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Glycogen storing capacity

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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xristos

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Sep 5, 2013
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Is increased glycogen storing capacity useful enough adaptation to pursue for a freediver over other things?
 

7BDiver

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Sep 5, 2019
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I don't feel other pursuits would necessarily need to be sacrificed, anaerobic exercise, short high intensity and lifting likely develop robust glycogen storing capacity for a generally fit person. Prolonged endurance exercise is needed to significantly deplete glycogen. The nice thing about increased glycogen is the reduced muscle deterioration in anaerobic exercise and more energy at hand when ATP runs low. At least with diving where there is intermittent recovery the replenishing oxygen will convert the lactic acid back to glycogen readily. Another consideration is that someone with high glycogen in the muscles at rest will have more oxygen uptake compared to someone with low glycogen as more synthesis of glycogen from lactic acid will be taking place. Food with high glycemic index will build glycogen prior to exercise and caffeine is known to help restore glycogen stores considerably hours after.
 
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MarcinB

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Oct 26, 2012
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It depends on the type of of diving. If we're talking about the performance in one maximal dive, average glycogen stores should be perfectly enough. There's no chance that they are reduced in significant amount during a single dive, no matter how long it is. Things are, however, different in the case of long diving sessions (e.g. spearfishing). Large glycogen stores are very important here to prevent hypoglycemia and provide energy for muscles. When your glycogen stores are depleted muscles become fatigued quicker and your body is forced to use mostly fatty acids as a source of energy which may increase the risk of BO.
 
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7BDiver

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Muscles do not immediately transition from using ATP to breakdown of glycogen during anaerobic exercise. During high intensity exercise, anaerobic capacity (i.e. the amount of ATP that can be produced) is determined by the muscle content of phosphocreatine (PCr), the buffer capacity and the volume of the contracting muscle mass. The maximal rate of ATP supply from PCr is higher than that from glycolysis and, during the first 3 s of contraction, PCr breakdown contributes to 70 % of the ATP formation. Creatine loading/dietary supplementing will help increase PCr content, muscle mass will increase capacity and both will increase anaerobic capacity.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4213384/

Furthermore, outside of just muscle demand for ATP the brain can greatly benefit from phosphocreatine as it may markedly reduce neuronal loss and improve motor function during hypoxia. The study below shows at least the short duration benefits but longer duration hypoxia testing was not assessed.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4478245/
 

xristos

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Another consideration is that someone with high glycogen in the muscles at rest will have more oxygen uptake compared to someone with low glycogen as more synthesis of glycogen from lactic acid will be taking place.
Indeed creatine supplementation is something i will employ in this year plan. Im currently researching the specifics of it but lets not go off topic there is another thread on this specific subject. Im not sure i understand what the quoted sentence means to us. Like if you have big glycogen storing capacity you will have more tedious time recovering from sessions with lots of muscle acidity?
 

7BDiver

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Quite right, back to the original question, what will determine if one is going to dominantly use glycogen in an anaerobic metabolism or fatty acids in aerobic metabolism? Everyone will start out movement in the anaerobic state regardless of athletic fitness due to circulatory lag. Depending on VO2 max/threshold anaerobic metabolism will last approximately 90 seconds for higher intensity exercise. If there is good cardiovascular fitness a transition to aerobic metabolism will take place earlier if O2 is sufficient and exertion is low, this is 15X more efficient that glycolysis. The tradeoff is with aerobic metabolism the heart rate will be low and steady with more efficient use of energy but more oxygen is consumed during the dive. Anaerobic metabolism is less efficient but much faster and will increase heart rate throughout exertion not requiring O2. Upon recovery oxygen uptake may be 40% higher but glycogen synthesis is very quick. One may go so far as to choose a fitness regimen to tailor what metabolism will be dominant based on body type biased to Type 1 or Type 2 muscles.
 

7BDiver

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I was thinking about how to experiment or test what metabolism gives better performance for an individual. If one does a high intensity apnea walk and a low intensity walk they could measure final heart rate and oxygen concentration. This may reveal what state the metabolism was in. Distance may reveal which metabolism is favorable to the fitness type. Climbing heart rate and less oxygen consumption may indicate anaerobic state. If heart rate levels of it may indicate a period of aerobic metabolism. I am left scratching my head finding out how O2/CO2 ratio or O2 concentration affects the metabolism.
 

xristos

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Sep 5, 2013
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As i view it, anaerobic glycolysis is clearly the desired energy pathway. Is it possible to have best of both worlds, not forced fast dive and anaerobic glycolysis? The question is what training can help us achieve the highest possible percentage of energy produced this way. If you watch mateusz Malina 5 16 minute dive on YouTube he commentates that he gets vasoconstriction (itchy leg) super early like first turn . If it is strong enough it could mean anaerobic glycolysis?

