The Lactate Threshold ? Reality or Fallacy?
For many years exercise science has perpetuated the concept of a lactate threshold - a point during exercise where a sudden, sharp increase is noted in the concentration of lactate in the blood. This phenomenon is supposedly noticed when blood samples are taken from subjects performing incremental to max exercise tests much the same as a VO2 max test. Traditionally, it has been noted that when concentration of lactate is plotted against running speed (or %VO2 max) on a graph, as the individual runs faster the quantity of lactate in the blood remains constant up to a certain speed, after which a sudden inflection in the gradient occurs. This inflection point has been dubbed the lactate threshold - the point during intense exercise where the muscles become increasingly anaerobic, generating vast quantities of lactate. Therefore, this phenomenon has also become known as the anaerobic or ventilation threshold.
As discussed in an earlier article on lactate featured on this website, early exercise scientists (and even some present day ones) attributed the increasing amounts of lactate in the blood during exercise to a lack of oxygen supplied to the muscles. This theory holds that the cardiorespiratory system must be inefficient at matching blood (oxygen) supply to the muscles and exercise intensity. Therefore, as the intensity of exercise increases, the muscles have to rely increasingly on "oxygen independent" (anaerobic) metabolism and its associated lactate generation. What these researchers failed to understand, or were unaware of was that as the intensity level (power output) of exercise progressively increases, there is a corresponding increase in the dependence of the glycolytic energy system. It is now universally accepted that energy systems are exercise intensity dependent. As explained in the previous article on lactate, this accumulation of lactate is a necessary consequence to maintain the increased flow of energy through the glycolytic pathway.
Tim Noakes at the University of Cape Town, South Africa states that it is highly unlikely that the muscles ever become truly anaerobic. He provides some powerful evidence to back up this statement and quite possibly the most convincing might be what he calls the "lactate paradox". In his studies of the results of several research papers on Everest climbing expedition experiments, Noakes noted that lactate accumulation in the blood actually decreased as attitude increased. This finding is the exact opposite of what one would traditionally expect since as altitude increases, the ambient barometric pressure decreases, as does the relative availability of oxygen in the inspired air. Therefore, one would suspect that near the peak of Everest, the exercising muscles must be truly anaerobic and generating large amounts of lactate but as mentioned previously, this does not occur. Professor Noakes explains that at such an extreme altitude, some internally regulated factor (possibly the brain) severely limits the intensity of exercise to protect the heart therefore also limiting the amount of lactate production. Additional research, has demonstrated that even at rest under more than adequate oxygen availability, muscles generate lactate. Furthermore, other researchers have failed to find conclusive evidence that muscles become anaerobic at exercise intensities approaching the lactate threshold or even during maximal exercise. Therefore, Noakes prefers to refer to anaerobic metabolism as "oxygen independent" metabolism since in his astute opinion there exists no such thing as anaerobic muscle.
Noakes dismisses the probability of a sudden increase in lactate concentration. He explains that if too few blood samples are taken - say for every three or four kilometers per hour increase, then when the rise in lactate is actually observed, it may indeed show a precipitous "jump" from the one observation to the next. If samples are taken more frequently however, say at every speed increment, then the increase is much more gradual, producing a smoother logarithmic or hyperbolic curve. Dr. Noakes indicates that lactate buildup during increasingly intense exercise is the result of its production rate exceeding its clearance. As mentioned in our article,Lactate is NOT the Culprit!, Brook's lactate shuttle is purported as being responsible for assisting with the transport, utilization and clearance of lactate during exercise. At lower exercise intensity levels, the rate of lactate clearance is able to match the rate of production. However, as exercise becomes increasingly more intense and more muscle mass is recruited, proportionately large quantities of lactate are produced, but it is unlikely that clearance via the shuttle will be able to maintain pace. Therefore, there exists a speed or intensity level at which the production of lactate surpasses its clearance and the blood concentration begins to steadily increase. This point is what Noakes prefers to call for lack of a better word ? the "lactate turnpoint" and that it occurs at an intensity/speed where the concentration of lactate in the blood is approximately 3.0 mmol/L. If the individual were to run at this constant speed, this would be called running at the subjects "lactate steady state". In theory this is the fastest speed that can be maintained by the exerciser for extended periods of time such as marathon running.
