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SCIENCE CORNER

Lactic Acid and Running – It’s Not Debatable Anymore

There are a lot of subjects in the world of running that are controversial enough to support a debate or criticism. Strength training for runners, classic periodization versus multi pace training, high volume versus high quality and dynamic versus static stretching are just some examples of running themes that have both pros and cons. When writing or speaking about subjects like those I expect and welcome both disagreements and debates. It can be both enjoyable and educational to both sides of the debate. But there is one subject that I feel is incontrovertible. That subject is lactic acid.
The myth that lactic acid is a waste product that causes muscle fatigue just continues to hang on despite the volumes of recent scientific literature that proves just the opposite. All current research shows that lactic acid is not only a valuable source of energy but may actually help prevent muscle fatigue.
The long held association between lactic acid and running began way back in the 19th century when chemists found that juice fermented without adequate oxygen developed acid products. About 50 years later, the scientists of the time found that muscles worked to exhaustion also accumulated lactic acid. Those early researchers then prematurely assumed that the lactic acid was the cause of the muscle fatigue. That remained the accepted theory for many years and still hangs on today. But those early scholars made the mistake of putting the cart before the horse. They just assumed that the lactic acid was causing the fatigue. They didn’t consider that perhaps the lactic acid was the bodies response to muscle fatigue rather that the other way around.
Our bodies are incredibly efficient. There is no process in place that isn’t needed. Even pain has a purpose. It’s a signal to us that something is going on that your body doesn’t like. There is also a purpose to lactic acid. It isn’t just a waste product that throws a wrench into our body works.
As our knowledge of the role of lactic acid grew it became evident that those early beliefs may be wrong. In the mid 1980’s, researchers discovered the “lactate shuttle”, which showed that lactic acid moves freely in and out of muscle cells to provide quick energy and also to produce glycogen. The lactate shuttle works like this - the lactate that leaves a muscle cell may be picked up by a nearby muscle cell or travel through the blood stream to other muscles cells or tissues. The cells picking up the lactate can either convert the lactate back to pyruvic acid, which then enters the Krebs cycle to produce energy or can be converted into glucose or glycogen which enters glycolysis to produce energy.
That news that lactate provides large amounts of energy should have been enough to convince runners that lactic acid is a good thing, but the myth stuck around. Runners, coaches and even expert running commentators still called lactic acid a waste product. Nearly every distance running event on television had a commentator talking about lactic acid causing “oxygen debt.” Now we have even more research that proves the value of lactic acid. Two recent studies, one in Denmark and the other in Australia have proven that lactic acid actually fights fatigue and makes your muscles contract more efficiently.
Your muscles only contract when your central nervous system (CNS) tells them to. Your CNS does this by sending an electrical signal to your muscle cells. Your muscles contract when the electrical charge causes potassium inside your muscle cells exchange places with sodium outside your muscle cells. During intense exercise, potassium ions have a hard time finding their way back inside the cells and they start to build up outside your muscle cells. This build up reduces both the electrical charge and the ability of your muscles to contract. In other words you begin to suffer from muscle fatigue.
This is where lactic acid comes to the rescue. Both studies showed that accumulating lactic acid is used to diminish the effects of the accumulating potassium ions, help them back inside your muscle cells and restore the function of the CNS signaling system.
New research is on the fatigue reducing role of lactic acid is flowing in like a raging river. As new discoveries are made the role of lactic acid will continue to grow and change. What is clear is that our bodies are smarter than we are. Every function plays an important role whether we know it or not. What is also clear is that the idea that lactic acid is a waste product is dead and gone. Isn’t it time to put it to bed?


Start running and watch your brain grow, say scientists

The health benefits of a regular run have long been known, but scientists have never understood the curious ability of exercise to boost brain power.
Now researchers think they have the answer. Neuroscientists at Cambridge University have shown that running stimulates the brain to grow fresh grey matter and it has a big impact on mental ability.
A few days of running led to the growth of hundreds of thousands of new brain cells that improved the ability to recall memories without confusing them, a skill that is crucial for learning and other cognitive tasks, researchers said.
The new brain cells appeared in a region that is linked to the formation and recollection of memories. The work reveals why jogging and other aerobic exercise can improve memory and learning, and potentially slow down the deterioration of mental ability that happens with old age.
"We know exercise can be good for healthy brain function, but this work provides us with a mechanism for the effect," said Timothy Bussey, a behavioral neuroscientist at Cambridge and a senior author on the study. The research builds on a growing body of work that suggests exercise plays a vital role in keeping the brain healthy by encouraging the growth of fresh brain cells.
Previous studies have shown that "neurogenesis" is limited in people with depression, but that their symptoms can improve if they exercise regularly. Some antidepressant drugs work by encouraging the growth of new brain cells.
Scientists are unsure why exercise triggers the growth of grey matter, but it may be linked to increased blood flow or higher levels of hormones that are released while exercising. Exercise might also reduce stress, which inhibits new brain cells through a hormone called cortisol.
The Cambridge researchers joined forces with colleagues at the US National Institute on Ageing in Maryland to investigate the effect of running.
They studied two groups of mice, one of which had unlimited access to a running wheel throughout. The other mice formed a control group. In a brief training session, the mice were put in front of a computer screen that displayed two identical squares side by side. If they nudged the one on the left with their nose they received a sugar pellet reward. If they nudged the one on the right, they got nothing.
After training the mice went on to do the memory test. The more they nudged the correct square, the better they scored. At the start of the test, the squares were 30cm apart, but got closer and closer together until they were almost touching. This part of the experiment was designed to test how good the mice were at separating two very similar memories. The human equivalent could be remembering what a person had for dinner yesterday and the day before, or where they parked on different trips to the supermarket.
The running mice clocked up an average of 15 miles (24km) a day. Their scores in the memory test were nearly twice as high as those of the control group. The greatest improvement was seen in the later stages of the experiment, when the two squares were so close they nearly touched, according to a report in the Proceedings of the National Academy of Sciences.
"At this stage of the experiment, the two memories the mice are forming of the squares are very similar. It is when they have to distinguish between the two that these new brain cells really make a difference," Bussey said.
The sedentary mice got steadily worse at the test because their memories became too similar to separate.
The scientists also tried to wrong foot the mice by switching the square that produced a food reward. The running mice were quicker to catch on when scientists changed them around.
Brain tissue taken from the rodents showed that the running mice had grown fresh grey matter during the experiment. Tissue samples from the dentate gyrus part of the brain revealed on average 6,000 new brain cells in every cubic millimeter. The dentate gyrus is part of the hippocampus, one of the few regions of the adult brain that can grow fresh brain cells.


