There are a few errors. VT1 is the 'ventilatory threshold' and oxygen uptake will start to deviate from CO2 exhalation. The VT2 is called the respiratory compensation point. This is most easily visualised by the 'ventilatory threshold', where VE/VCO2 will drop, then flatten out (isocapnic) between the VT1 and VT2 and then increase again due to hyperventilation past the respiratory compensation point. Respiratory compensation is not a compensation to elevated CO2, but lowered pH and actually leads to a relative hypocapnia. The anerobic threshold is associated with, but should not be considered synonymous with either threshold, since this is more of a peripheral phenomena, depending on the relative metabolic balance of the respective motor units and their activation. Likewise the lactate threshold isn't of key importance, because it is the large increase in the rate of glycolysis, rather than the accumulation of lactate that causes acidosis and there are various buffering mechanisms. (Remember that lactic acid is less acidic than pyruvic acid and pyruvate from glycolysis is an input to the citric acid cycle and consequently oxidative phosphorylation).
Great video. Information is extremely helpful with my studies for my final exam in Ex. Phys. The video reinforces the lecture materials that I received in class.
Question for you Doctor Sandoo. If caffeine can increase heart rate, does this mean caffeine puts you closer to VT2, assuming VT2 occurs at a given heart rate ???
thank you for explanation! Ive been doing a course and they did not explained properly many things, you gave it a great form and explanation on example, I really like it :)!
Thanks Ivica for this positive comment. The whiteboard helps to make presenting the information easier - I am pleased the video was useful to you. All the best in your studies!
Min 7:50 "CO2 increases dramatically due to (it) being a byproduct of glycolysis" My textbook or any online sources doesn't state CO2 as a byproduct of anaerobic glycolysis. Can anyone confirm?
Thanks Abishek! I will hopefully film more videos in the next couple of weeks and will upload them straight away. Keep a look out for them and thank you for your patience!
Hello Dr Aamer, Thanks for this elaborate video. I am interested in knowing about the fatty acid metabolism occurring concurrently with glucose oxidation, which is also generating acetyl-CoA and ketones at extremes of exercise. Please offer your expert comments. Regards Dr Suresh Shinde, MD.
Very nice video that put all together, congrats. Now the big question is: can you sustain a prolonged effort at vt2 speed, HR, power if you reach LT2 before you are reaching VT2?
Hello Dr. Sandoo, thank you for this wonderful video! As you probably know, there are different theories about these thresholds,; whether they are occurring at the same instance or not. From what I listened from other academics like yourself; it seems like there isn't any consensus about when these thresholds happen. Some lecturers and studies suggest that the lactate threshold occurs at the same time as the aerobic threshold occurs, immediately when anaerobic metabolism kicks in. Therefore, Ventilatory and Anaerobic thresholds occur at the same instance; after the aerobic and lactate threshold, when anaerobic glycolysis becomes the dominant energy source. What are your thoughts about this situation? Thank you very much!
I actually wrote an article on this topic for ACSM. This should help answer some of your queries and give you my perspectives on this measure. It can be found here: journals.lww.com/acsm-healthfitness/Fulltext/2021/05000/A_Brief_History_of_the_Anaerobic_Threshold_Concept.5.aspx
Excellent. However @ VT1 Glycolysis can proceed oxidatively when pyruvate is adequately cleared (used as fuel) through Type 1 fiber mitochondria vs,. the cytosol. Cytosolic metabolism of excess pyruvate would be anaerobic. This I assume is a consequence of exercise intensity vs., level of fitness. Thank you for the video.
Is glycolysis only major source of ATP in moderate intensity exercise? Or does oxdiation phosphate work together with glycolysis to make ATP in that period. I've got wondered what is difference between glycolysis in Moderate intensity and High intensity. Thank you for the video!
Great Video ! Otherwise, could you please explain how can we determine VT1 and VT2 through respiratory equivalents ? Is it true that VT1 corresponds to the first increase of VE/VO2 ratio with no concomitant change in VE/VCO2 ratio, while VT2 corresponds to the second increase of VE/VO2 ratio with a concomitant change in VE/VCO2 ratio ? Thanks in advance
For ease of use and interpretation, using HR training zones is the most effective way to ensure you are training in the desired intensity to elicit physiological adaptations. Further, knowing the HR achieved at your LT will provide the specificity needed in your training.
