Should you bring a pulse oximeter to Everest Base Camp? What the number really means
A fingertip oximeter is cheap and many trekkers carry one. What your oxygen reading can and cannot tell you at altitude, and why symptoms matter more.
Prakash Tamang 4 min read
A fingertip pulse oximeter costs little and weighs almost nothing, and many trekkers now carry one to Everest Base Camp. It is worth having, but only if you know what it cannot tell you. The number it shows, your blood oxygen saturation, falls as you climb for everyone, including people who feel perfectly well. Doctors diagnose altitude sickness from symptoms, not from that number, and a 2024 review of the research found no compelling evidence that the reading on its own predicts who will get sick.
I earn a small commission if you buy through the Amazon links on this page. It costs you nothing, and anything you are better off renting in Thamel is marked as a rental, with no link.
- Your oxygen reading drops as you climb, and a low number alone does not mean you are ill.
- Acute mountain sickness is diagnosed from symptoms, headache, nausea, dizziness, fatigue, not from the oximeter.
- It is most useful for trends over several days and as extra information for your guide.
- If you feel worse, tell your guide and do not go higher, whatever the number says.
What the number is
The percentage of your blood’s haemoglobin carrying oxygen. At sea level it is usually in the high 90s. As you climb, the air holds less oxygen and the number falls, a lot, for healthy people too. It also moves with how you are sitting, how cold your fingers are and whether you have just walked in from the cold. Cold fingers are the most common reason for a strange reading.
What it cannot tell you
Whether you have altitude sickness. The Wilderness Medical Society’s guidelines treat acute mountain sickness as a clinical diagnosis based on symptoms, assessed with the Lake Louise score. A 2024 systematic review in Experimental Physiology found no compelling evidence that a single oxygen reading independently predicts who will develop it. Two people with the same number can feel completely different.
How to use one well
Same time, same way, every day, and read the trend. Take the reading at rest, sitting down, with a warm finger, at the same time each evening. A reading that keeps falling while you also feel worse is worth telling your guide about. A low number while you feel fine, on an acclimatisation day, is usually just altitude.
| What you see | What it usually means | What to do |
|---|---|---|
| Low number, feel fine | Normal response to altitude | Keep to the itinerary, keep drinking |
| Falling number, new headache | Possible early altitude sickness | Tell your guide, do not go higher |
| Worse symptoms at rest | Serious, whatever the number | Descend with your guide |
| Odd reading, cold fingers | Measurement error | Warm your hands and retake it |
Headache, nausea, dizziness, unusual tiredness, breathlessness at rest or confusion mean you tell your guide straight away and do not go higher. Do not let a reassuring number talk you out of it. This is general information, not medical advice; talk to a doctor before you travel.
Our Everest Base Camp trek includes acclimatisation days at Namche and Dingboche, and your guide carries a pulse oximeter and an altitude kit: from US$1,850 solo.
See the Everest Base Camp trekShould I bring a pulse oximeter to Everest Base Camp?
It is cheap and light and can be useful for tracking trends, as long as you understand that symptoms, not the reading, decide whether you are ill.
What oxygen level is normal at Everest Base Camp?
Readings fall well below sea-level values for everyone at that altitude, and vary widely between healthy people. Compare your own readings over several days rather than against a single figure.
Can a pulse oximeter detect altitude sickness?
No. Acute mountain sickness is diagnosed from symptoms. Research has found no compelling evidence that an oxygen reading on its own predicts it.
Why is my oximeter reading low when I feel fine?
Oxygen saturation drops at altitude for everyone. Cold fingers and movement can also lower the reading. Warm your hand and retake it at rest.
Keep reading
What to pack for the trail.
The full checklist.
Batteries, screens and cold.
Why a guide matters up high.
The verdict: bring one, read it every evening, and believe your symptoms over the number every time.
Sources: Luks et al., Wilderness Medical Society Clinical Practice Guidelines for the Prevention, Diagnosis, and Treatment of Acute Altitude Illness, 2024 update (Wilderness & Environmental Medicine); Goves et al., “Pulse oximetry for the prediction of acute mountain sickness: a systematic review”, Experimental Physiology, 2024.
As an Amazon Associate we earn from qualifying purchases, at no extra cost to you.
Written by
Prakash TamangPokhara-based, NMA-certified trekking guides. We’ve led 5,000+ treks across the Annapurna and Everest regions since 1998 — every word here comes from the trail. More from this author →
Ready to Trek?
From reading about it to standing on it
Our Pokhara-based guides have been doing this since 1998. Tell us your dates and fitness level — we'll build your perfect itinerary. Free, no obligation.
More guides like this
Popular trips to consider
View all treks & toursFree Trekker’s Insider Guide
Permits, packing lists, cost breakdowns — no fluff.
We send one useful email. You can unsubscribe anytime.