High altitude is typically considered to begin at 8,000 feet although you may feel some effects at lower elevations. It is normal to feel increased effort level with your normal or even slower paces at altitude. Minor symptoms such as fatigue or headache are common and may indicate Acute Mountain Sickness (AMS) which is not dangerous but warrants monitoring for additional symptoms or progression of symptoms. Most of the dangerous complications of altitude occur at over 10-12,000 feet. Exertion increases your risk for altitude sickness so if you are racing at altitude, regardless of acclimatization you are at risk. YOU ARE AT INCREASED RISK WITHOUT ACCLIMATIZATION. Other factors such as genetics, prior altitude illness or how quickly you ascend also play a role.

High Altitude Pulmonary Edema (HAPE)

HAPE is where you develop fluid in your lungs from altitude and is a medical emergency.

Do you feel short of breath at rest?
If so consider descending and if symptoms do not improve seek medical care

Do you have a cough and shortness of breath?
If yes consider the severity of your symptoms. If you are coughing up pink tinged or white phlegm or feel substantially short or breath you are at risk for High Altitude Pulmonary Edema (HAPE) and should descend  NOTE: Exertion free descent is important with suspicion of HAPE so do not push hard to descend.

What color is the skin?
If you see a purplish discoloration, especially notable around the lips you should descend and recheck. This suggests your oxygen level is too low.

High Altitude Cerebral Edema (HACE)

HACE is where you develop swelling in your brain from altitude and is a medical emergency

Do you have a headache?
Isolated headache does not indicate HACE but monitor closely for other symptoms.

Do you have confusion?
Confusion is very concerning and should prompt descent and medical attention.

Do you have poor coordination or ataxia (unsteadiness)?
This is also concerning and should prompt descent and medical attention.

In additional to descent, supplemental oxygen, dexamethasone (a prescription steroid) and acetazolamide can be part of treatment. Of note these medications are on the WADA banned list so should not be taken as preventative treatment in a sanctioned race.