The Many Benefits of Running

There are a number of different benefits which an individual can gain from running on a regular basis. There are some runners who run simply for the joy of running but there are others who run because they realize there are a great deal of benefits which can be gained from rigorous exercise such as running. Some of these benefits may include weight loss , improved cardiovascular health, improved bone health, improved mood and better coordination. This article will briefly describe how running can result in each of these benefits.

Those who are looking to lose a few pounds often find running to be one of the most effective forms of exercise for helping them to achieve their ideal body weight. Running is an excellent form of exercise for losing weight because it requires a great deal of energy. This energy requirement means the body burns a large number of calories while running. The number of calories burned while running is typically significantly more than would be burned during less taxing forms of exercise such as walking or doing yoga. The simplest formula for weight loss includes burning off more calories than the individual consumes. When this type of calorie deficit is created, the body begins to shed excess weight in the form of fat. In order to lose one pound of body weight, the body must create a calorie deficit of 3500 calories. This is equal to burning 500 calories per day. Most runners can easily burn off this many calories in less than one hour of exercise. The number of calories burned while running depends on a number of factors including the individual’s weight, the intensity of the workout and the efficiency of the runner. 

Improved cardiovascular health is another benefit of running. Some of the benefits of running include lowering the blood pressure and helping the arteries to maintain their elasticity. While runner, the arteries expand and contract approximately three times as much as they do when you are sedentary. This means you are not only working out to improve your physical appearance but also the overall function of your body. In doing this the risk of heart attack and stroke becomes diminished.

Running is also beneficial for slowing down the aging process. Those who run regularly are less likely to experience bone and muscle loss as they age at the same pace as those who do not run regularly or at all. The bones grow and become stronger by responding to physical demands. Those who lead a rather sedentary lifestyle do not put this type of demand on their bones and as a result the bones may become weaker. When this happens the individual is more likely to be susceptible to osteoporosis as they age. Conversely, those who run on a regular basis are continually taxing their muscles and their bones so the bones are stimulated to remain stronger and do not as easily weaken with age.

Running can also have many psychological benefits. Most significantly runners typically report being happier and feeling less stressed than their counterparts who do not run or exercise regularly. Running actually has the ability to alter an individuals moods because hormones called endorphins are released while running. These hormones create a sense of euphoria often referred to as a runner’s high and can result in an improvement in the runner’s mood. Running has also been reported to alleviate stress in most runners. There are a number of factors which may contribute to running lowering stress levels. One of the most obvious reasons is the act of running allows the individual to focus on the task at hand instead of being worried or stressed about work, family or other stressors in his daily life. Additionally, running can be very challenging on the body which can result in the individual feeling a sense of accomplishment by completing the run which shifts the focus of his attention from negative stressors to a sense of pride and accomplishment

Improved coordination is another worthwhile benefit which may be gained from running. This may seem surprising to many who assume it is not possible to gain these types of benefits from running simply because it is such a simple sport. However, there is some coordination involved in running. Trail running which involves running on unpaved trails especially requires a great deal of coordination. The uneven surface combined with obstacles such as rocks and tree roots can make trail running quite difficult. However, runners who regularly run on these types of services, quickly learn to maintain better control over their bodies to prevent tripping and stumbling while running. Even running on a flat surface which is paved can also result in improved coordination because it forces the body to work together to keep the runner upright and traveling in the correct path. Those who run regularly typically move more fluidly than those who do not run or engage in any type of regular exercise. 


Red blood cells carry oxygen from the lungs to all the cells of the body.
White blood cells are like soldiers protecting the body.
ARTERIES are vessels that carry blood away from the heart.
VEINS are vessels that carry blood back to the heart.
Blood CIRCULATES--circles--all around your body in about one or two minutes.
Inside the heart are four hollow chambers. Each chamber is a little pump. The pumping pushes blood all around your body.

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