Exercise and hypoxia are often linked for reasons related to altitude. Hypoxia is a condition in which the brain is deprived of oxygen for any amount of time. This can happen as a side effect of exercising strenuously in a high altitude environment, in which there is less oxygen available in the atmosphere than at lower altitudes.
Hypoxia can occur any time an oxygen supply is low, even though there is an adequate amount of blood flowing to the brain. Tremors, memory loss, inattentiveness, and unconsciousness can accompany this state. If an individual is not revived within minutes of experiencing unconsciousness due to hypoxia, brain death can occur quickly. Life saving medical equipment, such as an external oxygen supply or a blood transfusion, is typically required to revive individuals suffering from this condition.
When the human body performs physical work, it requires additional amounts of oxygen to be pumped throughout the body. This oxygen is then utilized to maintain brain functions, improve muscle functioning and coordination, and provide stamina, among other activities. As someone exercises, they may notice that their breathing becomes deeper or their breaths come faster together. These reactions are automated responses on the part of the lungs and nervous system, designed to pump oxygen into the blood quickly to be delivered throughout the body.
High altitude elevations have less oxygen in the atmosphere than lower altitude elevations. An individual exercising in a normal altitude environment, for example, at sea level, will have access to enough oxygen in the air to adequately supply his body as it works. The same work out performed in a high altitude environment, however, can cause that person to experience the early symptoms of hypoxia. As his body performs work, and his lungs pump more air into his blood stream, that air has less oxygen available than it did at sea level. The harder he works, the less oxygen becomes available to his brain until either he ceases exercising or the oxygen supply momentarily stops.
This potentially dangerous link between exercise and hypoxia can be experienced by anyone, regardless of their physical condition. The lack of oxygen to the brain which causes the memory lapses, odd behavior, and black outs is usually not related to whether a person is physically fit. The human body requires a certain amount of oxygen to be present in the blood stream to maintain normal brain functions. Those who are physically fit and active can experience hypoxia in high altitude situations as quickly as those who are not.
The body can adapt itself over time to these lower oxygen environments and prevent the negative side effects related to exercise and hypoxia. Those who move to high altitudes should give their body time to adjust to the new atmosphere for several weeks before attempting any strenuous work outs. The body learns to conserve oxygen and use it more efficiently, so that those who live continuously in these types of environments are not constantly in danger of experiencing hypoxia. Individuals preparing for a brief trip into a high altitude climate, like climbers preparing to scale a new mountain, typically acclimate themselves slowly to the changing air around them.
These athletes may spend as long as a month at different elevations on the side of the mountain, allowing their bodies to adjust, before moving forward. They have been trained to react to hypoxia symptoms by slowing down and giving their bodies time to acclimate to their new conditions. They may also carry additional oxygen tanks with them, in case of emergency, and for possible use as they reach the summit.