, bring it down for a short duration, repeat, just like lifting weights. That's what sprints do. When you hold your heart at a high rate for a long period like you would doing aerobic cardio, you're hurting yourself. Your heart wasn't designed for that kind of stress.
                  Last edited by ChocoTaco369; 08-28-2011, 05:46 AM.
                  Don't put your trust in anyone on this forum, including me. You are the key to your own success.

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                  • #10
                    Originally posted by jsa23 View Post
                    Distance running tends to be a hybrid of glucose/glycogen and fat burning: the body will actually utilize both pathways to meet energy needs, depending on intensity and duration, with fat being the dominant fuel at lower intensities and glucose/glycogen burning supplementing it at higher intensities. But when the body can't tap enough glucose/glycogen, it will supplement that with some protein burning - which is where muscle breakdown can occur. Typically this occurs with longer efforts. I know if I go 45+ minutes with enough intensity I can smell a bit of ammonia on my breath - which is an indication of protein burning.

                    In general if you keep the effort short enough(like sprinting), or low enough in intensity for longer activities, you'll avoid the protein/muscle burning scenario. This is exactly what PBF advocates - lots of moving "slowly", and occasional sprinting. These days I try to cap hard cardio efforts at 30 minutes, which seems to keep me out of the protein-burning regime.
                    Great info! I recently ran my first (and only) marathon and boy, am I glad that training is over. Now, I'm trying to figure out a way to continue running, but at an intensity low enough to be burning mostly fat while keeping cortisol as low as possible. I still want the cardio benefits for the ole heart and lungs, of course - not to mention my brain, as running is free therapy for me. (I'll also be sprinting once a week just as soon as it's not 75 degrees with 55% humidity at 5am here) I'm wondering how to get the best bang for my buck out of my runs - a 4 mile jog/run at a moderate pace has been what I've been doing 4 times a week, but I'm wondering if I should even trim them down to 3 mile runs here and there.

                    Any recommendations? (I also do Pilates, some weights and lots of body weight "stuff" consistently) I'm basically trying to find a happy place where I'm getting the good stuff without the bad - trying to tweak distance and speed to get there....
                    Last edited by GoJenGo; 08-28-2011, 06:39 AM.
                    Life is not a matter of having good cards, but of playing a poor hand well.

                    - Robert Louis Stevenson

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                    • #11
                      Originally posted by ChocoTaco369 View Post
                      Once your glycogen stores run out, your body cannot efficiently turn fat into energy while in an aerobic state. As fat cannot be directly converted into glucose, your body breaks down amino acids for energy. That means you burn lean muscle mass when you do aerobics. In a typical aerobics session, you burn more lean muscle mass than you burn fat.

                      On the other hand, sprinting is lactic acid threshold. It's like lifting weights. You secrete lots of HGH, too. You not only preserve muscle, but you may build it as well. Sprinting is anabolic. Running is catabolic. Sprinting makes you strong and lean. Running makes you weak and soft.

                      No animal on Earth does aerobics. They either travel slowly for large distances or sprint as hard as they can in short bursts to catch prey/run from predators. We're not made to do it. It's unnatural AND it's bad for your heart. Could you imagine the muscle damage you'd create if you held a barbell with 200 pounds on it above your chest for 30 minutes? Would you try and get strong that way? You'd create all kinds of injuries and see nothing positive. Well, your heart is a muscle just like your chest muscles. You make it stronger by heavy repetitions - bring your heart rate up very high for a short duration, bring it down for a short duration, repeat, just like lifting weights. That's what sprints do. When you hold your heart at a high rate for a long period like you would doing aerobic cardio, you're hurting yourself. Your heart wasn't designed for that kind of stress.
                      There is a certain logic there. Good analogy.
                      http://rolfdevinci.blogspot.com/

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                      • #12
                        Originally posted by pyro13g View Post
                        lol! it's stored right within the muscle cell for local needs and cannot be released into the bloodstream.
                        And there's no such thing as exercise that engages only "slow-twitch" or "fast-twitch" muscles while the others sit around idly, which makes the above irrelevant. The entire muscle is being engaged and burning its stores simultaneously, and this may be supplemented by the release of stored glycogen from the liver.

                        Originally posted by ChocoTaco369
                        Once your glycogen stores run out, your body cannot efficiently turn fat into energy while in an aerobic state. As fat cannot be directly converted into glucose, your body breaks down amino acids for energy. That means you burn lean muscle mass when you do aerobics. In a typical aerobics session, you burn more lean muscle mass than you burn fat.
                        Minor point of clarification here: protein burning - as indicated by an ammonia-like smell on one's breath - begins long before glycogen reserves are exhausted. A conditioned, but non-elite marathon runner often has enough glycogen reserves between muscles and the liver that he can often avoid "hitting the wall"(exhausting glycogen reserves) until somewhere in the 15-21 mile range. A hard effort at 1/3 that distance or so - maybe less - and you're already starting to burn protein.

                        Protein breakdown for energy tends to supplement other energy pathways rather than merely taking over when they are exhausted - and hence is a problem even if you have more than enough glycogen reserves for what you're doing.
                        Last edited by jsa23; 08-28-2011, 01:21 PM.

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