How to prevent and treat altitude sickness
The views from the heights of the mountainous regions can be magical and spectacular, but not when you bend over, huff and puff, feel nauseous and have a headache. Altitude sickness, often referred to as acute altitude sickness, can occur as low as 5,000 feet and gets worse the closer you get to 10,000 feet. It can also take many forms: only some are serious, but all can put a damper on your adventures.
If you’re on your way to the top, here’s how to prepare for and treat symptoms, and what to look out for to ensure you stay happy and healthy as you get closer to heaven.
Causes of Altitude Sickness
Contrary to popular belief, altitude sickness does not occur because there is less oxygen the higher you go.
“You’re still breathing 21 percent oxygen, it’s just more distributed,” explains Graham Prather, education manager at the National Outdoors Leadership School (NOLS) and responsible for wilderness medicine courses.
[Related: Tips for picking the best hiking trail]
It’s not the composition that counts, it’s the concentration. At high altitudes, there is less atmospheric pressure, which reduces the number of oxygen molecules in a given volume of air compared to the same volume at lower altitudes. At 10,000 feet, for example, you get only 69 percent of the oxygen that you would get at sea level.
The higher you go, the less efficient your breathing becomes, resulting in less and less oxygen with each inhale. In response, your body tries to get the oxygen it needs, so you start breathing faster. But despite all that exertion, there’s still less oxygen getting into your blood and muscles, which is why physical activity at higher altitudes feels so much harder. This condition is called hypoxia and causes the symptoms of altitude sickness.
What are the symptoms of altitude sickness?
Altitude sickness is no fun and definitely not easy to ignore. Symptoms are likely to include a headache, nausea, possibly vomiting, and possibly even loss of appetite. At times it can also be accompanied by the extremely aggravating combination of fatigue and insomnia.
“It felt like a really bad hangover,” Prather says of the first time he experienced altitude sickness.
It’s a feeling that usually sets in within a day or two of arriving at a high altitude destination, but before that you may experience mild symptoms such as light-headedness, especially when bending over and getting up quickly or climbing stairs.
In addition, high altitudes also make you more prone to dehydration, which can worsen symptoms of altitude sickness. That’s partly because you’re expelling moisture with every exhale, so an increased breathing rate causes your body to lose more water than usual. And the dry conditions that come with higher elevations don’t help: the lack of moisture means moisture evaporates quickly, which can fool you into thinking you’re not sweating as much as you are and don’t need to rehydrate. It is important to drink plenty of water, especially during the first few days of settling in.
“We can’t drink away the altitude sickness, but at least we can’t get dehydrated,” says Prather.
Most of the time, these symptoms are not life-threatening and only require acclimatization to subside. But especially at altitudes above 10,000 feet, symptoms can worsen and lead to more serious health conditions: high-altitude cerebral edema (HACE) or high-altitude pulmonary edema (HAPE).
HACE is typically associated with loss of balance, episodes of confusion, and possibly a severe headache. On the other hand, HAPE presents with decreased stamina, breathlessness (even at rest), and a persistent cough that sounds dry at first and turns into wet, indicating the presence of fluid in the lungs. HAPE is more common than HACE, but both can be deadly, making it important to go to altitude as soon as symptoms appear.
Who is at risk of altitude sickness?
Unfortunately, science hasn’t identified any specific markers for who might or might not suffer from altitude sickness. The only indicator seems to be that if you’ve suffered from symptoms before, you might experience them again. But at the same time, just because you’ve never experienced symptoms doesn’t necessarily mean you never will.
Not even athletes or people in excellent shape are immune. In fact, Prather says, these are the ones he worries about the most when leading trips, as non-athletes tend to listen to their bodies and pay attention to symptoms, while athletes may try to manage the pain or discomfort overcome.
How to prevent altitude sickness
There are three main factors that affect not only your risk of altitude sickness, but also the amount of hypoxic stress you put on your body — altitude, how fast you ascend, and how hard you exert yourself. Luckily, you can prepare for any of them.
Start planning ahead and allow enough time for acclimatization. Don’t expect to land in Quito, Ecuador (9,350 feet above sea level), the Himalayas (29,032 feet), or even Denver (5,279 feet) and set off immediately to scale a moderate peak yourself. Your body takes between 24 and 48 hours to adjust to new altitudes, but the time it takes you to fully acclimate can vary. The National Outdoor Leadership School curriculum states that “when traveling rapidly to 10,000 feet or higher, take two to three days of rest with light exercise.” If you take the time to acclimatize, the symptoms probably won’t hit as hard.
Once you’ve given your body time to adjust to the new conditions, don’t rush things – the faster you climb, the more likely you are to experience symptoms. If you have a multi-day trek to higher elevations ahead of you, Prather recommends breaking the trip up into multiple days so that once you’re past 10,000 feet, you and your team can ascend in stages where sleeping at altitude every night doesn’t more than 1,500 feet higher than the night before. Include frequent rest days as well.
If you can, consider spending the night at lower elevations, as sleeping at high altitude is even harder on your body. You can do climbing tours during the day and descend to your base camp at night.
Before, during, or even after a high-altitude hike, avoid alcohol (especially when you first arrive and your body is not yet acclimatized) and sedatives to help you sleep, as they can worsen symptoms. Both substances, Prather explains, suppress your respiratory drive by slowing your breathing and making each breath shallower than usual, which is the opposite of what you need at high altitude.
“You want your respiratory drive to respond to the atmosphere you’re in,” he says.
How do you treat altitude sickness?
Altitude sickness can be insidious. So even if you’ve tried your best to prevent it, you can still have symptoms. When it comes to feeling better, light exercise can help, so take a light walk to get your breathing rate up. Since nausea is one of the most common symptoms, it’s possible that you don’t feel like eating, but you should also take care to maintain an adequate diet to stay in good health.
Over-the-counter pain relievers like ibuprofen and acetaminophen can help reduce the severity of headaches, but avoid stronger ones like opiates, which have similar effects to alcohol and tranquilizers, Prather says.
[Related: Does training at high altitudes help Olympians win?]
If you expect altitude sickness, ask your doctor about acetazolamide. This drug can relieve symptoms of altitude sickness by speeding up your respiratory drive. It works by making your blood pH more acidic, which leads your body to think there is too much carbon dioxide. As a result, your system makes your breathing faster and deeper to eliminate carbon dioxide, resulting in a higher concentration of oxygen.
Finally, if altitude sickness persists or worsens despite your best prevention and treatment efforts, take Prather’s words as your new motto: “Don’t go up until your symptoms subside.” If there is no improvement, it may be time to move down to a lower altitude. Don’t worry – you can always try again next time.