Camping at altitude: acclimatization, sleep and gear

What changes when you camp high in the mountains: how acclimatization works, sensible ascent pacing, recognizing altitude illness early, and how cold nights, stoves and sun differ up high.

By the CampTier team · Updated 2026-10-15 · About 5 min read

Illustrative photo of a tent pitched in an alpine landscape — Illustrative stock photo, not a product photo. Photo: U.S. Forest Service- Pacific Northwest Region (Public domain).

Why altitude feels different

Air pressure drops as you climb, so each breath delivers less oxygen even though the air is still about 21 percent oxygen. Your body adapts by breathing faster and deeper, raising heart rate and, over days and weeks, changing blood chemistry. That adaptation is acclimatization, and it takes time. Many people notice the effects starting somewhere around 2,500 meters (about 8,000 feet), and some notice changes lower than that. A campground at a high trailhead can be the first night many visitors spend at altitude, often after a flight and a long drive from near sea level. This guide is general information; if you have heart or lung conditions, are pregnant, or have had altitude illness before, talk to a clinician before a high trip.

Pacing the ascent

The most reliable way to reduce altitude illness is to go up gradually. Common mountain guidance includes:

If you can, spend a night at a moderate elevation before sleeping high, for example in a town partway up.
Above about 3,000 meters (roughly 10,000 feet), avoid raising your sleeping elevation by more than a few hundred meters (often cited as 300 to 500 meters, about 1,000 to 1,600 feet) per night.
Build in a rest day every few days of gain.
"Climb high, sleep low" works: day hikes above camp are fine if you return to sleep lower.

Car campers can still use these ideas. Driving straight from sea level to a campground at 3,000 meters and doing a big hike the same afternoon is a common recipe for a rough night.

Recognizing altitude illness

Acute mountain sickness (AMS) usually shows up within 6 to 24 hours of arriving at a new elevation. It feels like a hangover: headache plus one or more of nausea, loss of appetite, fatigue, dizziness or poor sleep. Mild AMS often improves with rest, fluids and not going higher until symptoms resolve.

Two serious forms need urgent action:

HACE (high-altitude cerebral edema): confusion, unusual drowsiness, loss of coordination (stumbling, unable to walk heel to toe in a straight line), severe headache.
HAPE (high-altitude pulmonary edema): breathlessness at rest, a persistent cough, sometimes with frothy or pink sputum, crackling breathing, extreme fatigue, tight chest.

The key treatment for serious altitude illness is descent, even a few hundred meters, and medical help. Never leave someone with these signs alone, and never let them descend alone. A simple rule many groups use: never go higher with symptoms, and go down if they get worse.

Some travelers use prescription medication to help prevent altitude illness. That is a conversation to have with a clinician well before the trip, not something to improvise at camp.

Sleep at altitude

Broken sleep is common for the first nights up high. Some people notice periodic breathing, where breaths speed up, slow, pause briefly and restart. It can be unsettling for tent-mates but is common at altitude. Helpful habits:

Keep the first evening low-key; skip the big hike on arrival day.
Avoid alcohol and sleeping pills on early nights, since they can depress breathing.
Stay warm enough to sleep (cold makes everything worse).
Prop your head slightly with a pillow or stuff sack of clothes.

Cold, wind and gear

Temperature typically drops with elevation, and clear high-altitude nights lose heat fast. Even in summer, nights near or below freezing are common at high campsites. Check:

Sleeping bag ratings with honest margin, see sleeping bag temperature ratings.
Pad insulation, because cold ground drains heat, see sleeping pad R-values.
A tent that handles wind, with full guying; see tent season ratings and pitching a tent in wind.
Warm layers you can wear to bed and to breakfast, see layering for camping.

Stoves and cooking

Water boils at a lower temperature up high, so food takes longer to rehydrate and cook, and you will use more fuel. Pasta and rice may need extra soaking time. Canister stoves can struggle in cold temperatures because the fuel vaporizes poorly; keeping the canister warm in a jacket before cooking helps, and some stoves and fuel blends are designed for colder conditions. Never bring a stove inside the tent: carbon monoxide risk rises in enclosed spaces, and altitude makes its effects harder to notice. More in camp stoves and fuel.

Sun and dryness

UV exposure increases with elevation and reflects off snow, rock and water. Sunburn and snow blindness happen quickly at altitude even on cool days. Pack high-SPF sunscreen, lip balm with SPF, a brimmed hat and sunglasses with good UV protection; see sun protection for campers. The air is also dry, so you lose more water through breathing.

Checklist for a high camp

Plan a gradual sleeping-elevation gain and a rest day.
Know the AMS, HACE and HAPE signs, and agree as a group to descend if needed.
Pack a bag and pad rated for colder nights than the valley forecast.
Bring extra fuel and allow longer cooking times.
Pack strong sun protection and extra water.

Hydration and eating up high

Drinking enough matters at altitude because dry air and heavy breathing increase water loss, but over-drinking does not prevent altitude illness. Aim for steady intake and pale urine. Appetite often drops at altitude; carbohydrate-rich, easy-to-eat food such as oatmeal, noodles, crackers and dried fruit tends to go down better than heavy meals. Eat small amounts often. See how much water to carry for planning by leg.

Weather moves fast in the mountains

Afternoon thunderstorms are common in many mountain ranges in summer. Plan exposed ridges and summits for the morning and be heading down by early afternoon. Lightning guidance is in thunderstorm and lightning safety. Weather can turn from sunny to sleet in an hour, so pack rain gear and warm layers even when the trailhead is hot.

Children and dogs

Children can get altitude illness too and may have trouble describing it; watch for fussiness, poor appetite, unusual sleepiness or vomiting after arriving high. Plan the same gradual approach and be ready to descend. Dogs also feel the effects of exertion at elevation; keep their pace easy, offer water often and watch for unusual lethargy.

Coming down

Most mild altitude symptoms ease within a day or so of descending. If someone was seriously ill up high, get them checked by a medical professional even if they feel better after descent.

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General guidance from CampTier, based on manufacturer instructions and common outdoor practice. We don’t claim hands-on testing. Always follow your gear maker’s care and safety instructions. See our safety notes.