Speaking of Lactate….

Here’s the bottom line from Professor Brooks: “The world’s best athletes stay competitive by interval training. The intense exercise generates big lactate loads, and the body adapts by building up mitochondria to clear lactic acid quickly. If you use it up (as an energy source), it doesn’t accumulate.”

The job of the athlete is to train in a way that causes the mitochondria to process lactic acid faster and more efficiently.

Lactic acid is a fuel. To improve your capacity to use it as a fuel, you must increase the lactic acid load very high during training. (For more details, see my earlier article:http://www.cbass.com/Lacticacid.htm )

Dr. McGuff is on top of this new thinking. He says that high-intensity intervals and high-intensity strength training both perform the same function: they improve aerobic function by forcing the mitochondria to burn lactic acid more efficiently.

“It is during ‘recovery’ from high intensity exercise that you’re actually getting an increased stimulation of the aerobic system equal to or greater than what you would get from conventional steady-state ‘aerobic’ exercise,” McGuff writes.

“If you have been subjected to proper physical training, you can actually make good use of the lactic acid that is produced. If you are intent on improving your aerobic capacity, it’s important to understand that your aerobic system performs at its highest level when recovering from lactic acidosis,” McGuff adds. “It is also important to understand that since muscle is the basic mechanical system being served by the aerobic system, as muscle strength improves, the necessary support systems (which include the aerobic system) must follow suit.”

To improve the ability of your aerobic system to use lactic acid as a fuel, McGuff says: Lift weights. And then, let your mitochondria take over from there. Get your aerobic benefit on the “drive home from the gym or off to lunch or back to work.”

For McGuff, productive exercise begins and ends with strength training. THE key stimulus for strength—and aerobic fitness—is high-intensity muscular effort.

To see and hear Dr. McGuff explain, in 5:50 minutes, just about everything we’ve talked about so far—and why he believes ‘cardio’ really doesn’t exist—visit You Tube: http://www.youtube.com/watch?v=RiHhc7eLpQY  

More Lactate:   

Before we talk about determining blood lactate levels, we need a deeper understanding of the energy producing systems at play, as well as some commonly used terminology.

There are 2 main systems for producing energy in the body, the aerobic system and anaerobic system. There is a 3rd system, the Creatine Phosphate system, which provides energy for very short bursts of a few seconds, or until your creatine phosphate stores are depleted. we will concentrate on the 2 main ones.

The aerobic system or aerobic metabolism, utilizes oxygen, using predominately fats & some carbohydrates for energy along with recycled lactate which is produced at low levels and metabolized efficiently. This is your endurance energy system. You may still have recurring nightmares about this from freshman biology, also known as the Krebs (or Citric Acid) Cycle

Your lactate threshold (LT) is a highly aerobic point where lactate levels in the blood are still low but just starting to reach steady state levels. Your LT is the most efficient effort level that you can sustain for long periods of time without going in to your energy reserves (i.e. glycogen). Beyond this point, you are exceeding your ability to recycle lactic acid back into the Citric Acid Cycle and lactate levels begin to rise; changing local blood pH and affecting local chemical reactions. 

The anaerobic system does not utilize oxygen, using predominantly carbohydrates for energy. An efficient anaerobic system will produce a lot of lactic acid as its by-product. As you know, in large amounts, this causes the burn and fatigue you often feel when working hard.  Thus, your anaerobic threshold (AT) is much more stressful and is therefore only sustainable for shorter periods of time.

What does this mean?

For the endurance athlete, the BALANCE of these two systems must be developed optimally for their chosen event. Performing a lactate test (to be discussed in another post) will help determine the relative contribution of each system. In general, the well-developed endurance athlete will produce very little lactate even at high speeds. Endurance sport athletes, such as cyclists, Ironman athletes, triathletes and top marathon runners need to be highly aerobic, which means that very little lactate is produced even at peak speeds and testing reveals a very flat lactate curve. Most of their energy comes from aerobic sources.

Optimizing lactate threshold development is the main goal of endurance training, and racing at or near LT proves the most efficient route to a solid race day performance.

So, how can you use this information for training? Watch for an upcoming post on Lactate testing.

Yup, we know a thing or two about gait AND training. 

The Gait Guys: Ivo and Shawn

Green bodies: Lactic acid as a fuel source?

Your body can be greener? We don’t mean being a leprechaun. We mean being a better recycler. Read on…

For years, we’ve been told that lactic acid is a waste product that burns and shuts down muscles. It’s something athletes and fitness exercisers are urged to avoid. You’re told to work out just below your lactate threshold, where lactic acid begins to accumulate.

Well, some of that is correct, but it seems, most of it is wrong. 

The aerobic and anaerobic energy systems have long been thought to operate as separate and distinct systems. Lactic acid was considered the enemy of aerobic metabolism, with the power in sufficient accumulations to bring it to a halt. But we are smarter than that now…

 UC Berkley integrative biology professor George A. Brooks,  has been studying lactic acid since doing his doctoral dissertation on the subject in the ‘70s. Brooks says the idea that lactic acid is bad and to be avoided “was one of the classic mistakes in the history of science.”

“The understanding now is that muscle cells convert glucose to lactic acid,” Brooks explains. “The lactic acid is taken up and used as a fuel by mitochondria, the energy factories in muscle cells. Mitochondria even have a special transporter protein to move the substance into them.”

So, your ability to recycle lactic acid into the Krebs (or Citric Acid Cycle) reflects a great deal about your aerobic performance and capacity. Aerobic metabolism and anaerobic metabolism, in fact, operate side by side in the mitochondria. The heart, slow-twitch muscle fibers, and breathing muscles actually prefer lactate as a fuel during exercise. In short, lactic acid is a significant energy source, actually a good thing.

Hinting, or perhaps suggesting, how athletes can and are using this revelation, Professor Brooks said in a recent press release: “The world’s best athletes stay competitive by interval training. The intense exercise generates big lactate loads, and the body adapts by building up mitochondria to clear lactic acid quickly. If you use it up [as an energy source], it doesn’t accumulate.”

Too much lactic acid is still bad, however. It causes distress and fatigue during exercise, altering the local pH of the tissues and changing chemical reactions.  In extreme circumstances it can damage muscle cells.

So how can you learn to use lactic acid to your advantage? Stay tuned for the next lactate installment, coming to a Gait Guys Tumblr Blog near you….

Ivo and Shawn