Being 5280 feet in the air, athletes from all over the world travel to Denver to train and gain the upper hand. But how does this training work to improve athletic performance? The main goal of altitude training is to improve oxygen delivery. During the course of a competition, especially during an endurance event, the capacity of an athlete’s muscles to receive and consume oxygen exceeds the capacity the cardiovascular system can supply and it’s this gap between the amount of oxygen needed and what is actually available that aids to the decrease in performance and the onset of fatigue. Of course, this just wont due during a competition and so some athletes implement altitude training and improve the limitation of oxygen delivery by stimulating an increase in their total volume of red blood cells and hemoglobin mass (1). Being an athlete who trained in Denver to compete at sea level, I did see and increase in my performance during competitions but the benefits were short lived and needed to be rebuilt upon return to Denver after about a week or so at sea level.
But an increase in red blood cells isn’t the only benefit experienced by athletes. Recent studies have discovered that implication of altitude train can decrease the levels of free fatty acids, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol in individuals (2). Scientists have also found that the concentration of homocysteine, an amino acid which is implicated in coronary mortality, is reduced by 11% after altitude training (2). Combine these clinical benefits with the reduction in an individual’s maximal systolic blood pressure and it is possible that altitude training may be beneficial for patients with cardiovascular diseases (2).
Still, because altitude training requires the body to be deprived of an adequate supply of oxygen (hypoxia), it needs to be done with caution in order to prevent dangerous clinical problems such as acute mountain sickness, high-altitude cerebral edema, and high-altitude pulmonary edema (1). Observing known cases, the severity of these conditions depends on the altitude and, more importantly, the rate of ascent and the individual in particular (1).
So where is the balance between benefits and dangerous conditions? Also, being that the benefits are due to adaptation, I’m wondering if there are ways to prolong the results of altitude training and so improve the condition of cardiovascular disease patients.
(1)Rusko, H., Tikkanen, H., & Peltonen, J. (2004). Altitude and endurance training. Journal of Sports Sciences, 22(10), 928-944.
(2)Vogt, M., & Hoppeler, H. (2010). Is hypoxia training good for muscles and exercise performance?. Progress In Cardiovascular Diseases, 52(6), 525-533.
(image taking from AltiMax Simulated Altitude Training: www.altimaxtraining.com/technology)
I was born in a Mountain valley in Huancayo, Peru.I remembered that as a child I used to suffer from Mountain sickness also known as Soroche in my country. The mountain sickness happened usually when returning from a vacation trip of from Lima at sea level about 5,080 ft returning to my hometown at 10,692 ft above sea level. The symptoms of Soroche were persistent for couple of days, eventually went away. I did not experienced headaches or nausea as most visitors due, because I believed my lungs adapted to the atmospheric pressure. Growing up I noticed that the mild mountain sickness was vanishing.
ReplyDeleteI am not an athlete so I cannot really talk about training and endurance, but instead about the most common symptoms tourist experience when visiting high mountain places in Peru. One of the most common visit places is Cuzco at 10,800 ft. From our physiology knowledge at high elevations, the amount of oxygen in the atmosphere is the same as sea level percentage wise, but the barometric pressure reduces leading to a reduce of oxygen in the tissues also known as hypoxia. When individuals face this challenge they evolve an acclimatization process of which engaged the repspiratoty, circulatory, renal and nervous systems. The evolved mechanism work to normalize the amount of oxygen in the tissues. The peripheral chemoreceptor’s and nerve endings in the body serve as sensor of the amount of O2 that enter the blood stream. The nerve endings react to the amount of the change in oxygen pressure in the arterial blood and send the information to the brain area that controls cardiac cycle and breathing. The response to this stimulus is an increase in pulmonary ventilation for the first 3 to 5 days this process is called Ventilatory Acclimatization. Another response is the increase of adrenaline and nor-adrenaline in the bloodstream which leads to an increase of cardiac frequency.
