What would an athlete have to consider if he were to compete at an area of high altitude?(regarding breathing)

Question

thanks for all the answ3rs if any...

Answer 1

Symptoms associated with high altitude sickness result from the body's inability to adjust to lower levels of oxygen in the blood. At sea level, the concentration of oxygen is about 21% and the barometric pressure averages 760 mmHg. As altitude increases, oxygen concentration remains the same but the number of oxygen molecules per breath is reduced due to lower barometric pressure. At 3,658 meters (12,000 feet), barometric pressure decreases to 483 mmHg, resulting in roughly 40% fewer oxygen molecules per breath.



In order to increase oxygen levels in the blood, your body responds by breathing faster. Although oxygen levels increase, sea level concentrations cannot be reached. The body must adjust to having less oxygen. This adjustment is called acclimatization. At elevations above 5,500 meters, acclimatization is not possible and the body begins to deteriorate



An individual's initial response to the lowered oxygen tension at high altitude is to increase ventilation, by increasing the rate and volume of breaths. This phenomenon, the hypoxic ventilatory response, varies between individuals. Clinical studies have shown that those individuals with a history of AMS (acute mountain sickness) have a diminished ventilatory response to simulated altitude exposure, as manifest by lower minute ventilation and higher arterial carbon dioxide, despite low transcutaneous oxygen saturation. In contrast, those who remain asymptomatic upon acute exposure to altitude have a high hypoxic ventilatory response. The mechanism for this process remains unclear.


As extremes of altitude are reached, the normal lung faces additional impediments in transferring oxygen to the blood. A non-uniform pulmonary arterial vasoconstriction has been demonstrated by using scintigraphy scanning with radiolabeled particles to evaluate the relationship of lung ventilation with pulmonary perfusion. This effect becomes apparent at 3,000 meters. Increasing exercise at this same altitude is also associated with an increasing limitation for the diffusion of oxygen across the alveolar-capillary membrane. At an elevation of 3,900 meters, the unacclimatized individual consumes more oxygen with the increased work of breathing than is gained by that additional ventilation.


There are clear pulmonary conditioning benefits from exercise at intermediate altitude. A greater metabolic efficiency is suggested by a 20% reduction in an individual's oxygen utilization with the same maximal exercise upon return to sea level after intermediate altitude conditioning. Hemoglobin saturation is achieved with lower partial pressures of oxygen and blood levels of 2,3-diphosphoglycerate are elevated after intermediate altitude conditioning. The ability of hemoglobin to carry oxygen to the tissues is further enhanced by the increase in the number of red blood cells


Above 10,000 feet (3,000 meters) most people experience a periodic breathing during sleep known as Cheyne-Stokes Respirations. The pattern begins with a few shallow breaths and increases to deep sighing respirations then falls off rapidly. Respirations may cease entirely for a few seconds and then the shallow breaths begin again. During the period when breathing stops the person often becomes restless and may wake with a sudden feeling of suffocation. This can disturb sleeping patterns, exhausting the climber. Acetazolamide is helpful in relieving the periodic breathing. This type of breathing is not considered abnormal at high altitudes. However, if it occurs first during an illness (other than altitude illnesses) or after an injury (particularly a head injury) it may be a sign of a serious disorder.