I am a big fan of "test, don't guess". However, I can go to many labs in my area and get VT2/lactate...however...VT1 seems to be elusive; at least in Milwaukee Wisconsin. Any recommendation on how to deal with this or I am misunderstanding the services they advertise?
My suggestion would be to visit your nearest University Sport Science department, as they will have lab staff who can interpret the data correctly and provide you more specific information. It would be even better if they offer such service to the public (e.g. human performance) as they will be confident in interpreting the data to exactly how you need it.
Note that the the graph in the video is incorrect at VT1, where there should be a clear deviation in both the minute ventilation of Oxygen and Carbon Dioxide. By definition, if there is no deviation in ventilation, there is no ventilatory threshold. Any sports science laboratory that performs ramped maximal power output CPET tests will be able to supply the raw ventilation (VE), VO2 and VCO2 data, with which you can perform your own analysis using the "V‐Slope Method" or the ventilatory equivalent method to determine the VT1.
Thank you for the video, and a question: as a fairly novice runner, I’m (1) unable to run at all for more than a few minutes or half a mile to a mile without my HR exceeding 90% of max; (2) happen to be able to run overall (by average pace) *faster* with comparable or less perceived effort by taking brief (30-60s) walk breaks after every half a mile to a mile or so. How can I train to get to a point where I can just jog continuously and pleasantly (in zone 1 or 2) for a few miles? All the conventional running advice about logging in most of your mileage in easy pace in zone 1 or 2 feels unusable to me because just jogging gets me to zone 5 in a few minutes.
I have no medical qualifications at all, so big grain of salt: But I was where you describe in May. I just followed the “increase distance by no more than 10% per week” and set out to run those distances. I started with “giving” myself 5 miles. At first it was hard to run the full 5 in a week, running 4 times a week (1.25 each). Once I could do that I chose a day for my “long run” (most people chose a weekend day.) I would add my +10% distance on that day, trying to go further than I did before without stopping. At first that’s only like .1 or .2 a week. But pretty soon you’re adding a mile and get to the point you can run 1 hour without stopping. I worked my other runs up to how ever far I went in 15 minutes. Only once I was there did I really start to care about my heart rate. Pretty quickly I was able to run further at lower heart rates. I think at first we are just so weak there is nothing for it but to build up.
@@piedpiper1172 Thank you, that’s helpful to hear. I’ve been able to run for 45-60+ minutes for over 6 months now, but my HR still consistently hits 170+ (over 90% of max) in the first few minutes and then mostly stays at that high level. On rare occasions, it’s slightly lower, for example, on a really good day, I can hold a 167 or so average HR through a 10K distance, but that’s not the norm. Slowing down doesn’t really seem to help because below a certain speed, my form is so poor that it is uneconomical and therefore induces a high HR. What if anything did you do to reduce your HR once you did start caring about it as you say? Did just more and more running automatically bring it down? That is what doesn’t seem to be happening for me.
@@aroundandround Oh! I’m doing 3-4 miles 3 times a week and 5-6 one time now. Following a half marathon plan. I swap at least one of the shorter runs for low heart rate on the stationary. Most of my runs are in the low 160’s, which is only a little above my zone 2 max, spending about half the time in zone 2.
@@piedpiper1172 Ah cool, that’s about exactly my typical weekly mileage plan these days as well. Except my second mile onwards HR is usually 170+ (90% of my max HR of ~190). I’d be pretty happy if I could jog for even 30 mins at 160 as160 feels so much breezier than 170.
Having read the other comments I will just add. Slow down. Even if it's uneconomical you will get used to that also and you legs.and body will adjust. Just out curiosity are you overweight or what way would you describe yourself? Also one thing to note is if you are say the 167bpm you mention that doesn't matter really.that much unless compared to your max heart rate or VO2max. My max heart rate was 199 on a Vow max (it went higher in training ) and my lactic-threshold is just at 141. Yours could be 167 depends on the person. The guy who did my vow Mac said his and his brothers max heart rates are completely different. So comparing to others would be a bad idea. Good luck. If you doing that distance you can now Jog so you got there
There are a few errors. VT1 is the 'ventilatory threshold' and oxygen uptake will start to deviate from CO2 exhalation. The VT2 is called the respiratory compensation point.
