Have you ever experienced breathlessness while exercising and training? Why do I breathe so heavily during exercise? What can be done to improve your breathing during exercise?
I want to explain some physiological terms and reasons that will help you understand why you get breathless during exercise. Firstly during exercise and ordinary living air that enters your lungs is termed inspiration and air that leaves your lungs is termed expiration. In order for both these processes to occur there has to be a positive pressure gradient, which happens when air moves from a high pressure to a lower pressure. So when inspiration occurs, the partial pressure of oxygen in the atmosphere is greater than the partial pressure of oxygen within the lungs. Therefore the oxygen moves into the lungs, and from the lungs it moves into the bloodstream because the partial pressure of oxygen within the lungs is greater than the partial pressure within the blood. The oxygen within the bloodstream then enters the muscles and tissues due to a positive pressure gradient. Obviously when we breathe out we don’t expire oxygen but instead we expire carbon dioxide. Carbon dioxide moves outside the body cells and into the capillaries and then from there it moves into the lungs and is expired through the mouth.
Another very important aspect is hemoglobin protein that is found within the blood cells. About 98% of oxygen is transported in the blood bound to hemoglobin. The affinity of oxygen to the hemoglobin depends on the partial pressure of oxygen within the blood. At very high partial pressure of oxygen like those found in the lungs results in the hemoglobin being saturated with the oxygen molecules. This is due to the fact that there is already a great amount of oxygen within the lungs. So hemoglobin does not need to unload much oxygen there. On the opposite spectrum low partial pressures of oxygen like those found at tissue level results in a great unloading of oxygen from hemoglobin. This is because at the tissue level the cells need great amounts of oxygen to function. Obviously during exercise this will change and greater amounts of oxygen will need to be delivered to the functioning tissues. During exercise the muscle temperature increases and blood ph levels drop. Both of these factors affect the affinity of oxygen to hemoglobin. These factors both result in more oxygen being unloaded at tissue and muscle level due to the fact that the partial pressure drops.
Have you ever wondered why you breathe so heavily after exercise or even walking fast up a flight of steps? This is termed EPOC (excess postexercise oxygen consumption) and can explain the reason for heavy breathing after exercise. When you start aerobic exercise your oxygen consumption takes several minutes to reach steady state and so the aerobic energy system doesn’t function immediately. So in order to generate energy for the working muscles the body has to rely on the anaerobic pathways to produce ATP. So therefore an oxygen deficit takes place during the first stage of exercise. At the end of exercise your breathing remains elevated for some time. This is because during the initial stage of exercise some oxygen was borrowed from hemoglobin and now at the end of the exercise it has to be replenished. The respiration also remains elevated during this time of recovery to get rid of the excess carbon dioxide that is formed as a by product during the anaerobic pathways. Also the muscle temperature is increased resulting in the respiration and metabolism remaining high.
If we put all of these physiological factors together we will be able to determine why we breathe so heavily during exercise. When you start exercising your muscle temperature increases and your blood ph level drops. This results in a build up of carbon dioxide within the blood stream and muscles causing the oxygen hemoglobin curve to shift to the left resulting in oxygen being delivered to the working cells at lower partial pressures. Due to this fact there will be less oxygen returning through the system to be delivered to the active areas, and there will be greater concentrations of carbon dioxide in the system. In order to overcome this imbalance the respiratory muscles will contract at a quicker rate so that they can speed up respiratory inspiration and expiration. During the inspiration phase the lungs will try to bring in more oxygen from the atmosphere, while during the expiration phase the lungs will be getting rid of the excess carbon dioxide. So basically the heavy breathing during exercise is a result of your muscles not being able to get enough oxygen to them, and also not being able to buffer the build up of carbon dioxide. Another reason for this could be that your body is using anaerobic pathways in order to produce energy during exercise. The heavy breathing will continue during exercise and slightly afterwards due to EPOC as explained previously.
