Tips for Stress free life > Expert Zone > Exercise
Exercise Tips by experts
|
| |
|
| |
|
|
Tips for Stress free life > Expert Zone > Exercise Exercise Tips by experts |
|
|
|
|
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 NOTE: You're free to republish this article on your website, in your newsletter, in your e-book or in other publications provided the article is reproduced in its entirety, including this note, author information and all LIVE website links as above.
MORE RESOURCES: See the complete list of Articles on Exercise here Have a look at Best Selling Books on Exercise
See also : Other articles on
Depression,
Grief Loss,
Happiness,
Humor,
Inspirational,
Motivation,
Exercise - Google News
Why not be an expert yourself ? If you can write on
any of the above topic, you are welcome to submit your Submit
your article here |
 |
|
|
RELATED ARTICLES
Optimize Your Exercise: Maximizing the Time Spent Working Out Diet and Exercise are the inseparable twins that are seen and heard everywhere weight loss and fat loss are mentioned. This article will focus on techniques and tips that will help you to maximize the time you spend exercising. Exercise Tips Exercise TipsThe most effective exercise regimen includes both strength training and cardiovascular (aerobic) training in a consistent, regular program.· 2-4 days of strength training and· 2-5 days of aerobic activity; or· 3-4 days of circuit training. Top 10 Exercise Mistakes and How To Fix Them This is a list of ten common mistakes made during exercise. Quite often the exerciser and even the personal trainer or coach is unaware of these mistakes, decreasing the effectiveness of the exercise and even risking injury. No Pain, No Gain Isnt True For Arthritis, But Exercise Is Still Important Recent studies have shown that exercise may acually help people with arthritis in a number of ways. It can reduce joint pain and stiffness. Exercise Is a Key to Good Health for All of Us There's plenty of evidence that an essential component of a healthy life is physical activity. It has been shown that exercise has a positive effect on both your body and mind. After WLS: Walking for Wellness Step for step, mile for mile, walking is the best cardiovascular activity you can include as part of your weight loss surgery success story. Walking is easy, accessible, inexpensive, individual and effective. How to Pick a Good Personal Trainer One of the major benefits of the YourBestBodyNOWProgram and several other programs like it is that you can lose weight and meet your fitness and weight loss goalseven if you have neither the time nor money to get a personal trainer.At the same time, if you do ultimately decide to hire trainer at some point,I want to make sure that you are going about it in a way that will bring you the absolutemaximum benefit. Get Moving...The Benefits Will Last a Lifetime! The benefits of physical activity are numerous and very well documented. Aside from substantially reducing the risk of dying of a heart attack, regular physical activity decreases the risk for stroke, diabetes, high blood pressure and certain forms of cancer. 2-Minute Fitness Why would I want to write about yet another fitness program? There are so many out there. There is no escape from fitness programs whether you watch TV or read a magazine or newspaper. Top 10 Tips For Finding Time For Exercise If you're like most people, finding time for exercise is difficult. Here are my "top 10" tips to help you in that quest. Strength Training FAQs Do you need some beginner's strength training 'how to' information? I know you must have tons of questions. I will try my best to cover most of the beginner questions with this article. The Importance of The Fibonacci Numbers in Fitness Training "Things do not change; we change." -Henry David ThoreauThe following article is a chapter from my new book, The Da Vinci Fitness Code. Core-Principles: The Function of Functional Training Okay?okay?okay! Enough already!!! It seems like with every new term, every new invention or just about anything that is seemingly not "Everyday" that we all become flustered and assume we know nothing, which is both a testament to our lack of faith in ourselves and also a reflection of our ever-growing dependence on externals to give us a little reassurance where our natural instincts should be in high gear.My intention with this article is not to offend anyone especially those that whom, without their continual support I would surely be seeking a new line of work, and yes I am referring to my clients, so please don't feel like I'm bashing "you" if I ever refer to any particular individuals or events, no names will be mentioned though. Pilates: A Challenging and Motivating Exercise Regimen Pilates is named after its creator Joseph Pilates. It is an exercise regimen that uses machines and special stretches. Exercise Intensity "Physical Fitness"Some physical activities (exercise) are not intense enough to help you meet the FDA recommendations for being physically fit. Although you are moving, these activities do not increase your heart rate, so you should not count these towards the 30 or more minutes a day that you should strive for. Wise Up and Invest in Your Workout Success - Six Top Fitness Faux Pas Already dedicated exercisers make small but costly mistakes regularly in their workouts, and one tiny change can have a huge impact on their results. Time is valuable, and for each precious moment invested you want to ensure the best possible return. Sports Specific Exercise The Greek physician Galen (AD 129 - 210) is generally accepted to be the originator of formalized exercise, he even pointed the way forward by stating,"?movements which do not alter respiration are not called exercise".Whilst he was chief physician to the Gladiators, Galen devised training drills to replicate movements from the arena, as seen in the 1960 film Spartacus. Weight Loss, Bodybuilding, and Exercise Tips - Keeping Your Body-fat Low: Part 2 of 10 My name is Greg Ryan. I am a fitness expert, professional bodybuilder, personal, trainer to movie stars, former employee of Kathy Smith and over 50, 000 hours of paid personal training sessions under my belt. Who Else Wants To Get In Shape in 35 Minutes? Most of the physical fitness trainers, and coaches agree thatdoing some sort of resistance training, and cardio training, setsup a good foundation for all around fitness. What most peoplelike to do is alternate days. 3 Exercises for Good Posture and a Six-Pack These days many people spend a significant part of their day slaving away over a hot computer and as a result, their posture is not what it should be. Bad posture can result in short-term discomfort such as neck stiffness and headaches and also lead to more serious problems in later life.
|
|
You are here |
|
| Exercise Home | Exercise Tips - Complete list | |
|
| Main Home | | Meditation Corner | |
|
|
| Recommend us | |
|
[About
us] [Contact] [Privacy
Policy]
Copyright 2006, Meditation
is Easy.com, All
rights reserved