This is most easily visualised by the 'ventilatory threshold', where VE/VCO2 will drop, then flatten out (isocapnic) between the VT1 and VT2 and then increase again due to hyperventilation past the respiratory compensation point. Respiratory compensation is not a compensation to elevated CO2, but lowered pH and actually leads to a relative hypocapnia.
The anerobic threshold is associated with, but should not be considered synonymous with either threshold, since this is more of a peripheral phenomena, depending on the relative metabolic balance of the respective motor units and their activation. Likewise the lactate threshold isn't of key importance, because it is the large increase in the rate of glycolysis, rather than the accumulation of lactate that causes acidosis and there are various buffering mechanisms. (Remember that lactic acid is less acidic than pyruvic acid and pyruvate from glycolysis is an input to the citric acid cycle and consequently oxidative phosphorylation).
Thanks! Very clear together with the video.
Where are we relative to Vo2 max at each threshold?
@@geronimojones2 Depends on the fitness of the individual. I think
thank you, that explains everything
so that means the red and blue lines should actually cross at VT2?
Glycolysis itself produces no CO2, it rather comes from HCO3-buffering lactate. Otherwise, great video! Thanks for making it.
Great point, and thanks for taking the time to share it.
Late response, but note that the end product of glycolysis is pyruvate, some of which enters the TCA cycle which does produce CO2.
Dr Sandoo, thank you so much for explaining this so clearly. Fantastic you tube channel. I am sports physiotherapist and this is so helpful 👍
You are very welcome and I am pleased the content is helpful in your studies.
Thanks for this video, it can be a very complicated topic, and you explained it very well, and made it easy to understand, cheers
Thanks Thomas - I am pleased the information came across well. I will continue to produce new videos using a similar approach.
Fascinating video, well presented. Thanks!
Thank you so much for putting all this information together in an easier to understand way than my textbook!
You're very welcome Cindy. Thanks for the comment, and all the best with your studies!
Thank you! everything is clear for me. Bless you.
Great video. Information is extremely helpful with my studies for my final exam in Ex. Phys. The video reinforces the lecture materials that I received in class.
Excellent - thanks Shelly for leaving this comment, I am pleased it was useful. Also, I hope your exam went well (or goes well if still to take it).
I just wanted to say "that's great!". Many thanks for posting it.
Thanks Dario. I am very happy the information was useful to you.
Great video, very well explained! Thank you!
Excellent video, thank you for this. You did a great job of explaining this to a person uneducated in the subject.
Thanks Michael. I am pleased it was useful in helping build your knowledge. All the best with your learning.
Excellent - very clear and thorough. Thank you!
Thank you for taking the time to leave this comment and the positive vibes!
great material ! thank You keep it up !
Question for you Doctor Sandoo. If caffeine can increase heart rate, does this mean caffeine puts you closer to VT2, assuming VT2 occurs at a given heart rate ???
Great explanation. I just started my journey towards a pt certification and this really helped expand my understanding of the material. Thank you!
Glad it was helpful! All the best with your certification.
Wow, thanks so much! This was a great refresher!
thank you for explanation! Ive been doing a course and they did not explained properly many things, you gave it a great form and explanation on example, I really like it :)!
Thanks Ivica for this positive comment. The whiteboard helps to make presenting the information easier - I am pleased the video was useful to you. All the best in your studies!
Thank you! This was very concise!
Thanks so much for such an informative and clear description. Many thanks - it really helped my understanding.
Thanks Chris for leaving this comment. I am pleased the video helped. All the best with your training and studying!
Min 7:50 "CO2 increases dramatically due to (it) being a byproduct of glycolysis" My textbook or any online sources doesn't state CO2 as a byproduct of anaerobic glycolysis. Can anyone confirm?
I have been waiting for so long, plz keep posting 👍
Thanks Abishek! I will hopefully film more videos in the next couple of weeks and will upload them straight away. Keep a look out for them and thank you for your patience!
