Too much lactic threshold work destroys mitochrondria?

Happy Education to all wrote:

Let's get this straight, for once...

The formation of lactate FROM pyruvate is catalyzed by the enzyme LACTATE DEHYDROGENASE. Sometimes, MISTAKENLY, the end result of this reaction is said to be the formation of LACTIC ACID. However, due to the physiological pH and earlier steps in gycolysis that consume protons, lactate, rather than lactic acid, is the product of the lactate dehydrogenase reaction. Although the muscular fatigue experienced during exercise often correlates with high tissue concentrations of lactate, lactate is not the cause of fatigue.

Hydrogen Ion (H+) accumulation during fatigue reduces intracellular pH, inhibits glycolytic reactions, and directly interferes with muscle's excitation-contraction coupling, possibly inhibiting calcium binding to troponin, or by interfering with crossbridge recycling.

However, evidence suggests that other mechanisms, such as the simple hydrolysis of ATP, are responsible for most of the H+ accumulation and that lactate itself actually works to decrease metabolic acidosis rather than accelerate it.

In fact, lactate is often used as an energy substrate, especially in Type I and cardiac muscle fibers.

Lactate production increases with exercise intensity and appears to depend on muscle fiber type.

(Essentials of Strength Training and Conditioning, Chapter 3 - Bioenergetics of Exercise and Training, pg 48)

The Bohr effect enables the body to adapt to changing conditions and makes it possible to supply extra oxygen to tissues that need it the most. For example, when muscles are undergoing strenuous activity, they require large amounts of oxygen to conduct cellular respiration, which generates CO2 (and therefore HCO3− and H+) as byproducts. These waste products lower the pH of the blood, which increases oxygen delivery to the active muscles. Carbon dioxide is not the only molecule that can trigger the Bohr effect. If muscle cells aren't receiving enough oxygen for cellular respiration, they resort to lactic acid fermentation, which releases lactic acid as a byproduct. This increases the acidity of the blood far more than CO2 alone, which reflects the cells' even greater need for oxygen. In fact, under anaerobic conditions, muscles generate lactic acid so quickly that pH of the blood passing through the muscles will drop to around 7.2, which causes haemoglobin to begin releasing roughly 10% more oxygen.

Bohr effect wrote:

Bad Wigins was referring I believe to what is discussed in the second paragraph of the section 'Physiological role' at the following link.

https://en.wikipedia.org/wiki/Bohr_effect

I quote:

The Bohr effect enables the body to adapt to changing conditions and makes it possible to supply extra oxygen to tissues that need it the most. For example, when muscles are undergoing strenuous activity, they require large amounts of oxygen to conduct cellular respiration, which generates CO2 (and therefore HCO3− and H+) as byproducts. These waste products lower the pH of the blood, which increases oxygen delivery to the active muscles. Carbon dioxide is not the only molecule that can trigger the Bohr effect. If muscle cells aren't receiving enough oxygen for cellular respiration, they resort to lactic acid fermentation, which releases lactic acid as a byproduct. This increases the acidity of the blood far more than CO2 alone, which reflects the cells' even greater need for oxygen. In fact, under anaerobic conditions, muscles generate lactic acid so quickly that pH of the blood passing through the muscles will drop to around 7.2, which causes haemoglobin to begin releasing roughly 10% more oxygen.

I for one did not know anything about this, so am grateful for him bringing it up! I think that what he was saying is simply that drops in acidity in the blood flowing through muscles is a fundamental and natural part of the physiology of hard workouts, and thus should not be a cause for concern.

I am not 100% sure about the exact details of what happens when there is 'too much lactate' yet; is it that the acidity of the blood outside the muscles drops a bit as well, so that this 'Bohr effect' no longer works properly, and hence the muscles can no longer perform?

I am Sam wrote:

Happy Education to all wrote:

Let's get this straight, for once...

The formation of lactate FROM pyruvate is catalyzed by the enzyme LACTATE DEHYDROGENASE. Sometimes, MISTAKENLY, the end result of this reaction is said to be the formation of LACTIC ACID. However, due to the physiological pH and earlier steps in gycolysis that consume protons, lactate, rather than lactic acid, is the product of the lactate dehydrogenase reaction. Although the muscular fatigue experienced during exercise often correlates with high tissue concentrations of lactate, lactate is not the cause of fatigue.

Hydrogen Ion (H+) accumulation during fatigue reduces intracellular pH, inhibits glycolytic reactions, and directly interferes with muscle's excitation-contraction coupling, possibly inhibiting calcium binding to troponin, or by interfering with crossbridge recycling.

