Aspen's Altitude Sickness: Is Your Smartwatch Lying?

By Franklin Everett Shaw

March 2, 2026

Are you trusting your smartwatch to tell you if you’re getting altitude sickness in Aspen? You might be making a dangerous mistake. While these devices are increasingly popular, relying solely on their SpO2 readings at 8,000 feet can be misleading and potentially harmful.

Smartwatches are convenient, but they’re not medical-grade devices. Their accuracy, already questionable at sea level, plummets in high-altitude environments like Aspen, Colorado.

The thin air at 8,000 feet presents a significant challenge. Lower oxygen partial pressure means less oxygen is available to bind to hemoglobin in your blood.

This physiological change is what pulse oximeters, including those in smartwatches, attempt to measure. However, the technology isn’t perfect, and several factors unique to high altitude exacerbate its limitations.

One major issue is peripheral vasoconstriction. At altitude, your body prioritizes oxygen delivery to vital organs, constricting blood vessels in your extremities, like your wrists.

This reduced blood flow makes it harder for the smartwatch sensor to accurately detect the oxygen saturation in your blood. The sensor relies on light absorption through the skin, and less blood means a weaker signal.

Furthermore, cold temperatures, common in Aspen, worsen vasoconstriction. Imagine skiing on a brisk day; your smartwatch reading will likely be even less reliable.

Skin pigmentation also plays a role. Melanin absorbs light, potentially interfering with the sensor’s ability to accurately measure oxygen saturation.

Motion artifact is another significant problem. Even slight movements can disrupt the sensor’s readings, leading to inaccurate results. This is especially problematic if you’re active, hiking, or skiing.

So, what does this mean for you, the Aspen visitor? Don’t blindly trust your smartwatch.

A reading that seems normal might be falsely reassuring, masking early signs of altitude sickness. Conversely, a low reading might cause unnecessary panic.

Here’s a practical approach to monitoring your oxygen saturation in Aspen:

1. Establish a Baseline: Before your trip, take several SpO2 readings with your smartwatch at sea level. Note the average reading and any variations. This gives you a reference point.

2. Compare with a Clinical Pulse Oximeter: Consider purchasing a clinical-grade pulse oximeter. These devices are more accurate and reliable than smartwatches. Compare your smartwatch readings with the clinical oximeter at sea level and at altitude. This will help you understand the smartwatch’s accuracy in different environments.

3. Take Readings at Rest: Ensure you are sitting still and relaxed for at least five minutes before taking a reading. Avoid taking readings immediately after exercise or exposure to cold.

4. Warm Your Hands: If your hands are cold, warm them up before taking a reading. This will improve blood flow to your wrist.

5. Consider Skin Pigmentation: Be aware that skin pigmentation can affect the accuracy of the reading. If you have darker skin, the smartwatch might underestimate your oxygen saturation.

6. Look for Trends, Not Just Single Readings: Don’t rely on a single reading. Take multiple readings over time and look for trends. A consistently decreasing SpO2 level is more concerning than a single low reading.

7. Recognize the Symptoms of Altitude Sickness: Don’t rely solely on SpO2 readings. Be aware of the symptoms of altitude sickness, such as headache, nausea, fatigue, and shortness of breath.

8. Hydrate Adequately: Dehydration can worsen altitude sickness. Drink plenty of fluids.

9. Avoid Alcohol and Sedatives: These substances can suppress breathing and worsen altitude sickness.

10. Ascend Gradually: Give your body time to acclimatize to the altitude. Avoid strenuous activity during your first few days in Aspen.

11. Seek Medical Advice: If you experience symptoms of altitude sickness, seek medical advice immediately. Don’t rely solely on your smartwatch to determine your health status.

Here’s a specific scenario: Imagine you’re hiking the Smuggler Mountain Trail in Aspen. Your smartwatch shows an SpO2 of 92%. You feel slightly fatigued, but you attribute it to the exertion. However, you also have a mild headache.

Don’t dismiss the headache. The 92% reading might be falsely reassuring. Stop hiking, rest, and monitor your symptoms. If your headache worsens or you develop other symptoms, descend to a lower altitude and seek medical attention.

A common mistake is assuming that a smartwatch reading within the “normal” range (typically 95-100%) means you’re fine. At 8,000 feet, a “normal” SpO2 is lower than at sea level.

A reading of 92% might be acceptable for some individuals at that altitude, but it could also indicate early signs of altitude sickness in others. Individual responses to altitude vary.

Another pitfall is relying on the smartwatch’s “altitude acclimatization” feature, if it has one. These features are often based on algorithms that are not validated by scientific research.

They might provide a false sense of security. Always prioritize your symptoms and consult with a healthcare professional if you have concerns.

Remember, smartwatches are consumer devices, not medical instruments. They can provide some information about your oxygen saturation, but they should not be used as a substitute for professional medical advice.

In Aspen, where the altitude poses a real risk, it’s crucial to be informed and proactive about your health. Don’t let a potentially inaccurate smartwatch reading lull you into a false sense of security.

Prioritize your well-being, listen to your body, and seek professional medical advice when needed. Your health is worth more than relying on a gadget.