Thank you, made very clear and easy to understand.
How does glycolysis produce CO2 when the 6 carbons are still in the 2 pyruvate or lactate molecules?
very well explained
Thanks Tina!
Great videos man, very helpful
Great video thanks for posting it!
Glad you enjoyed it!
this was so easy to understand! thank you
Glad it was helpful!
Hello Dr Aamer,
Thanks for this elaborate video. I am interested in knowing about the fatty acid metabolism occurring concurrently with glucose oxidation, which is also generating acetyl-CoA and ketones at extremes of exercise. Please offer your expert comments. Regards
Dr Suresh Shinde, MD.
Excellent explanation. Thanks so much!
You're very welcome!
Very nice video that put all together, congrats. Now the big question is: can you sustain a prolonged effort at vt2 speed, HR, power if you reach LT2 before you are reaching VT2?
Great job thanks
excellent video
if you are fat adapted like me for 3 yrs, will I have a higher lactate threshold?
Very helpful for a medical student drowning in final exams :)
All the best for your final exams Rachel!
Great explanation!! thank you
You are welcome!
As an ultra runner this is very helpful - thanks
Glad it was helpful!
Thank you so much Aamer!
My pleasure!
Hello Dr. Sandoo, thank you for this wonderful video!
As you probably know, there are different theories about these thresholds,; whether they are occurring at the same instance or not. From what I listened from other academics like yourself; it seems like there isn't any consensus about when these thresholds happen. Some lecturers and studies suggest that the lactate threshold occurs at the same time as the aerobic threshold occurs, immediately when anaerobic metabolism kicks in. Therefore, Ventilatory and Anaerobic thresholds occur at the same instance; after the aerobic and lactate threshold, when anaerobic glycolysis becomes the dominant energy source. What are your thoughts about this situation?
Thank you very much!
I actually wrote an article on this topic for ACSM. This should help answer some of your queries and give you my perspectives on this measure. It can be found here: journals.lww.com/acsm-healthfitness/Fulltext/2021/05000/A_Brief_History_of_the_Anaerobic_Threshold_Concept.5.aspx
Thanks so much really helpful
Glad it helped Jack!
Thank you so much sir.. u saved my day. I was stuck on this topic forever 😂😂
Happy to help!
Sir that was beautiful
Thank you kindly!
Excellent. However @ VT1 Glycolysis can proceed oxidatively when pyruvate is adequately cleared (used as fuel) through Type 1 fiber mitochondria vs,. the cytosol. Cytosolic metabolism of excess pyruvate would be anaerobic. This I assume is a consequence of exercise intensity vs., level of fitness. Thank you for the video.
رجاءا ترجمة المحاضرات ... 😘😘😘😘
Thank you verry much for this video!
You're very welcome!
Is glycolysis only major source of ATP in moderate intensity exercise? Or does oxdiation phosphate work together with glycolysis to make ATP in that period. I've got wondered what is difference between glycolysis in Moderate intensity and High intensity. Thank you for the video!
Great Video ! Otherwise, could you please explain how can we determine VT1 and VT2 through respiratory equivalents ?
Is it true that VT1 corresponds to the first increase of VE/VO2 ratio with no concomitant change in VE/VCO2 ratio, while VT2 corresponds to the second increase of VE/VO2 ratio with a concomitant change in VE/VCO2 ratio ?
Thanks in advance
So amazing.. thank you!!!
Great video, always heard VT2 as LTP if that is correct. What's the best way you've seen to identify this point for running?
Is MLSS the same as LT2?
What would you say is the most effective way to determine exercise intensity for an endurance athlete?
For ease of use and interpretation, using HR training zones is the most effective way to ensure you are training in the desired intensity to elicit physiological adaptations. Further, knowing the HR achieved at your LT will provide the specificity needed in your training.
Thank you
You're welcome
Glycolysis doesn't create CO2?!
No, it doesn't.
I am a big fan of "test, don't guess". However, I can go to many labs in my area and get VT2/lactate...however...VT1 seems to be elusive; at least in Milwaukee Wisconsin. Any recommendation on how to deal with this or I am misunderstanding the services they advertise?
