Every year travel becomes easier, faster, and the world becomes a little smaller. Because of this, more and more people are traveling to unfamiliar lands. For those who have lived their entire lives near sea level, a high altitude location can be a shock to the body. What happens to the air at higher altitudes, and what effects does it have on the body? Can taking the proper precautions to minimize the negative effects?
Air at Sea Level vs. High Altitude
The air we breathe is composed mainly of nitrogen and oxygen, and the percentages of each remain constant regardless of whether you are at sea level or high altitude. However, the higher the altitude, the lower the partial pressure of oxygen in the air. Partial pressure refers to the number of oxygen molecules in any given amount of air. At sea level, the partial pressure of oxygen is 159mmHg. At the summit of Mount Everest (8848m), the partial pressure drops to 53mmHg.
Think of it this way: less pressure at higher altitudes means that oxygen molecules are further apart since there is less pressure pushing them close together. The result is that in any given volume of air, there are fewer oxygen molecules. In each breath, less oxygen is inhaled.
Effects of High Altitude on the Body
As you start increasing in altitude, the pressure starts to drop, and you try to breathe more to compensate for the lack of oxygen. Even so, there is less oxygen in your system, and less oxygen reaching your muscles. Your physical performance won’t be at its peak, and you may find that you get tired much more easily than at sea level.
Your body loses more water at higher altitudes, which can result in dehydration. The humidity is lower and sweat evaporates quicker. The strain of high altitude on your muscles can result in increased perspiration, and more water needs to be drunk to counteract the effects of dehydration. High altitude can also boost metabolism and suppress your appetite, so you’ll need to actively try to eat enough food to maintain energy levels.
After being exposed to higher altitudes for a few days, the body begins to acclimate. Studies have found that hemoglobin levels in the blood (the protein in the blood responsible for carrying oxygen throughout the body) increase after as little as one day at high altitude. Although you are still getting less oxygen overall, your body has become better adapted to distributing that oxygen. 1
Who Does Altitude Sickness Affect?
Anyone can feel the effects of altitude sickness, regardless of their fitness level. The only exceptions are people who are native to areas of high altitude. These people have been shown to have larger lung capacities as well as higher efficiency of oxygen transport throughout body tissues. This remains true both at rest and throughout physical activity.
Those who haven’t lived their whole lives above 8000 feet are all equally as susceptible to the effects of altitude sickness. In minor cases, the symptoms may include headache, dizziness, lethargy, nausea, and trouble sleeping. These symptoms can appear anywhere between 6 and 48 hours after ascending over 8000 feet. In more severe cases of altitude sickness, fluid can build up in the lungs or brain and can be life-threatening. Symptoms of more severe forms of altitude sickness include loss of coordination and a severe headache. They also include tightness in the chest, confusion, shortness of breath even at rest, a cough that produces a frothy substance and the inability to walk.
Your chances of getting altitude sickness depends on a variety of factors. These include how quickly you ascend, what the altitude is where you sleep, and the altitude where you generally reside. If you feel as though you are experiencing symptoms of altitude sickness, you should aim to decrease your altitude as quickly as possible. Seek medical assistance if your symptoms get worse.
How Can You Prevent Altitude Sickness?
One of the best ways to prevent symptoms of altitude sickness is to gradually acclimate your body to higher altitudes. If you’re able to run a mile in under 10 minutes at sea level, your body likely won’t be able to run the same mile at a high altitude. Don’t over-exert yourself, and don’t overestimate your capabilities. It is best to let your body acclimate to the higher altitude for at least a day before participating in any sort of physical activities. If you plan on continuing to increase your altitude after the first day, you should do so slowly. After 8000 feet, you should only increase up to 1000 feet a day. Every few days, give yourself a rest day to help your body acclimate properly.
When hiking or climbing at high altitudes, you should drink double the amount of water you do at sea level. The risk of dehydration is high, and you may not even realize you aren’t getting the water you need. You should also avoid smoking or drinking alcohol, as these can leave you at a higher risk for altitude sickness. A diet high in carbohydrates is recommended to ensure you are supplying your body with enough energy. 2
What About Returning To Lower Altitudes?
The effects of high altitude get a lot of press, but the effects of returning to a lower altitude aren’t as well documented. Is there such a thing as ‘reverse altitude sickness’? If you’re heading to the mountains on a week-long vacation, you likely won’t feel any negative effects when returning home. However, if you spend 6 months to a year or more at a very high altitude, you may feel some symptoms of de-acclimatization upon returning. In one study, 84.36% of individuals who had lived in Tibet for 10-20 years had symptoms. These symptoms included headache, fatigue, lethargy, insomnia, memory loss, fidgetiness and more. 3
When changing altitudes, the best way to deal with the change is to let your body slowly acclimate. You can do this by staying hydrated, maintaining a healthy diet, and not overexerting yourself. This way, you can enjoy the mountain air, the sea breeze, and everything in-between.
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