What I suggest is that before you begin exercising to go for a light jog to almost get the muscles and the aerobic system ready for what is to follow. This will ensure that the muscles know what to expect and don’t have to take drastic measures when the intensity during the exercise is increased.
Trevor Court
Friday, March 26, 2010
Friday, March 19, 2010
GI - The Glycemic Index
Everyone loves to tell you all about low GI foods, because it slowly releases energy, "it'll last longer". Which is in fact true, it does release it slowly, but what exactly does it mean, and is it always good to eat low GI foods..? Do you know which foods are low GI..? While reading the article, try thinking about foods that you know as low GI, and I will include a list at the end.
The glycemic index is used to classify foods in terms of how long they raise the blood glucose levels. The reference point on the GI scale is white bread, which has a reading of 100 on the glycemic index. Foods that have a high GI are digested quickly, they raise blood glucose rapidly and also stimulate high insulin levels (insulin aids in transporting glucose from the blood to the muscle). The exact opposite is true for lower GI foods.
Now contrary to popular belief, sugars do not always rank as higher on the scale when compared to starches. Potatoes and table rice, rank higher than normal table sugar (sucrose) also, many things can affect the GI of a particular food (cooked/uncooked, processing, is it part of a meal or a snack on its own etc…?). So although the GI of a food is important, it is not a perfect way of analyzing your diet.
Studies have been shown that low GI foods increase exercise performance (Demarco et al.) but other studies have shown no difference between eating low/high GI foods before exercise/competition (Wee et al) (Thomas et al). So if your interest is when to eat certain foods before/after/during events, try experimenting a bit as more research needs to be done on the glycemic index with regards to exercise performance.
Glycemic index of certain foods:
White Bread 99
Sponge Cake 66
Corn Flakes 116
Oats 78
White Rice 91
Brown Rice 79
Linguine (pasta) 70
Milk (full cream) 38
Honey 78
Sucrose (sugar) 97
Apple 57
Banana 74
Orange 60
Potato (baked) 121
Peanuts 21
Yoghurt (sweetener) 20
(Baechle TR, Earle RW, essentials of strength training and conditioning, 2008)
JJ
The glycemic index is used to classify foods in terms of how long they raise the blood glucose levels. The reference point on the GI scale is white bread, which has a reading of 100 on the glycemic index. Foods that have a high GI are digested quickly, they raise blood glucose rapidly and also stimulate high insulin levels (insulin aids in transporting glucose from the blood to the muscle). The exact opposite is true for lower GI foods.
Now contrary to popular belief, sugars do not always rank as higher on the scale when compared to starches. Potatoes and table rice, rank higher than normal table sugar (sucrose) also, many things can affect the GI of a particular food (cooked/uncooked, processing, is it part of a meal or a snack on its own etc…?). So although the GI of a food is important, it is not a perfect way of analyzing your diet.
Studies have been shown that low GI foods increase exercise performance (Demarco et al.) but other studies have shown no difference between eating low/high GI foods before exercise/competition (Wee et al) (Thomas et al). So if your interest is when to eat certain foods before/after/during events, try experimenting a bit as more research needs to be done on the glycemic index with regards to exercise performance.
Glycemic index of certain foods:
White Bread 99
Sponge Cake 66
Corn Flakes 116
Oats 78
White Rice 91
Brown Rice 79
Linguine (pasta) 70
Milk (full cream) 38
Honey 78
Sucrose (sugar) 97
Apple 57
Banana 74
Orange 60
Potato (baked) 121
Peanuts 21
Yoghurt (sweetener) 20
(Baechle TR, Earle RW, essentials of strength training and conditioning, 2008)
JJ
Monday, March 15, 2010
Core Gymnastics: The Rings
We have all watched gymnastics, particularly the rings at some time on our lives and wondered, how on earth do they do it, how are they so strong and we stare in awe at the unbelievable strength and bodies these guys possess. It has to be noted that these specialized gymnasts are strong all over and strength train all the muscles of their body. Now what makes them so strong, in particular, lets look at the anatomy of it...