My suggestion would be to visit your nearest University Sport Science department, as they will have lab staff who can interpret the data correctly and provide you more specific information. It would be even better if they offer such service to the public (e.g. human performance) as they will be confident in interpreting the data to exactly how you need it.
Note that the the graph in the video is incorrect at VT1, where there should be a clear deviation in both the minute ventilation of Oxygen and Carbon Dioxide. By definition, if there is no deviation in ventilation, there is no ventilatory threshold.
Any sports science laboratory that performs ramped maximal power output CPET tests will be able to supply the raw ventilation (VE), VO2 and VCO2 data, with which you can perform your own analysis using the "V‐Slope Method" or the ventilatory equivalent method to determine the VT1.
Thank you for the video, and a question: as a fairly novice runner, I’m (1) unable to run at all for more than a few minutes or half a mile to a mile without my HR exceeding 90% of max; (2) happen to be able to run overall (by average pace) *faster* with comparable or less perceived effort by taking brief (30-60s) walk breaks after every half a mile to a mile or so. How can I train to get to a point where I can just jog continuously and pleasantly (in zone 1 or 2) for a few miles?
All the conventional running advice about logging in most of your mileage in easy pace in zone 1 or 2 feels unusable to me because just jogging gets me to zone 5 in a few minutes.
I have no medical qualifications at all, so big grain of salt:
But I was where you describe in May. I just followed the “increase distance by no more than 10% per week” and set out to run those distances.
I started with “giving” myself 5 miles. At first it was hard to run the full 5 in a week, running 4 times a week (1.25 each). Once I could do that I chose a day for my “long run” (most people chose a weekend day.) I would add my +10% distance on that day, trying to go further than I did before without stopping.
At first that’s only like .1 or .2 a week. But pretty soon you’re adding a mile and get to the point you can run 1 hour without stopping. I worked my other runs up to how ever far I went in 15 minutes.
Only once I was there did I really start to care about my heart rate. Pretty quickly I was able to run further at lower heart rates. I think at first we are just so weak there is nothing for it but to build up.
@@piedpiper1172 Thank you, that’s helpful to hear. I’ve been able to run for 45-60+ minutes for over 6 months now, but my HR still consistently hits 170+ (over 90% of max) in the first few minutes and then mostly stays at that high level. On rare occasions, it’s slightly lower, for example, on a really good day, I can hold a 167 or so average HR through a 10K distance, but that’s not the norm. Slowing down doesn’t really seem to help because below a certain speed, my form is so poor that it is uneconomical and therefore induces a high HR.
What if anything did you do to reduce your HR once you did start caring about it as you say? Did just more and more running automatically bring it down? That is what doesn’t seem to be happening for me.
@@aroundandround Oh! I’m doing 3-4 miles 3 times a week and 5-6 one time now. Following a half marathon plan. I swap at least one of the shorter runs for low heart rate on the stationary. Most of my runs are in the low 160’s, which is only a little above my zone 2 max, spending about half the time in zone 2.
@@piedpiper1172 Ah cool, that’s about exactly my typical weekly mileage plan these days as well. Except my second mile onwards HR is usually 170+ (90% of my max HR of ~190). I’d be pretty happy if I could jog for even 30 mins at 160 as160 feels so much breezier than 170.
Having read the other comments I will just add. Slow down. Even if it's uneconomical you will get used to that also and you legs.and body will adjust. Just out curiosity are you overweight or what way would you describe yourself?
Also one thing to note is if you are say the 167bpm you mention that doesn't matter really.that much unless compared to your max heart rate or VO2max.
My max heart rate was 199 on a Vow max (it went higher in training ) and my lactic-threshold is just at 141. Yours could be 167 depends on the person.
The guy who did my vow Mac said his and his brothers max heart rates are completely different. So comparing to others would be a bad idea.
Good luck. If you doing that distance you can now Jog so you got there
What is ATP?
Adenosine triphosphate.
idk if I heard your voice before or my brain thinks all British people sound the same
Could you apply this to mountain hiking/climbing, from about 7,000 to 11,000 feet elevation; 3,000 to 5,500 feet elevation gain? Thanks
Lactate does not cause acidosis
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