How to Prepare and Pack for a High-Altitude Hike

There are few experiences better than summiting your first fourteener—the crisp mountain air, the feeling of being above it all, and the inevitable (and hopefully minor) mishaps that will be recounted at dinner tables and around campfires for years to come. But to keep the ending happy, you need to do your research first to prevent a miserable trip or even injury. Here’s what you should consider before attempting your first high-altitude hike.

The Risks

Three things usually get people into trouble: the altitude, spotty communication, and heightened sun exposure. Even if you live at high elevation, hiking up to 14,000 feet is no cakewalk, and the risk is even greater if you’re coming from sea level. Your body will need time to adjust so you don’t get altitude sickness (more on that below). And you’ll most likely be out of cell-service range on your hike, so if something happens on the mountain, you’ll have to figure out a way to contact help. It’s a good idea to travel with a group, but at least let several friends and family members know where you’re headed, your route, and how long you plan to be out. Lastly, since you’ll be closer to the sun, prepare your skin for extra exposure with proper clothing and sunscreen, and don’t forget to protect your eyes with UV-blocking sunglasses.

How to Acclimate Properly

The higher you go, the thinner the air gets as oxygen levels decrease, which means there's less oxygen flowing through your blood to your organs and muscles. This can result in headaches, nausea, shortness of breath, and an inability to exercise like normal. According to a 1999 Princeton University study, 75 percent of people will have mild symptoms of altitude sickness at elevations over 10,000 feet. In the same study, researchers found that symptoms usually start between 12 to 24 hours after arrival at altitude and begin to decrease in severity by about the third day. It’s important to note that no matter how much you prepare, you can still fall ill with altitude sickness—being physically fit does not make you immune.

If you experience any of the symptoms, descend to camp or hang out at a lower altitude until your body is better able to acclimate. If you choose to ignore the symptoms and climb higher, you could experience some more acute—and potentially fatal—forms of altitude sickness like pulmonary edema (fluid in the lungs) or cerebral edema (fluid in the brain). While these cases are rare, listen to your gut and head down if something starts to feel off. The mountain isn’t going anywhere.

The Right Way to Pack

Weather conditions can change in a heartbeat at high altitude, and mountains can sometimes see all four seasons in a single day. Here’s what you should bring for a day hike at elevation.

Clothing

• Merino-wool or synthetic base layers: A good base-layer set will help pull moisture away from your body so you’ll stay warm longer. Those made of wool or synthetics will wick faster than cotton or other materials. 
• Hiking pants or leggings: Most hiking pants are designed with a layer of DWR to help repel light rain and snow and targeted gussets to help with your range of motion.
• Lightweight, compressible rainpants: If it really starts to pour, bust out a pair of lightweight rainpants. They won’t take up much room in your pack but will save you in an afternoon storm, and most slip over existing pants.
• A lightweight, compressible Gore-Tex rainjacket: Other than protecting you from the rain, a jacket with Gore-Tex will breathe better than a laminate rainjacket and will prevent you from overheating.
• A quick-drying hiking shirt: If you do get wet from sweat or rain, a synthetic shirt will vent moisture so you don’t hike around in a wet top all day.
• Liner gloves: These are lightweight, won’t take up much room in your pack, and are easy to throw on for extra warmth. 
• A warm beanie: Since you lose the most heat through your head, a beanie is a must if there’s a chance the mercury could drop.
• A Buff: This lightweight fabric tube can be used as a hat, a balaclava, a headband, or even a hair tie. 
• Lightweight down jacket: If it gets really cold, layer a puffy under your Gore-Tex rainjacket to hold in heat.

Footwear

• Hiking boots or trail runners: You’ll need a pair of well-broken-in shoes to be comfortable for miles. Some people like wearing trail runners because they’re more lightweight and often have more cushioning. But some folks prefer the stability and support provided by a traditional pair of hiking boots. The best choice is what works for you.
• Wool socks: Wool adjusts rapidly to your body temperature and dries quickly. We recommend taking two pairs with you in case your feet get wet and you need to change. 
• A pair of waterproof gaiters: When the trail turns muddy or snowy, these will keep the elements out of your boots.

Gear

• A backpack in the 20-to-40-liter range: Having a pack with at least 20 liters of capacity to hold all your gear is safe. But if you’ll be out a long time, size up. If you prefer carrying trekking poles, look for a pack with external carrying loops.
• A waterproof pack cover: If it starts raining or snowing, this will protect the contents of your pack and weighs next to nothing.
• Trekking poles: Some might consider these optional, but trekking poles will help save your knees on a descent. Some trekking poles fold down incredibly small and will easily fit inside your pack or can be strapped to the outside.
• A first-aid kit properly sized for your group: It is incredibly easy to build your own first-aid kit, but buying one will ensure everything you need is there. 
• A headlamp: You might be hiking in the early morning or at night, so you’ll want to have a reliable light source. And be sure to bring extra batteries.
• Sunglasses: Light reflects off of snow, and it’s easy to damage your eyes at altitude. Invest in a pair that blocks 100 percent of harmful UV rays—most sunglasses available these days will, but double-check for safety.
• A two-liter hydration reservoir: You could use water bottles, but they’re unwieldy and take up valuable pack space. We prefer hydration reservoirs because they hold a large quantity.
• Sunscreen and SPF lip balm: Higher altitudes expose you to stronger sun, so even if it’s cold, you still need to apply sunscreen. And don’t forget about your lips.
• A GPS communicator: You’ll most likely be out of cell-phone range, so it’s a good measure to have a GPS communicator on you to call for help.
• A map and a compass: Paper maps still have a time and place. Know where you’re going, and learn how to orient yourself just in case.

Food and Water

• Several high-calorie food bars: These are great for afternoon snacks or even meal replacements. More calories equal more energy for summiting and descending.
• Water-purification tablets or a small water filter: If you run out of water, you’ll need a way of getting more. Tablets are quick to use, but a water filter will provide a larger quantity of water.
• Water: To mitigate your chances of altitude sickness, you should drink at least three to four quarts per day, and your urine output should be copious and clear.