Firstly a gymnast has to have an extremely strong base and core to stabilize the body and keep swaying and movement to a minimum. By the core, I am referring to the following muscles, some which you may not know as "core" muscles as such. Muscles of the abdomen: Rectus abdominis, Transversus abdominis, internal/external obliques. Back: Erector Spinae group, Quadratus lumborum. Hip: Hip flexors (iliopsoas), Gluteal group (maximus, medius and minimus). All these muscles provide stabilization of the joints and stabilization of the trunk. Some muscles which are generally noted as prime movers, also act is stabilizers such as the gluteal group and hip flexors. Core training can be done through various methods generally involving controlled movement on unbalanced surfaces. For example a side bridge with shoulder and leg abduction, the core works hard to stabilize the bodies joints for a controlled slow movement to occur in the shoulder and hip joint as the body remains still.
Secondly the muscles of the shoulder girdle. Obviously in the rings, all the muscles of the body work hard, but the muscles that make up the shoulder complex and the muscles that act on the shoulder joint all play a massive role. Firstly the Pectoral region. Pectoralis major and pectoralis minor. The pec major mainly adducts (as in dumbbell fly's) and rotates the arm medially (inwards). Secondly the deltoids, abducts, extends, flexes arm (moves arm forward, backward and sideways away from the body). Thirdly the Triceps Brachii (extends the forearm at the elbow). Also the Latissimus dorsi (extends, adducts, rotates arm medially). These muscles jump out at us as the strong, prime movers in the main action of gymnastic rings. The first two on the shoulder joint and the third on the elbow, and the latter on the shoulder and scapula. But not to be overlooked are the stabilizing muscles in the performing of ring exercises. To start there is the serrarus anterior. This muscle connects the ribs to the scapular, it is a broad thin muscle that can move the scapula down and anteriorly but mainly assists in stabilizing the scapula through a range of movements. The rotator cuff group (supraspinatus, infraspinatus, teres minor and subscapularis). This group also moves the humerus in the shoulder joint through external and internal rotation as well as abduction, but also mainly stabilizes and assists the larger muscle groups through all movements. The Trapezius muscle (all fibres) and the two Rhomboid groups (major and minor), also assist in movement of the scapula and the trapezius also acts as a stabilizer of the scapula. The biceps brachii also will aid in stabilization of the shoulder and elbow joints.
So after all this what am i saying..?
Many people can be strength trained for the rings by just training on the rings, but what little bit extra can be done..? And what else other than strengthening of the large groups can be done..?
It comes down to those stabilizers. Now other than training on the rings, additional strength training needs to be done in the gym, but how..? Firstly, barbells must be replaced with dumbbells. Using dumbbells aids in recruitement of the stabilizers of the shoulder girdle and increased stabilizer strength leads to increased prime mover strength. So dumbbell press as opposed to flat bench press would help. Secondly performing normal exercises such as dumbbell curls at differing angles, such as at 30 degrees lateral rotation would increase rotator cuff involvement. Also performing exercises on medicine balls/physio balls or balance boards to increase proprioception (relative awareness of limb position) and greatly increase strength of the stabilizers such as the serratus anterior and rotator cuff group (plyometric push ups on a medicine ball, push ups on balance boards etc...). Using thera bands for the rotator cuff group is also a possible strength aid.
So in addition to simple, standard strength training exercises, simple stabilization added exercises need to be performed to increase performance that little extra.
