Hi folks, welcome to this video on EPOC, Excess Post-Exercise Oxygen Consumption. Immediately puts people off and makes people panic when you start saying these big words, but what we're talking about here is just the body recovering. So you go into EPOC or you undergo EPOC, however you want to tell me, when you are recovering.
So in between sprints, in between reps, sorry, in between sets, sorry, in the gym, at halftime, at the end of a quarter, at the end of a game, you are in the process of EPOC. And if you actually break down the term, it is something fairly straightforward. Excess, more, post-exercise, after-exercise, oxygen consumption. So following exercise, I am consuming more oxygen.
I'm panting, I'm heavy breathing, I'm fast breathing. That is what EPOC is. Now to be in recovery, we must have got fatigued in the first place.
So let's just have a look at technically what fatigue is. So we are fatigued when we have depleted all of our ATP and PC. Now, if you know about the ATP PC system, that will be after 10 seconds maximum high intensity work.
So all of your ATP and PC has become depleted. I am also fatigued when all of my myoglobin is lost or basically given up its oxygen to the muscle tissue. So myoglobin stores oxygen in the muscle.
When that's all gone, I'm in a state of fatigue. Also, when I've depleted all glucose and glycogen. Now that, you know, those are events that are lasting two hours plus. So that isn't one of the more common ways to fatigue, but it definitely does happen. And I'm also fatigued when I've got high levels of lactic acid accumulated inside of me.
Now, I don't need all four of these to be fatigued. I just need one of these. If I have depleted all my ATP and PC, I'm fatigued in one way. If I've lost all my myoglobin, I'm fatigued in another way. If I've depleted all my glucose and glycogen, I've fatigued in a different way.
And if I've built up lactic acid, I've fatigued in a different way as well. A 100-meter runner, for example, will fatigue because he or she has depleted all their ATP and PC stores. But a 400-meter runner will fatigue because he or she has depleted all of their ATP and PC stores after 10 seconds, but then accumulated high levels of lactic acid because they've used the lactic acid system for the remainder of their event. Whereas a marathon runner will deplete probably due to these two methods. Myoglobin, losing all its oxygen, and glucose and glycogen being depleted.
So different events, different activities have different methods of fatigue. But whenever we fatigue, we've got to recover. And we call this process EPOC.
So EPOC then, how can we sum it up in a simple sentence? It's simply breathing fast and deep, following exercise to increase the amount of oxygen in the body. to return it to pre-exercise state. Now you might see a diagram like this or you might see this exact one in your various textbooks.
Now you know it puts people off but I try and break the diagram down and say right what is each part showing me. So here this is before exercise, there you can see the start of exercise, this is before exercise, this is the amount of oxygen I'm consuming before exercise, not very much, quite labored. Now ignore this red line, this square or rectangle here represents let's say a game of netball but more typically it represents the amount of oxygen needed during that game of netball the amount of oxygen my body requires to complete that game of netball now this red line here what this represents is the area under this red line more specifically represents the amount of oxygen i did consume whilst playing this game of netball So this area in the purple represents the amount of oxygen that my body wanted but I failed to take on board. I suppose you could say the amount of the net bogging that you were playing anaerobically.
So this is how much I did get on board underneath this red curve and that's how much I wanted but failed to take on board. And we call this our oxygen deficit. How much of your effort was anaerobic?
Whereas this area under the red line is aerobic. The volume of oxygen consumed whilst exercising during the event. that's under this area here. So I've just drawn those arrows on there to highlight that fact. This is the oxygen deficit, this is the volume of oxygen consumed whilst exercising and during the event, in this case a game of netball.
So what we've got now is we've got this bit after the graph, sorry after our game of netball has finished, and this whole area here is EPOC. Now this is the amount of oxygen we've got to consume after exercise. to get our levels back down to normal. In other words we've got to repay the deficit.
that we built up during our game of netball. So this is epoch and what I could even do here is, if I draw a line somewhere across there like that, what we've got above this line is what we call the fast component of epoch and if you've got a fast component we also must have a slow component. I'm going to deal with that in a second. Now the fast component of epoch, what does that mean? It means what happens in the first two to three minutes of us finishing our event.
So our event, our game of netball is finished and we are straight into EPOC and technically we are straight into the fast component of EPOC. Now I'm actually going to come to these bits here. The fast component of EPOC is what happens in the first two to three minutes of finishing our event. And it takes one to four litres of oxygen or additional oxygen to do this. So what do I do with one to four litres of additional oxygen in two to three minutes?
following my event? Well, I am resynthesizing all of ATP and PC and I'm replenishing all my globin. If you think back to a few minutes ago, there were two causes of fatigue, weren't they? The depletion of ATP and PC and the fact that my globin has given of all of its stores of oxygen up.