Therefore, from discussions in this and previous articles, it is safe to conclude that lactate production in the body is the direct result of an increased reliance on the glycolytic energy systems, not from a lack of oxygen in the muscles. Paired with this increased use of oxygen independent metabolism is an increase in lactate production. The sudden jump in lactate production simply does not exist; it increases proportionally with the increased exercise intensity or power output. In addition, it should be obvious that the term anaerobic threshold is a misnomer and that perhaps the only appropriate term to refer to this phenomenon is the lactate turnpoint.
References and further reading: more information on the concept oxygen independent metabolism and the lactate turnpoint may be found in Lore of Running ? a classic book in its fourth edition dedicated not only to running performance, but to cutting edge exercise physiology as well.
David Petersen is a Personal Trainer/Certified Strength and Conditioning Specialist and the owner and founder of B.O.S.S. Fitness Inc. based in Oldsmar, Florida. More articles and information can be found at http://www.bossfitness.com
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Lance Armstrong?s Training Tactics ? The Tortoise or the Hare?
I have been counseling people on weight loss, exercise efficiency and nutrition for over twenty years. Every time I go to the gym I observe people, their training tactics and their workout habits. Over the last few years I have noticed something about certain people in the gym that has been interesting. You would think more people would do this but they don't. What I have noticed is certain people have a habit or process they go through when they workout that most do not. What is interesting is, before I even realize that they do it, I can tell by the way their bodies look that they have this habit. They are leaner, healthier looking, and stronger than most.
Rotator Cuff: Exercises and Strategies to Prevent Injury
Have you ever experienced a dull ache or sharp pain in your shoulder or upper arm? Maybe you are unable to sleep on one side because your shoulder wakes you up at night. Perhaps, you have discomfort reaching behind your back to tuck in your shirt or grab your wallet. If so, you may be suffering from a rotator cuff injury.
Exercise and the Time Clock
I have to admit that I sometimes find it amusing when someone knows I am a trainer and proceeds to elaborate on the hours that they spend in the gym. One example was a few years back when I was introduced to a nice young women, who proceeded to tell me that she went to the gym twice a day, an hour each time. Unless this second hour was spent in the jacuzzi or making up for lost time due to chatting with fellow gym-goers during the earlier timeslot, I would be leary. Instead of being impressed by her exuberant enthusiasm for working out, my thoughts were that one of those hours might be better spent in a counseling office. Excessive exercising is unsafe and a sign of other deep-rooted problems. So, the question remains how many ticks on the clock should pass before you head for the locker room? And what compels a person to go way overboard in their exercise routine?
The Truth About Exercise and Why Its Not Always Good for You!
Exercise is often regarded as a panacea for many things..."if you want to lose weight, you must exercise"; "if you want to get those feel good endoprhins racing, take some exercise"; "if you want to help with stress, you should take up exercise".
Dangerous Shoulder Exercises
Have you ever suffered from shoulder discomfort after working out? I am referring to aching or sharp pain experienced in the front of the shoulder or lateral upper arm that is felt with overhead activities, reaching behind the back or even laying on the shoulder. These symptoms are often indicative of rotator cuff inflammation. This is a common problem for many people who perform resistance training on a regular basis. It is also a problem that can easily be prevented by modifying the following "dangerous shoulder exercises."
Exercise and Heart Health: A Life Giving Marriage
Most people get their health out of a bottle these days, be it a bottle of vitamins or pharmaceuticals. However, with a little effort and dedication you really can get a hold on your life, turn it round and live it to the full!
Tour of Diet ? Cycling for Your Health
The last seven years, or so, at the Tour de France has shown a success story that is very uncommon. Winning seven Tour de France championships is a feat that will be extremely hard to duplicate. Lance Armstrong knew it could be done, even overcoming a life threatening bout with cancer.
The Truth about Spot Reduction
At any point, we can pick up the latest fitness magazine or see a television ad for the newest "abdominal reducer" exercise. These gimmicks are feeding on society's obsession with a "six pack" and everyone is searching for the answer to lose those love handles.