Here are some links with regards to anatomy and exercises...
http://exrx.net/Lists/ExList/ChestWt.html#anchor682036
http://familydoctor.org/online/famdocen/home/healthy/physical/injuries/265.html
http://www.shoulder-pain-management.com/shoulderrotatorcuffexercises.html
http://www.changingshape.com/exercise/musclecharts/
JJ
Firstly a gymnast has to have an extremely strong base and core to stabilize the body and keep swaying and movement to a minimum. By the core, I am referring to the following muscles, some which you may not know as "core" muscles as such. Muscles of the abdomen: Rectus abdominis, Transversus abdominis, internal/external obliques. Back: Erector Spinae group, Quadratus lumborum. Hip: Hip flexors (iliopsoas), Gluteal group (maximus, medius and minimus). All these muscles provide stabilization of the joints and stabilization of the trunk. Some muscles which are generally noted as prime movers, also act is stabilizers such as the gluteal group and hip flexors. Core training can be done through various methods generally involving controlled movement on unbalanced surfaces. For example a side bridge with shoulder and leg abduction, the core works hard to stabilize the bodies joints for a controlled slow movement to occur in the shoulder and hip joint as the body remains still.
Secondly the muscles of the shoulder girdle. Obviously in the rings, all the muscles of the body work hard, but the muscles that make up the shoulder complex and the muscles that act on the shoulder joint all play a massive role. Firstly the Pectoral region. Pectoralis major and pectoralis minor. The pec major mainly adducts (as in dumbbell fly's) and rotates the arm medially (inwards). Secondly the deltoids, abducts, extends, flexes arm (moves arm forward, backward and sideways away from the body). Thirdly the Triceps Brachii (extends the forearm at the elbow). Also the Latissimus dorsi (extends, adducts, rotates arm medially). These muscles jump out at us as the strong, prime movers in the main action of gymnastic rings. The first two on the shoulder joint and the third on the elbow, and the latter on the shoulder and scapula. But not to be overlooked are the stabilizing muscles in the performing of ring exercises. To start there is the serrarus anterior. This muscle connects the ribs to the scapular, it is a broad thin muscle that can move the scapula down and anteriorly but mainly assists in stabilizing the scapula through a range of movements. The rotator cuff group (supraspinatus, infraspinatus, teres minor and subscapularis). This group also moves the humerus in the shoulder joint through external and internal rotation as well as abduction, but also mainly stabilizes and assists the larger muscle groups through all movements. The Trapezius muscle (all fibres) and the two Rhomboid groups (major and minor), also assist in movement of the scapula and the trapezius also acts as a stabilizer of the scapula. The biceps brachii also will aid in stabilization of the shoulder and elbow joints.
So after all this what am i saying..?
Many people can be strength trained for the rings by just training on the rings, but what little bit extra can be done..? And what else other than strengthening of the large groups can be done..?
It comes down to those stabilizers. Now other than training on the rings, additional strength training needs to be done in the gym, but how..? Firstly, barbells must be replaced with dumbbells. Using dumbbells aids in recruitement of the stabilizers of the shoulder girdle and increased stabilizer strength leads to increased prime mover strength. So dumbbell press as opposed to flat bench press would help. Secondly performing normal exercises such as dumbbell curls at differing angles, such as at 30 degrees lateral rotation would increase rotator cuff involvement. Also performing exercises on medicine balls/physio balls or balance boards to increase proprioception (relative awareness of limb position) and greatly increase strength of the stabilizers such as the serratus anterior and rotator cuff group (plyometric push ups on a medicine ball, push ups on balance boards etc...). Using thera bands for the rotator cuff group is also a possible strength aid.
So in addition to simple, standard strength training exercises, simple stabilization added exercises need to be performed to increase performance that little extra.
Here are some links with regards to anatomy and exercises...
http://exrx.net/Lists/ExList/ChestWt.html#anchor682036
http://familydoctor.org/online/famdocen/home/healthy/physical/injuries/265.html
http://www.shoulder-pain-management.com/shoulderrotatorcuffexercises.html
http://www.changingshape.com/exercise/musclecharts/
JJ
Best Time of the Day to Exercise?
You may have noticed the poll we had running this last week or so. Is there science behind the results/preferences of when people prefer to train and exercise? Are certain times of the day better or worse than others? How much do psychological factors, rather than physical reasons, effect when people hit the gym?