There are depth discipline divers that sprint the first strokes shooting of the bottom plate, I think this is done in an attempt to stimulate anaerobic glycolysis.

We are off topic again and i like it:cool:
 
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xristos

Well-Known Member
Sep 5, 2013
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I was thinking about how to experiment or test what metabolism gives better performance for an individual. If one does a high intensity apnea walk and a low intensity walk they could measure final heart rate and oxygen concentration. This may reveal what state the metabolism was in. Distance may reveal which metabolism is favorable to the fitness type. Climbing heart rate and less oxygen consumption may indicate anaerobic state. If heart rate levels of it may indicate a period of aerobic metabolism. I am left scratching my head finding out how O2/CO2 ratio or O2 concentration affects the metabolism.
High Co2 means increased oxygenation of the muscle tissue ( oxygen disassosiation curve ) causing aerobic glycolysis? Thats my idea maybe wrong.
Going fast in water is too inefficient to compare with running through air. Need other experiment !
 
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7BDiver

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In general one must be at the upper limit of VO2 max or higher exertion in order to maintain anaerobic metabolism which is not practical prolonged. Muscle tissue in general has greater perfusion than is required, oxygen to the muscles is not limited by blood flow but by the ventilatory threshold in which blood can be oxygenated by cardiovascular endurance. Once exertion is reduced and aerobic metabolism becomes dominant O2 is used for energy production and conversion of lactate at least as fast as it is produced. However, with limited O2 for lactate conversion elevation in blood lactate concentration inhibits lipolysis and the metabolism will favor usage of carbohydrates from glycogen. I would imagine peripheral vasoconstriction through the dive reflex may be critical in maintaining anaerobic metabolism in the muscles. Similarly, poorly perfused tissue undergoing anaerobic metabolism may not mobilize lactate into the bloodstream until perfusion improves, with the rise of blood lactate level occurring after restoration of an adequate systemic blood flow. This is notable in seals as they do not release lactic acid into the blood stream until they resurface.
 

7BDiver

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To answer your question, if I were to train form maximum glycogen usage I would do a couple things: Anaerobic exercise and weight training to increase glycogen storage and uptake, and practice/improve dive response for best peripheral vasoconstriction effect. I wonder if DNF is intuitive to anaerobic metabolism since the exercise starts out and is maintained in short bursts of energy.
 
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xristos

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Sep 5, 2013
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To answer your question, if I were to train form maximum glycogen usage I would do a couple things: Anaerobic exercise and weight training to increase glycogen storage and uptake, and practice/improve dive response for best peripheral vasoconstriction effect. I wonder if DNF is intuitive to anaerobic metabolism since the exercise starts out and is maintained in short bursts of energy.
Wow... That, even if it's not the case is a spectacular concept! You think it is true that doing say a cnf dive with strong stroke and then mini glide, compared to steady continuous strokes(both scenarios with the same work rate for the same duration) employ different energy systems? Hats off for the idea!

It comes with its disadvantages, like the decelerations and burst s are inefficient meaning you will have to put out more joules of energy.

You will use atp cp system? Does it have the ability to replenish stores during a dive? I dont see why this could happen only in dnf.
 

7BDiver

Active Member
Sep 5, 2019
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Replenishing stores of glycogen or processing of lactate would not be restricted to any exercise, unless there is significant vasoconstriction O2 will be consumed to maintain lactate below a certain threshold under normoxia. I have seen divers using monofins using the kick and glide technique, I'm sure it has its place in all disciplines. Seals like to do a lot if kicking with extended glides but they are little torpedoes and still have some measure of aerobic metabolism having different oxygenation methods. When I figure out a good method of implementing the ideas I will certainly test the potential and performance!
 

7BDiver

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These are the most effective ways to stimulate the DR: Decreasing oxygen tension with Rv statics will potentiate the diving reflex and would be practical for short dives or where decreasing buoyancy is desired. Exercising or breath holding before immersion. Increasing vagal tone by being in the right mood. Being distracted or having poor mood has a profound effect and can completely inhibit bradycardia despite other stimulus. Apnea alone can stimulate the DR but is significantly improved when coupled with cold water/air on the face. Being healthy and exercising will increase vagal tone and make the DR more effective and easier to elicit. Exercising and psychological training are the best attributes to train as they will improve physiological responses that are not just an inherent reaction.
 

