A question about Lactate Threshold and blood ph

It's not a central part of training, but it's a peripheral part. Lactic acid is technically a misnomer, but I'm sure other people will correct you for that.

Lactate and blood pH are related, but not synonymous. The drop in blood pH during hard running is the result of protons / hydrogen ions / "acid" (H+) being produced when you break down ATP into ADP and phosphate to get energy. This ALWAYS happens when you run fast, no matter whether you are fit or out of shape. The difference is that reforming ATP from spent ADP through the aerobic process (glycolysis plus oxidative phosphorylation) consumes protons, so the net effect is neutral with respect to blood pH. When you rely on anaerobic energy (glycolysis only), there is no mechanism to mop up the extra H+ that is floating around. So even though the conversion of glucose into pyruvate and then into lactate is pH neutral, you haven't addressed the fact that there are protons being dumped into your muscle cells from the breakdown of ATP.

To emphasize, the H+ production from ATP breakdown is non-negotiable - it ALWAYS happens. For the sake of argument, let's set aside running economy for a moment. Let's say we have a 5:00 miler and a 4:00 miler who are the same size and have the same running economy. When they both run 60-sec 400m pace, they both produce the same amount of acid (H+, protons) in their muscles! The main difference is that the 4:00 miler is substantially better at mopping up those protons floating around and using them in the aerobic process to reform ATP. The 5:00 miler does not have the cellular machinery to make that happen, so he relies on glycolysis only to reform ATP fast enough to sustain 60-sec 400m pace. As a result, his blood pH drops much more quickly and he has to stop. This is the MAIN difference between runners of very different fitness levels: the faster runners have a stronger aerobic system. You I'm sure already know how we address this in training: high mileage and high-end aerobic workouts.

Now, with respect to dealing with lactate and blood pH, there are some peripherally important aspects of fitness. Blood pH can be "dealt with" via buffering. Just like you can neutralize vinegar with baking soda, your body uses bicarbonate ions in your blood to buffer against drops in blood pH. This system only works for a little while, though. Lactate itself is also a part of dealing with acidity. If you didn't produce lactate at all, and just let the pyruvate formed during glycolysis float around, you would have your blood pH drop much faster. Forming lactate from pyruvate makes glycolysis pH-neutral, and lactate can "grab onto" a proton from your muscle cell and help transport it out of the cell and into your blood. This helps prevent localized buildup of acidity Lactate itself can also be shuttled around to different places in your body and be burned for energy. We address these aspects of fitness with race-specific interval workouts.

Blood lactate levels and blood pH levels are also not identical - usually they are, but there is a short period where your blood lactate is rising because you're relying heavily on glycolysis to produce energy, but your blood pH has not dropped yet, because your blood buffering system is still churning away, snapping up any stray H+ ions that get dumped into your blood. Soon, the buffering system is overwhelmed and your blood pH drops as your blood lactate rises.

So to answer your question, addressing your ability to "deal with" drops in pH DOES improve your fitness but it is a PERIPHERAL part of fitness. The core problem is how to deal with the inevitable surge of H+ coming from ATP cleavage that is necessary to maintain high speeds, and the answer to this is to improve your aerobic system. Or increase your running economy so you can go faster for the same amount of ATP usage, but that's another story.

This is all addressed in chapter 1 of my book, by the way. It might interest you.

http://www.amazon.com/Modern-Training-Physiology-Long-Distance-Runners/dp/0615790291

That was an awesome explanation! Question for you, due to time constraints I am current only doing tempos and workouts, and taking off on my off days. I thought this would have minimal affect on my training because i have more energy to do the quality days. 3 or 4 per week.

However, when I race I am totally unable to maintain pace. I will run 1 mile at a pace that i do cruise intervals at (moderately easy) then completely die a half mile later.

Is my neglect of purely aerobic develipment the cause of this? Or can I somehow circumvent this problem another way?

running economy is a bit outdated oversimplified at this point

as is any sentence including the term aerobic engine

try to get the big picture first for example it is worthwhile understanding acidity aids the unloading of oxygen in the cell

no acidity, no performance

Northern Star wrote:

. This is the MAIN difference between runners of very different fitness levels: the faster runners have a stronger aerobic system. You I'm sure already know how we address this in training: high mileage and high-end aerobic workouts.

Ahem

Probably, yes that is the cause.

Running more is the simplest and best solution but if you're committed to the 3/4 days a week schedule, you can do the "run less run faster" thing, which basically is this:

Workout 1: short or long intervals

Workout 2: tempo run

Workout 3: long run

Make your long run a workout. Do it kinda fast. That can shore up fitness deficits from suboptimal training.

Well, that's how I do it at least. It works pretty well.

Fantastic response, thank you Northern Star.

Continuation question, would this then mean that any means of causing H+ to increase in the blood would cause aerobic adaptation? Such that whether running, biking, swimming or a (hypothetical) IV drip of hydrogen ions would all have the same effect on the body towards aerobic fitness?

The problem is acid in the muscles, not the blood. The blood downstream in muscle capillaries becomes acidic, the better to make hemoglobin unload O2 and take up CO2, but the acid is quickly diluted by the time it reaches the lungs, and back to normal pH by the time it gets around to the muscle again. The question is how fast can the blood remove the acid from the muscles. If not fast enough, they shut down.

Aerobic adaptation is caused by stressing the aerobic energy system, not by acid clearance. A long workout that stays near the "threshold" of the maximum sustainable rate of acid clearance will not approach the maximum O2 consumption. You use more O2 when well above that threshold, during shorter-duration, unsustainable efforts. As in weightlifting, "lift heavy." Put the maximum stress on the aerobic system for the greatest gains.

Northern Sar, you were doing great with the physiology until you said that tht 5 minute miler and the 4 minute miler produce the same amount of Hydrogen ions. You are making the classic mistake of ignoring the neuroscience, which almost every wannabe guru does on these message boards.

The fact is, the faster runner more biomechanically efficient at faster paces.

I think you are going to have to rewrite that book with a more holistic approach.

You're welcome.

Jon ( pariah of da letsrun fizzyologists) Orange.