There’s pros and cons both ways with regards to AM versus PM exercise and there are a lot of factors that influence specific exercise and its benefits (eg. nutrition, time). Everybody is effected in many ways by a “body clock” / circadian rhythm. This is an important mechanism for hormone release, activation of electrical activity in muscle, etc. This will have an effect on peoples’ exercise and training times. For example, many elderly folks prefer to exercise early in the morning, as they rise earlier, with an altered circadian rhythm and sleep patterns.
Mornings are generally better for exercise when trying to lose weight. One advantage of morning exercise is an elevated Resting Metabolic Rate (metabolism) through the day. This is accompanied by a phenomenon known as EPOC (Excess Post-exercise Oxygen Consumption) which can promote further fat loss over time. People that exercise in the morning also tend to have higher levels of adherence to exercise/training programs. Many ‘early birds’ also feel their mood is improved from the start of their day.
Some of us just aren’t “morning people” though and should rather find a time of day that we feel better about exercising. Mornings are also often accompanied by lower blood glucose, not so good for any weight/anaerobic training. Injuries are more common with morning training; body temperature is lower, flexibility is decreased and co-ordination with complex exercise techniques will be affected. Morning exercise has been shown to have a slightly higher risk of heart attack or stroke.
Two hormones that play a roll in exercise are Cortisol and Testosterone. Cortisol, a catabolic (breakdown) hormone, is highest within the body in the morning and decreases throughout the day. Testosterone, the main anabolic (build up) hormone, reaches its highest levels, relative to Cortisol, in the afternoon/evening.
Studies have shown that maximal strength reaches highest levels only after midday, with anaerobic and endurance ability peaking in the afternoon. This links with the higher anabolic hormone (Testosterone and Growth Hormone) state within the body to make afternoon/evening exercise slightly better for endurance, muscle mass and strength training. Body temperature rises steadily throughout the day, which makes sports performance generally better during late afternoon/evening. Exercise, especially at gyms, does tend to be more social in the afternoon and evenings too.
Exercising regularly in the PM does tend to be more difficult to maintain for some people as work commitments or distractions can interfere, although dealing with the day’s stress can be an added benefit of exercising at this time. Sleep is not generally affected by exercise, so evening exercise should be fine for most people.
Remember though, any exercise is better than no exercise at all.
Jed
Friday, March 5, 2010
The Importance of Interval Training for Cyclists
What increases the performance of a cyclist? Is it all about doing lots of mileage at slow speeds, or is it about doing interval training? That's the question that every cyclist asks themselves when it comes to seeing the best results. Obviously we know that cycling is an endurance sport that focuses mainly on the breakdown of fatty acids to convert them into energy for our muscles to utilize. But is there a more efficient way of training that will help cyclists to be able to ride and race at higher intensities without fatiguing so soon. Are you doing the wrong sort of training?
Many cyclists overlook the importance of interval training because they think that in order to ride and perform better they just need to ride for longer durations. In a recent study that I've read by (Kirsten A. Burgomaster et al.) they suggest that by only doing short sprint intervals for two weeks you will be able to see greater physiological changes that will improve your performance. In this study there was a greater increase in the oxidative enzyme called citrate synthase which is a good indicator of aerobic performance. The main adaptations that occur during aerobic training are the development of the mitochondria which help deliver energy to the working muscles and an increase in the number of capillaries within the exercising muscles. A trend with endurance training over a number of months has shown an increase in VO2max to a certain degree until it eventually plateaus, whereas the oxidative enzymes within the mitochondria continue to rise. The changes to the mitochondria that are brought on by training result in something called glycogen sparing, which is the sparing of glycogen as an energy source and instead breaking down fats at higher intensities. This would obviously result in the muscles being able to produce energy at a higher intensity while being able to minimize the amount of by products such as lactate that hinder the muscles from functioning properly at that given intensity.