SDS

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Feb 16, 2018
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I agree with MarcinB. For a single max dive, muscle glycogen concentrations are not likely to be fully depleted. Do make sure you are not already depleted before your dive of course. Long sessions of repetitive diving such as during spearfishing may benefit from carboloading (glycogen supercompensation). However, glucose replenishment (drinks, bars) during the session shouldn’t be an issue, making carboloading not a worthwhile intervention imho.

Carboloading does not require a 7-day period of strict dietary guidelines (~old school); glycogen supercompensation can be reached within 24-48 h, by eating ~10 g of carbs per kg bodyweight per day after your final (strenuous) training session. It is likely that this means a change in your usual dietary pattern, and it contrasts to the tendency to eat less in the run up to (static) apnea performance. You can still experiment with it, but don’t do that during competition, experiment during the training phase. Don’t be alarmed that you suddenly gained 1-2 kg (= glycogen + water), it means that your intervention worked.

@7BDiver: some assumptions you make may benefit from a bit of nuance. I hesitated a bit to post this, but here is my interpretation on some of your ideas which may stimulate further speculation.
  • ‘anaerobic exercise, short high intensity and lifting likely develop robust glycogen storing capacity for a generally fit person.’ --> Also without regular implementation of this type of training one can increase glycogen stores (see above).
  • ‘At least with diving where there is intermittent recovery the replenishing oxygen will convert the lactic acid back to glycogen readily.’ --> But not in the working (contracting) muscles within that session.
  • ‘someone with high glycogen in the muscles at rest will have more oxygen uptake compared to someone with low glycogen as more synthesis of glycogen from lactic acid will be taking place’ --> This is incorrect (‘uptake’ is not ideal wording here!), but I assume that you are referring to the fact that energy production from glycogen is more oxygen-efficient compared to energy production from fatty acids – hence requiring less oxygen for a similar amount of work.
  • 'caffeine is known to help restore glycogen stores considerably hours after.' --> I am with you for the sake of good coffee, but it should not be considered a necessity to accomplish glycogen supercompensation.
  • Agreed that creatine monohydrate supplementation may be worthy to experiment with, either during the preparatory phase to enable a greater training load (strength training, HIT), and potentially during the competitive phase to compete with a slightly elevated anaerobic alactic capacity. Again, don’t be surprised gaining some weigth within the first week of supplementation. Unfortunately, this is due to fluid retention, not sudden gain in muscle mass.
  • Hmm, should one train ‘according to’ his/her fiber type composition (and associated ‘metabolic preferences’), or should one train according to the required energy systems for the sport/discipline of his/her choosing? Imho, specificity is key here.
  • I expect your heart rate during apnea walks (hope it will decrease, not increase!) to give you some information about your dive response rather than anything else.
  • ‘Muscle tissue in general has greater perfusion than is required, oxygen to the muscles is not limited by blood flow but by the ventilatory threshold in which blood can be oxygenated by cardiovascular endurance.’ --> This is not correct. The limiting factor of whole body VO2peak in healthy individuals is oxygen delivery (cardiac output and total hemoglobin mass), thus including muscle perfusion! Only when using small muscle mass (i.e., single-leg cycling) oxygen delivery (through perfusion) exceeds muscle oxygen combustion capacity.
  • ‘I wonder if DNF is intuitive to anaerobic metabolism since the exercise starts out and is maintained in short bursts of energy.’ --> During repetitive short bouts of muscle contraction, metabolism gradually shifts from anaerobic to aerobic pathways. I.e., a single 30 s sprint: PCr, anaerobic glycolysis, and aerobic glycolysis contribute approximately 16, 55, and 29% of the energy contribution. Perform 3 of these sprints, with 4 min of recovery in between, the relative energy contribution during the last sprint will have shifted to 16, 21, and 63%. Similar shifts occus during shorter (i.e. 6-s, 30-s recovery) repeated sprints. However, freediving is not an all-out performance energy-wise, making it far more more complex to estimate what would be going on. I keep hearing people saying that the initial part is very anaerobic, I doubt that - it is not an all-out performance - is it? (or you should seriously work on your duck dive and hydrodynamics). I presume the greatest rate in lactate generation will occur during the ascent, when your muscles have to work hard though they are not being well-perfused due to vasoconstriction.
 
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xristos

Well-Known Member
Sep 5, 2013
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I agree with MarcinB. For a single max dive, muscle glycogen concentrations are not likely to be fully depleted. Do make sure you are not already depleted before your dive of course. Long sessions of repetitive diving such as during spearfishing may benefit from carboloading (glycogen supercompensation). However, glucose replenishment (drinks, bars) during the session shouldn’t be an issue, making carboloading not a worthwhile intervention imho.

