©istockphoto/swissmediavisionWill your adven­tures be tak­ing you into high-alti­tude envi­ron­ments this sum­mer? If so, be careful—and do your research. Alti­tude affects every­body dif­fer­ent­ly, and it’s impor­tant to under­stand what you’re get­ting into.

It’s Called “Atmos­pher­ic Pressure”
The first step? Stop say­ing that the air is thinner—because tech­ni­cal­ly, the air itself isn’t chang­ing as you climb high­er. The tro­pos­phere (which stretch­es from sea lev­el to rough­ly 65,000 feet) always con­tains 20% oxy­gen and near­ly 80% nitro­gen. What does change is the atmos­pher­ic pres­sure, which decreas­es as you ascend? At the sum­mit of Mount Ever­est, for exam­ple, the atmos­pher­ic pres­sure is less than 30% of the pres­sure at sea level.

You don’t need to go to the sum­mit of Mount Ever­est to feel changes in your body, though. Accord­ing to the med­ical def­i­n­i­tion, any­thing above 8,000 feet (or 2,440 meters) is con­sid­ered high alti­tude. It’s rare to have seri­ous issues below 12,000 feet, but it’s dif­fer­ent for every per­son every time. That’s one of the inter­est­ing things about alti­tude sick­ness: it can hap­pen to any­body, regard­less of age, phys­i­cal con­di­tion­ing, expe­ri­ence, or gen­der. All bod­ies are unique, and you’ll be most in tune with yours if you’re hon­est with your­self about what you feel.

Alti­tude Sickness
That said, most peo­ple will expe­ri­ence at least some symp­toms when trav­el­ing above 12,000 feet. Acute Moun­tain Sick­ness, or AMS, is the catch-all med­ical term for feel­ing shit­ty up high—and experts say it feels exact­ly like a right­eous hang­over. Symp­toms include dif­fi­cul­ty sleep­ing, fatigue, a mild to mod­er­ate headache, loss of appetite, nau­sea, an ele­vat­ed heart rate, and short­ness of breath. None of these symp­toms are life-threat­en­ing, but they are your body’s way of giv­ing you infor­ma­tion. Slow down, stay hydrat­ed, eat well, and rest as much as pos­si­ble. Take ibupro­fen or aceta­minophen. For most climbers, AMS is man­age­able and will resolve with prop­er acclimatization.

For some peo­ple, though, it gets worse. There are two pri­ma­ry con­cerns at alti­tude: HACE and HAPE. HACE, or high alti­tude cere­bral ede­ma, is a build-up of flu­id around the brain. Symp­toms include a per­sis­tent headache, atax­ia, and altered lev­el of con­scious­ness. HAPE, or high alti­tude pul­monary ede­ma, is a build-up of flu­id around the lungs. Symp­toms include a per­sis­tent cough, short­ness of breath, and pink phlegm. Both are every bit as seri­ous as they sound, and both dic­tate an imme­di­ate descent and med­ical attention.

How can you pre­vent alti­tude sick­ness? Don’t rush. Sched­ul­ing lots of time to accli­ma­tize are the best way to pre­vent issues. Be gen­tle with your body, and when in doubt, descend.

For more infor­ma­tion about how to stay safe in the moun­tains, check out Wilder­ness Med­i­cine by William W. Forgery, MD, and Alti­tude Ill­ness: Pre­ven­tion & Treat­ment by Stephen Bezruchka.