However, evidence suggests that other mechanisms, such as the simple hydrolysis of ATP, are responsible for most of the H+ accumulation and that lactate itself actually works to decrease metabolic acidosis rather than accelerate it.

In fact, lactate is often used as an energy substrate, especially in Type I and cardiac muscle fibers.

Lactate production increases with exercise intensity and appears to depend on muscle fiber type.

(Essentials of Strength Training and Conditioning, Chapter 3 - Bioenergetics of Exercise and Training, pg 48)

Thank you for your service....not that it will stop the theories of the ignoramuses though

theory wrote:

LateRunnerPhil wrote:

Magness figured this out long ago -

Slow-twitch athletes (60%+ ST fibers in legs) can run RIGHT at the threshold for a long time/lots of volume, and press it down.

If you do that with a fast-twitch athlete (45% or less ST), it WILL impair his anaerobic abilities a lot. This is bad, as this is what the fast-twitch runners thrive off. Also, they would struggle to maintain the intensity of a threshold run, so they either need to break it up in something like mile repeats with short rest or faster aerobic intervals.

Would you be able to summarise the reasoning behind this, or link to a place where Magness gives such reasoning?

Nothing wrong at all with splitting up tempo runs into longish intervals no matter what the type of runner, but I don't immediately see why longer tempo runs could be harmful for a fast twitch runner. More demanding than for a slow twitch runner: perhaps, yes. But actively harmful if followed by appropriate rest?

Fogrunr wrote:

not a scientist wrote:

Running too hard too often destroys the aerobic base that you've spent all that time building.

I can't remember where I heard this. Maybe babbled by Sage Canaday?

Is this correct?

The big component is mitochondrial enzymes. During prolonged weeks of aerobic base building, the density of the mitochondrial enzymes increases amazingly. Just like anything there is a sweet spot for optimum enzyme density development. I find the sweet spot and keep it there during all my runs. If I have to walk the hills, I walk them. As the weeks passed by during a 4 to 5 month base building period, my training pace gets faster and faster while holding the same heart rate. It takes self-control to resist the urge to crack up my heart rate. But after trying the other way for many years, I invested myself fully. During three winter base building. I had results that astounded me.

But you have to push the edge. Keep it just below where you're going over beyond the upper limit of aerobic.

Think of it as rolling a ball uphill in one of those little games with the 2 steel rods. You need to study patience.

also I want to know that when I do my base building I make sure I do it entirely on soft surfaces: grass or dirt. The logic is that you maintain optimum flexibility in your tendons and muscles.

That's spring equals free energy and speed.

For a reference my max heart rate is 216.

In the beginning of base building I'll keep my heart rate below 140 for the first 3 weeks. Then I'll let it go up to 148 for one month. And then 155. For me 155 is my sweet spot. And in the third or fourth month I'm doing everything between 148 and 162. The differences in the beginning I was doing 8:30 pace on trails. And in the 4-month I'm doing 6:30 pace at the same heart rate. The reward for the patience is worth it.

After four or five months of that, when I began racing, I feel like I have a V12 engine in my lungs. I'm running fast and my heart rate is up and the overwhelming feeling is that I want to run faster.

Notice that I didn't do this aerobic base building on flat ground. I build my strength by running hilly trails.

Best of luck to you.

Fogrunr wrote:

Doc strange but loving wrote:

Pretty similar max to me. I was at 213 (on the bike) and could average about 195-198 (if fresh) for about 15 minutes. If your max is 210+ I’d assume you could hold 190+ for 15-30 minutes, but it doesn’t sound like that’s the case?

Oh! Holding that heart rate for that long it's really impressive!

No, I don't think I can do that.

Or at least I don't want to!

The resulting stomach convulsions are pretty unpleasant.

My high school mile was just 4:44, freshman college was 4:36.

So 16:04 5K at 35 I think was pretty good. Also 16:41 at 48, and 16:38 at 52. I did some track and road miles in the 4:52 to 4:41 range in my late 40s to early 50s.

I've done a lot of 20 mile runs, and several runs 30 - 32 miles. 50 miles twice. How does 50 miles feel? It hurts!! Lol.

Interesting thing about doing 50 miles: after the race, it took my heart rate about 3 to 4 weeks to drop from 60 beats down to my normal of 40. And I was only averaging 9:30 to 10:30 miles. so my heart rate was elevated 20 beats for 3 to 4 weeks after doing 50 miles. I have a lot of friends who do ultras... Up to 100 miles.