Carboloading does not require a 7-day period of strict dietary guidelines (~old school); glycogen supercompensation can be reached within 24-48 h, by eating ~10 g of carbs per kg bodyweight per day after your final (strenuous) training session. It is likely that this means a change in your usual dietary pattern, and it contrasts to the tendency to eat less in the run up to (static) apnea performance. You can still experiment with it, but don’t do that during competition, experiment during the training phase. Don’t be alarmed that you suddenly gained 1-2 kg (= glycogen + water), it means that your intervention worked.

@7BDiver: some assumptions you make may benefit from a bit of nuance. I hesitated a bit to post this, but here is my interpretation on some of your ideas which may stimulate further speculation.
  • ‘anaerobic exercise, short high intensity and lifting likely develop robust glycogen storing capacity for a generally fit person.’ --> Also without regular implementation of this type of training one can increase glycogen stores (see above).
  • ‘At least with diving where there is intermittent recovery the replenishing oxygen will convert the lactic acid back to glycogen readily.’ --> But not in the working (contracting) muscles within that session.
  • ‘someone with high glycogen in the muscles at rest will have more oxygen uptake compared to someone with low glycogen as more synthesis of glycogen from lactic acid will be taking place’ --> This is incorrect (‘uptake’ is not ideal wording here!), but I assume that you are referring to the fact that energy production from glycogen is more oxygen-efficient compared to energy production from fatty acids – hence requiring less oxygen for a similar amount of work.
  • 'caffeine is known to help restore glycogen stores considerably hours after.' --> I am with you for the sake of good coffee, but it should not be considered a necessity to accomplish glycogen supercompensation.
  • Agreed that creatine monohydrate supplementation may be worthy to experiment with, either during the preparatory phase to enable a greater training load (strength training, HIT), and potentially during the competitive phase to compete with a slightly elevated anaerobic alactic capacity. Again, don’t be surprised gaining some weigth within the first week of supplementation. Unfortunately, this is due to fluid retention, not sudden gain in muscle mass.
  • Hmm, should one train ‘according to’ his/her fiber type composition (and associated ‘metabolic preferences’), or should one train according to the required energy systems for the sport/discipline of his/her choosing? Imho, specificity is key here.
  • I expect your heart rate during apnea walks (hope it will decrease, not increase!) to give you some information about your dive response rather than anything else.
  • ‘Muscle tissue in general has greater perfusion than is required, oxygen to the muscles is not limited by blood flow but by the ventilatory threshold in which blood can be oxygenated by cardiovascular endurance.’ --> This is not correct. The limiting factor of whole body VO2peak in healthy individuals is oxygen delivery (cardiac output and total hemoglobin mass), thus including muscle perfusion! Only when using small muscle mass (i.e., single-leg cycling) oxygen delivery (through perfusion) exceeds muscle oxygen combustion capacity.
  • ‘I wonder if DNF is intuitive to anaerobic metabolism since the exercise starts out and is maintained in short bursts of energy.’ --> During repetitive short bouts of muscle contraction, metabolism gradually shifts from anaerobic to aerobic pathways. I.e., a single 30 s sprint: PCr, anaerobic glycolysis, and aerobic glycolysis contribute approximately 16, 55, and 29% of the energy contribution. Perform 3 of these sprints, with 4 min of recovery in between, the relative energy contribution during the last sprint will have shifted to 16, 21, and 63%. Similar shifts occus during shorter (i.e. 6-s, 30-s recovery) repeated sprints. However, freediving is not an all-out performance energy-wise, making it far more more complex to estimate what would be going on. I keep hearing people saying that the initial part is very anaerobic, I doubt that - it is not an all-out performance - is it? (or you should seriously work on your duck dive and hydrodynamics). I presume the greatest rate in lactate generation will occur during the ascent, when your muscles have to work hard though they are not being well-perfused due to vasoconstriction.
That's a nice well written summary, shared, learned and corrected old knowledge but mainly many new questions came up.

I want to add the obvious that you can raise glycogen storing capacity by endurance training zone 1 in 3 zone system or 50-60% of max heart rate for increasing durations.
 

7BDiver

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Sep 5, 2019
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SDS, thank you for questioning much of the statements, as I read studies I will inevitably mix something up and get it wrong.

Yes, glycogen stores and availability are determined by diet, however, capacity is dependent upon muscle mass. As far as I know glycogen concentration in the muscles is not determined by exercise.