The adaptive response to high elevations may lead to few side effect disorders such as pulmonary edema or brain edema. It is important to take in consideration that the process of acclimatization varies from person to person. Symptoms included of headache, nausea, insomnia, vertigo, continuous headaches, vomiting, difficult breathing, extreme fatigue and less urination. Most high elevation cities in Peru always recommend visitors to avoid strenuous physical activity, drink plenty of water and fluids, eat small portions of food and preferably high carbohydrates, stay warm and plenty of rest. Medication is available for Mountain sickness are Diamox and ibuprofen for headaches. It has nothing to do with previous physical training, or the number of times a person has been in high elevations.
Reference:
LeónVelarde F., Arregui A., MongeC C., and Ruiz H. (1993). Aging at high altitudes and the risk of chronic mountain sickness. J. Wild. Med. 4:183188.
High altitude training is a technique used among athletes but what actually causes the physiological shift in the body to lead to increased performance levels? A study about sports medicine analyzed the Hypoxia induced training technique (Berglund 1992). The author of the study concluded that the hypoxia which leads to higher levels of hemoglobin content can be obtained within three weeks of training. It is interesting though that you do not need to be at altitude to receive these effects. Hypoxico.com sells a variety of products that an athlete can use to simulate high altitude wherever you are. This is because the lower levels of oxygen in the blood are what stimulated the increased performance not the actual altitude. This was also proven in the New England journal of medicine as they discovered that smokers have shown similar results (Smith et al. 1978). This is because the smokers are starving themselves from oxygen as well as damaging lung tissue leading to the organ being less efficient. In turn this leads to the body needing to me more efficient in other ways in order to compensate, so the blood has heightened levels of hemoglobin and red blood cells. So it is the lack of oxygen that leads to the physiological changes that can affect performance in athletes when training.
ReplyDeleteJ. Robert Smith, M.D., and Stephen A. Landaw, M.D., Ph.D. (1978). Smokers' Polycythemia. N Engl J Med 1978; 298:6-1.
Berglund B (1992). High-altitude training. Aspects of haematological adaptation. Sports Medicine (Auckland, N.Z.) 14(5):289-303
http://www.hypoxico.com/?gclid=CLSV077_56wCFWgEQAod7SUZJQ
Currently, I’m taking a biochemistry course and our last test was all about hemoglobin. There are more benefits to high-altitude training than just higher red blood cell content! But first, let’s do an overview of hemoglobin. Hemoglobin is a protein that is made up of two α-β sub-units, each of which carries two heme groups. These sub-units shift 15 degrees when oxygen is bound. This causes a change in conformation. Hemoglobin has two conformations, tense and relaxed. These conformations each have different affinities for oxygen. In general, the more oxygen you bind to hemoglobin, the easier it is to bind the next oxygen. Hemoglobin’s binding sites for oxygen, or the heme group, is also capable of chelating one more group on the reverse face of the planar heme group (Voet and Voet, 2011). The equilibrium between the tense state and relaxed state can be seen as this:
ReplyDeleteT + O2 = RO2 (Since this blog won't accept symbols, pretend the equals sign is an equilibrium arrow)
The relaxed form of hemoglobin has a much higher affinity for oxygen.
2,3-BPG is pretty sweet stuff. It binds to the reverse side of the planar heme group and stabilizes the T-state, or decreases the hemoglobin’s affinity for oxygen. After just 2 days at higher elevations, this BPG level is rising by 55 μg phosphorus • mL-1 blood!! This increases the oxygen needed for hemoglobin saturation by about 7 torr (Voet and Voet, 2011). While this seems like a bad thing, don’t worry. The partial pressure of oxygen in our lungs is plenty high enough to account for this change. All that this shift in saturation levels does is to make the delivery of oxygen more efficient to the tissues.
Voet and Voet (2011). Hemoglobin: Protein function in microcosm (Ed 4), Biochemistry (pp. 323-358). United States of America: John Wiley & Sons.