If you're stuck in the same place in terms of training and improving, and you feel that you aren't going anywhere, give interval training a bash and see the results for yourself. Sometimes it's good to break routine and do something that might stress the muscles in a different way. Don't take my word for it, get on the bike and do it yourself.
Trevor
Many cyclists overlook the importance of interval training because they think that in order to ride and perform better they just need to ride for longer durations. In a recent study that I've read by (Kirsten A. Burgomaster et al.) they suggest that by only doing short sprint intervals for two weeks you will be able to see greater physiological changes that will improve your performance. In this study there was a greater increase in the oxidative enzyme called citrate synthase which is a good indicator of aerobic performance. The main adaptations that occur during aerobic training are the development of the mitochondria which help deliver energy to the working muscles and an increase in the number of capillaries within the exercising muscles. A trend with endurance training over a number of months has shown an increase in VO2max to a certain degree until it eventually plateaus, whereas the oxidative enzymes within the mitochondria continue to rise. The changes to the mitochondria that are brought on by training result in something called glycogen sparing, which is the sparing of glycogen as an energy source and instead breaking down fats at higher intensities. This would obviously result in the muscles being able to produce energy at a higher intensity while being able to minimize the amount of by products such as lactate that hinder the muscles from functioning properly at that given intensity.
So now that you know that pure endurance training has its limitations in terms of VO2max. We can see that there is a place for interval training, and that it plays an important role in increasing the mitochondria's functional capacity. Interval training also helps the muscles to function at a higher intensity without completely depleting the muscle glycogen stores. There is a place for long endurance training, because you have to ensure that your VO2max has reached its ceiling level, but you won't see the same results if you just do endurance training without doing short intense intervals. During the off season or base as it's termed in cycling, the cyclist can implement short intervals into their training program. They just have to perform very short intervals once or twice a week for a few weeks.
If you're stuck in the same place in terms of training and improving, and you feel that you aren't going anywhere, give interval training a bash and see the results for yourself. Sometimes it's good to break routine and do something that might stress the muscles in a different way. Don't take my word for it, get on the bike and do it yourself.
Trevor
Thursday, March 4, 2010
EPO: The Blood Booster
Doping with EPO (Erythropoietin) seems to have begun in the 1980’s with competitive endurance athletes and The World Anti-Doping Agency (WADA) placed it on its list of banned substances in 1990. A reliable and valid detection test developed by French scientists was adopted and implemented in time for the 2000 Olympic Games. This performance enhancing substance has been linked to sudden deaths of athletes and many doping scandals over the years.
Erythropoietin is a naturally occurring hormone, which is produced by the kidneys. It stimulates the bone marrow to produce more red blood cells (RBC’s). This therefore increases the heamatocrit (non-liquid element of blood) and heamoglobin (oxygen carrying chemical) levels of blood. It was first developed as a drug to treat anemia, kidney failure and post-surgery blood loss. It can also be used to assist recovery from chemotherapy and deal with complications of HIV/Aids.
By raising the amount of red blood cells in the blood, the potential to transport oxygen around the body is increased. This improves energy production, especially through the aerobic/endurance energy system, which decreases the use of the anaerobic/short-term energy system, levels of lactate and fatigue. The marker for physical fitness / aerobic capacity, VO2 max, is then increased. Studies have shown time to fatigue/exhaustion (exercise tolerance) can be extended by up to 17% while taking EPO!
But it’s not all good. The increased heamatocrit/RBC levels causes hyperviscosity of the blood (excess density). Some side effects can include raised blood pressure, dehydration, nausea, lethargy, fever and seizures. This thicker blood can increase chance of heart attacks and stroke, as the cardiovascular system is overloaded. Often, once the drug is abused, the amount of RBC production that will actually take place becomes hard to predict, adding to the risks involved. In recent years, in addition to more extensive and accurate testing, some sporting codes have set up safety cut off levels of heamatocrit (50%), although this has been seen as unsuitable, as ‘normal’ levels of heamatocrit vary greatly from person to person.
