Degrees of High Altitude
High - 5,000 to 11,500 ft
Very High - 11,500 to 18,000 ft
Extreme - above 18,000 ft
Note: Oxygen levels fall from 100%
at sea level to 32% at 30,000 ft
What Causes Altitude Sickness?
Too rapid an ascent or inability to acclimatize leads to high altitude illnesses. These include the mild form of acute mountain sickness (AMS), or the potentially fatal high altitude pulmonary edema (HAPE) or high altitude cerebral edema (HACE).
Who Can Get Altitude Sickness?
Anyone who goes to high altitude can get Acute Mountain Sickness. It is primarily related to individual genetics and how fast you go up. There is no difference in age, gender, physical fitness, or previous visits. An uneventful trip to altitude does not guarantee you won't have a serious problem on the next visit to that exact same altitude. There is no way to predict who is likely to get sick at high altitudes.
What are the Usual Symptoms?
AMS - Most people will experience shortness of breath with exercise levels that would not affect them at lower altitudes. Same for a mild headache, decreased appetite, and uneasy sleep. These can be expected and will decrease in severity as the body adjusts to the lower oxygen levels.
HAPE - a Severe cough and shortness of breath even at rest. May cough blood.
HAPE - Severe unremitting headache. Confusion. Vertigo. Unconsciousness.
What is the Treatment?
AMS - Diamox, if taken in preparation for high altitude travel, may lessen symptoms. Check with your medical travel consultant. On arrival - go slow at first. Rest and hydration will help lessen symptoms but only time will acclimatize you to this new height. In the meantime, eat lightly, avoid alcohol and caffeine which can dehydrate.
HAPE and HACE - Administer emergency oxygen while transporting the victim to lower altitude ASAP. No other treatment is effective.
Can You Acclaimatize?
With time the body can adapt to the decrease in oxygen at a specific altitude. This process is known as acclimatization and generally takes one to three days at any given altitude, e.g. If you go from sea level to 5,000 feet and spend several days at that altitude, your body will acclimatize to 5,000 feet. If you then climb to 10,000 feet your body has to acclimatize once again.
Protect Your Eyes
01. UVA Radiation
Overexposure to UVA radiation can lead to the development of cataracts and macular degeneration.
02. UVB Radiation
Thought to potentiate the production of pingueculae and pterygia. These are growths on the eye's surface can become unsightly and cause corneal problems as well as distorted vision. UVB rays also can cause snow blindness which causes temporary vision loss usually lasting 24-48 hours.
03. High-energy visible (HEV) Light
High-frequency light indicated as a cause of age-related macular degeneration.
04. UV levels are much higher
In the tropics
At high altitude.
Near snow, water, or sand
Cloud-cover is not protective as UV rays easily penetrate clouds.
05. Choosing Sunglasses
UV Blocking: Look for sunglasses that block 100 percent of UV rays and absorb HEV rays. This information should be printed on the hangtag or price sticker of any sunglasses you buy. If it isn't, find a different pair.
Polarized lenses substantially reduce glare. But in some instances, polarized lenses react with the tints in windshields, creating blind spots. They can also diminish the visibility of LCD readouts on cameras and iPads. If this occurs, consider mirrored lenses as a glare-reducing alternative.
Lens Color: The amount of UV protection sunglasses provide is unrelated to the color and darkness of the lenses. A light amber-colored lens can provide the same UV protection as a dark gray lens. But for HEV protection, color does matter. Most sunglass lenses that block a significant amount of blue light will be bronze, copper or reddish-brown (see Lens Tint Guide ). Alert - Dark glasses without UV protection are worse than none. The tinted lens will dilate your pupil allowing even more radiation onto the retina than without the glasses.