So we can recover, we can get rid of two of those causes of fatigue within three minutes of finishing exercise using one to four liters of oxygen. And if you want to really impress the examiner, you can really impress people. Even though it takes... three minutes to resynthesize all ATP and PC. We actually resynthesize 50% of our PC in just 30 seconds.
But then it takes us another two, two and a half minutes to get the other 50% resynthesized. But all that is achieved in the fast component of EPOC. All that is done within two to three minutes of finishing exercise when you're doing your fast deep breathing.
And like I said, if we've got a fast component of EPOC, this one here, we must also have slow component of EPOC which is this one here. Now the slow component of EPOC as you'd expect takes a little bit longer to achieve its goals but what are the goals of the slow component of EPOC? Well what we are trying to do is we are trying to remove all lactic acid out of the body and we're also trying to maintain ventilation and body temperature. and that requires all those processes require an additional five to eight liters of oxygen and can take minutes up to a couple of hours a few hours depending on how hard you worked how much lactic acid you accumulated during your game during your event now many students my students hate epoch you know it's really difficult but that is genuinely it i think sometimes people overthink it and try to overanalyze it remind yourself what is epoch you are fast deep breathing After your event, we all do it, it's the pushing in for our recovery.
And within two to three minutes of finishing our event, we've taken on board one to four litres of additional oxygen. And that has been used to resynthesise all of our ATP and PC stores and replenish all of our myoglobin. Right. We're still breathing slightly elevated for a few minutes, up to a couple of hours after activity.
And that's because we're taking on board an additional five to eight litres of oxygen to remove any lactic acid that we built up and to maintain ventilation. and to maintain circulation and body temperature. Now for those that want a bit of additional detail this little component one is where we can add it. So you know we've got lactic acid, when we react to lactic acid with oxygen after our event when we're taking on board this extra oxygen we can convert lactic acid back into pyruvic acid.
So if you know your aerobic energy system you'll know that. That pyruvic will then convert to a C-talcoenzyme A. It re-enters the Krebs cycle. And you don't, as far as I'm aware, need to know these percentages. But you do need to know what lactic acid gets converted into. So lactic acid gets converted into cand dioxide and water, glycogen, glucose, and protein.
So actually, lactic acid is quite a useful substance to have inside of me after an activity. I can convert it into five things. One of them I don't want, CO2, but I can breathe that out. These five, water, glycogen, glucose, and protein.
They're going to speed up my recovery process. So that's what my body does with lactic acid during the slow component of EPOC. And secondly, what we're doing in the slow component of EPOC is we are maintaining ventilation circulation.
Now, what do we mean by that? Well, we need to let our breathing rate gradually lower back down to its normal level because I want to keep oxygen delivery high. But equally, I want to remove CO2.
You've produced quite a lot of CO2 that's still going to be in your system. It's still going to be in the bloodstream. and we need to maintain breathing rate and ventilation and circulation in order to get that CO2 out.
Also, heat production is higher than heat removal during exercise. So our temperature needs to remain elevated after exercise to allow for a more gradual decrease in body temperature. Our body doesn't like sudden sharp shocks.
So you've been running around producing and generating loads of heat and then suddenly you stop and you're not generating as much heat. We don't want your temperature to suddenly plummet. We need to be more gradual.
So Elevated breathing rate allows us just to maintain that a gradual drop in body temperature. So finally then, how can we use this knowledge of EPOC? How can we use this knowledge to allow our athletes to recover quicker? Because essentially that's what we want them to do. We want them to recover quicker.
Now, weirdly, a warm-up can speed up your recovery after exercise. And the reason that is, if I warm up, I'm going to increase my oxygen delivery in my blood and in my muscles before my game starts. We keep saying it's the game of netball.
If I can increase the amount of oxygen in my system before the game of netball, that's going to minimize the oxygen deficit. I'm not going to have as big a deficit because I had more oxygen in my system to start with. So that's one way.
Number two, active recoveries or cool downs. So this is the importance of going on a cool down. It allows you to get more oxygen into the system after your event.
So it allows you to resynthesize all the ATP and PC quicker, replenish your myoglobin, and also remove the lactic acid quicker, as well as maintaining. your ventilation, your circulation and your gradual drop in body temperature. We also need to make sure we train people specifically because if we train you to recover quicker, your body will adapt and learn to recover quicker as well.
We need to train and reflect the demands of the activities as well. Using certain strategies such as timeouts, I've played sports before with timeouts where the coach has deliberately called a timeout just to give us 30 seconds to catch our breath. It doesn't have to be anything other than that. So good use of rotating players, you know, in and off the bench, interchanges, things like that.
And also timeouts allow us to recover more effectively as well. And also diet and nutrition. If we can eat the right things, enough carbohydrates, enough glucose, glycogen, protein, it will minimize the amount of time we need to recover. So these are strategies that a coach can use in order to speed up our recovery.
And that is everything that you need to know on the recovery process. also known as EPOC. Hope you found this video useful folks.