The most well-known incident of EPO use in sport occurred around the 1998 Tour de France, when the Festina cycle team was found with large quantities of EPO and other banned substances during the 17th stage. Other high profile cases of EPO doping include two cross-country skiers at the 2002 Winter Olympics, an female Ironman World Champs silver medallist and a double cross-country world champion. Along with the laboratory manufactured versions of EPO, newer advanced bone marrow stimulating chemicals/drugs are being developed, such as CERA (Continuous Erythropoiesis Receptor Activator). This modern option for doping has a unique action on bone marrow that differs slightly to EPO and it’s effects can last longer inside the body. A test for CERA was a surprise addition to the 2008 Tour de France and later two-time stage winner Stefan Schumacher was found guilty of doping. In 2009 the International Olympic Committee (IOC) declared that it was to re-test blood and urine samples from the Beijing Summer Olympics for CERA and in November of last year, the Olympic 1500m champion Rashid Ramzi was stripped of his gold medal after testing positive.
Here’s a few links that you might find interesting:
WADA – http://www.wada-ama.org/en/
Doping Cases - http://en.wikipedia.org/wiki/List_of_doping_cases_in_sport
Jed
Erythropoietin is a naturally occurring hormone, which is produced by the kidneys. It stimulates the bone marrow to produce more red blood cells (RBC’s). This therefore increases the heamatocrit (non-liquid element of blood) and heamoglobin (oxygen carrying chemical) levels of blood. It was first developed as a drug to treat anemia, kidney failure and post-surgery blood loss. It can also be used to assist recovery from chemotherapy and deal with complications of HIV/Aids.
By raising the amount of red blood cells in the blood, the potential to transport oxygen around the body is increased. This improves energy production, especially through the aerobic/endurance energy system, which decreases the use of the anaerobic/short-term energy system, levels of lactate and fatigue. The marker for physical fitness / aerobic capacity, VO2 max, is then increased. Studies have shown time to fatigue/exhaustion (exercise tolerance) can be extended by up to 17% while taking EPO!
But it’s not all good. The increased heamatocrit/RBC levels causes hyperviscosity of the blood (excess density). Some side effects can include raised blood pressure, dehydration, nausea, lethargy, fever and seizures. This thicker blood can increase chance of heart attacks and stroke, as the cardiovascular system is overloaded. Often, once the drug is abused, the amount of RBC production that will actually take place becomes hard to predict, adding to the risks involved. In recent years, in addition to more extensive and accurate testing, some sporting codes have set up safety cut off levels of heamatocrit (50%), although this has been seen as unsuitable, as ‘normal’ levels of heamatocrit vary greatly from person to person.
The most well-known incident of EPO use in sport occurred around the 1998 Tour de France, when the Festina cycle team was found with large quantities of EPO and other banned substances during the 17th stage. Other high profile cases of EPO doping include two cross-country skiers at the 2002 Winter Olympics, an female Ironman World Champs silver medallist and a double cross-country world champion. Along with the laboratory manufactured versions of EPO, newer advanced bone marrow stimulating chemicals/drugs are being developed, such as CERA (Continuous Erythropoiesis Receptor Activator). This modern option for doping has a unique action on bone marrow that differs slightly to EPO and it’s effects can last longer inside the body. A test for CERA was a surprise addition to the 2008 Tour de France and later two-time stage winner Stefan Schumacher was found guilty of doping. In 2009 the International Olympic Committee (IOC) declared that it was to re-test blood and urine samples from the Beijing Summer Olympics for CERA and in November of last year, the Olympic 1500m champion Rashid Ramzi was stripped of his gold medal after testing positive.
Here’s a few links that you might find interesting:
WADA – http://www.wada-ama.org/en/
Doping Cases - http://en.wikipedia.org/wiki/List_of_doping_cases_in_sport
Jed
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