To add a little clarification: The fate of the lactate produced is primarily oxidative (55–70%), with as much as 90% of the labeled carbon in tracer lactate showing up as CO2 during active recovery from exercise. Lactate clearance during rest and exercise occurs primarily by three processes: oxidation (50% to 80%), gluconeogenesis/glyconeogenesis (10% to 25%), and transamination (5% to 10%). All three processes involve the movement of lactate. Instead of using the word "uptake", it would have been better to state that there will be a greater oxygen debt from anaerobic metabolism required to process lactate once respiration is restored.

Caffeine is not required for supercompensation, it merely speeds up the recovery of glycogen stores given the other dietary requirements have been met.

If you get a dive response during apnea walk your heart rate would decrease. I would be incorrect stating a raise in HR is indicative of anaerobic metabolism, it is more likely be a response to stress or dehydration.

Perhaps better stated: At maximum O2 uptake, O2 supply to muscle is always limited by both perfusion and diffusion. In nomoxia, perfusion limitation is prevalent, but in hypoxia diffusion limitation becomes predominant. In diffusion-limited gas exchange, the gas will diffuse as long as the partial pressure gradient is maintained. In perfusion-limited gas exchange, the partial pressure gradient is not maintained and blood flow must be increased in order to increase the amount of gas transported. This is dynamic as muscle oxygen uptake and energy consumption increases with increasing muscle contraction frequency.

I agree with your final statement, no dive will be all out nor maintain anaerobic metabolism. It will start out anaerobic regardless of effort and likely last a minute before transitioning to a mostly aerobic state. As stated before, the immediate stores of ATP from aerobic metabolism is very short lived, anaerobic metabolism is always present at the start of an exercise until HR, circulation and aerobic metabolism catch up to the ATP demand. I think the main question for the topic at hand is how to prolong the anaerobic state, preferably without increasing exertion outside of being practical, and is this of significant benefit to reserving oxygen for vital organs? How long can one expect anaerobic metabolism to last before the after effects decrease performance?
 

xristos

Well-Known Member
Sep 5, 2013
157
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SDS, thank you for questioning much of the statements, as I read studies I will inevitably mix something up and get it wrong.

Yes, glycogen stores and availability are determined by diet, however, capacity is dependent upon muscle mass. As far as I know glycogen concentration in the muscles is not determined by exercise.

To add a little clarification: The fate of the lactate produced is primarily oxidative (55–70%), with as much as 90% of the labeled carbon in tracer lactate showing up as CO2 during active recovery from exercise. Lactate clearance during rest and exercise occurs primarily by three processes: oxidation (50% to 80%), gluconeogenesis/glyconeogenesis (10% to 25%), and transamination (5% to 10%). All three processes involve the movement of lactate. Instead of using the word "uptake", it would have been better to state that there will be a greater oxygen debt from anaerobic metabolism required to process lactate once respiration is restored.

Caffeine is not required for supercompensation, it merely speeds up the recovery of glycogen stores given the other dietary requirements have been met.

If you get a dive response during apnea walk your heart rate would decrease. I would be incorrect stating a raise in HR is indicative of anaerobic metabolism, it is more likely be a response to stress or dehydration.

Perhaps better stated: At maximum O2 uptake, O2 supply to muscle is always limited by both perfusion and diffusion. In nomoxia, perfusion limitation is prevalent, but in hypoxia diffusion limitation becomes predominant. In diffusion-limited gas exchange, the gas will diffuse as long as the partial pressure gradient is maintained. In perfusion-limited gas exchange, the partial pressure gradient is not maintained and blood flow must be increased in order to increase the amount of gas transported. This is dynamic as muscle oxygen uptake and energy consumption increases with increasing muscle contraction frequency.

I agree with your final statement, no dive will be all out nor maintain anaerobic metabolism. It will start out anaerobic regardless of effort and likely last a minute before transitioning to a mostly aerobic state. As stated before, the immediate stores of ATP from aerobic metabolism is very short lived, anaerobic metabolism is always present at the start of an exercise until HR, circulation and aerobic metabolism catch up to the ATP demand. I think the main question for the topic at hand is how to prolong the anaerobic state, preferably without increasing exertion outside of being practical, and is this of significant benefit to reserving oxygen for vital organs? How long can one expect anaerobic metabolism to last before the after effects decrease performance?
Local lactate use depends on exercise exertion. During rest, approximately 50% of lactate disposal take place through lactate oxidation whereas in time of strenuous exercise (50-75% VO2 max) approximately 75-80% of lactate is used by the active cell, indicating lactate’s role as a major contributor to energy conversion during increased exercise exertion.
 
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