Best Flat Tummy Exercises for Great Female Abs
Are there flat tummy exercises that are the best for great female abs? Abs-olutely! To make this list, the female abs exercises must be safe, effective and can be done nearly anywhere. Your abs can be worked out every day. Here are great flat tummy exercises:
Incorporating Physical Activity into Your Daily Routine Not as Hard as You Think
You already know that getting at least 30 minutes of exercise each and every day is good for you, but putting that assertion into actual practice is an entirely different matter, right? Contrary to what you might think, making physical activity an everyday habit isn't rocket science. There's no secret code for success waiting to be cracked. In fact, it's something that can be worked into your usual routine with minimal, sometimes no, interruption or adjustment.
The Power Workout:
Scenario: I really want to get in shape, but I work all day and attend multimedia classes until 8:30. How do I find the time to exercise, and what are a few good exercises for beginners like me? Solution: Finding time to exercise is certainly a challenge. Even the most motivated among us suffer setbacks during our business's busy season or when a new project is on the horizon. The key to fitting fitness into your busy day is to recognize that finding time isn't the issue--it's making time.
Recognize Your Motivation to Exercise
The positive effects of exercise have been documented and reported through every media outlet available. You can probably walk up to anyone on the street and ask them the positive benefits of exercise and they can most likely list them. If everyone knows why we need to exercise, why aren't we? The answers are most likely more complex than we think.
Professional Triathlon Training Taking You To Your Best
There are hundreds of different programs for professional triathlon training that will work for you. There are even more that won't. For anyone who is looking for some great plans to get them going, think about your needs and your desired outcome.
Top 10 Mistakes To Avoid When Exercising the Abdominals
The abdominal muscles are essential for maintaining good posture and core stability, however many exercisers are unclear on the correct way to exercise them. Traditional exercises for the abdominals include crunches and sit-ups also known as trunk curls and curl-ups. The following are ten things to avoid when performing exercise for the abs.
Top 10 Most Outrageous Exercises I?ve Ever Seen
In the course of my experience working and training in gyms, I've seen people doing some incredibly "interesting" exercises. Unfortunately, it's usually because these people have not been properly instructed in exercise technique.
Exercising for life ? The magic is in the synergy!
Synergy: the working together of two or more things, people,or organizations, especially when the result is greater thanthe sum of their individual effects or capabilities
The Great Forgotten Exercise -- Parallel Bar Dips
When it comes to building lower pectorals, triceps and frontal deltoids, dips are without doubt one the best exercises I've ever used. They are seldom used nowadays and the reasons are plain to see: you have to be able to handle your own bodyweight for reps ? unless you have access to one of those fancy-dan machines that allow you to dip (or chin) with less than body weight.
Life Walking: Dont Walk Just For Exercise - Change Your Life
"Life walking" is more than walking for exercise and fitness objectives. It's the larger ideal of using walking to change your life.
VO2 Max- Exposing the Myth
VO2 max is defined as the maximal amount of oxygen the body is able to extract and use to support work performed by the body. It is therefore an indirect measure of the aerobic power of the body, which is controlled by complex interactions between neural (brain and nervous system), cardiovascular (heart and lungs) and skeletal muscle factors. The equation for VO2 max it is equal to the product of stroke volume (the maximum volume of blood the heart ejects in a contraction) and the arterio-venous difference (the difference between the saturation of the arterial blood and that of the venous blood). The aerobic power of the body will change constantly throughout a well-designed running program due to physiological changes and therefore its usefulness in designing a program and determining running capabilities is questionable. This article aims to explain the reason VO2 max is a better indicator of fitness levels than running potential and conditioning program design.
Exercising - Ways of staying motivated!
The number one reason people say they do not exercise is lack of time. Not long ago, a twenty-year study was completed centering on the theory that, "There is not as much time in the day as there used to be." The study concluded that just the opposite was true. It showed that with all the technology today, we have 1.5 more hours in a day than we did twenty years ago. In other words, with all the gadgets out there to help us communicate and manage our time, we should have an hour and a half more time for ourselves. What is the solution? With a little prioritizing and some time management, we can find the time to exercise!
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