Denver's Smartwatch Secret: Altitude's Hidden Health Risk

By Franklin Everett Shaw

May 17, 2026

Ever felt like you’re breathing through a straw after landing in Denver? It’s not just the thin air; it’s the altitude, and it can hit you hard. But what if you could get ahead of the curve, using technology you already own?

Denver, the Mile High City, sits at 5,280 feet above sea level. That’s a significant change for anyone coming from lower elevations. Altitude sickness, or acute mountain sickness (AMS), is a real concern, and ignoring it can ruin your trip or even lead to serious health problems.

Smartwatches, once just fancy timekeepers, are now packed with sensors that can provide valuable insights into your health. One of the most useful for altitude acclimatization is the blood oxygen saturation (SpO2) sensor. This measures the percentage of oxygen in your blood, a key indicator of how well your body is adapting to the lower oxygen levels at higher altitudes.

Not all smartwatches are created equal when it comes to SpO2 accuracy. For reliable readings in Denver, consider models like the Apple Watch Series 9, the Garmin Fenix 7, or the Fitbit Sense 2. These devices have been shown to provide relatively consistent and accurate SpO2 measurements, especially when worn correctly.

So, how do you actually use this data to manage altitude sickness in Denver? It’s a three-step process: monitor, interpret, and adjust.

First, monitor your SpO2 levels regularly, especially during your first 24-48 hours in Denver. Take readings at rest, ideally in the morning and evening, and after any physical activity. Consistency is key.

Next, interpret your readings. A normal SpO2 level at sea level is typically between 95% and 100%. In Denver, expect this to be lower. A reading between 90% and 95% is generally considered acceptable for acclimatized individuals. However, if your SpO2 consistently drops below 90%, or if you experience symptoms like headache, nausea, dizziness, or shortness of breath, it’s a sign that you’re not acclimatizing well.

Finally, adjust your behavior based on your SpO2 levels and symptoms. This is where the real power lies. If your SpO2 is lower than expected, or if you’re experiencing symptoms, take these steps:

• Hydrate aggressively: Denver’s dry air exacerbates dehydration, which can worsen altitude sickness. Aim for at least a gallon of water per day. Consider adding electrolytes to your water to help your body retain fluids.
• Reduce your activity level: Avoid strenuous exercise during your first few days. Take it easy and allow your body to adjust. Opt for gentle walks instead of intense hikes.
• Consider supplementation: Some people find that taking acetazolamide (Diamox), a prescription medication, can help with acclimatization. Consult with your doctor before taking any medication. Over-the-counter options like ibuprofen can help manage headaches.
• Increase your iron intake: Low iron levels can hinder oxygen transport. Consider incorporating iron-rich foods into your diet or taking an iron supplement (after consulting with a doctor).
• Avoid alcohol and caffeine: These substances can dehydrate you and interfere with sleep, both of which can worsen altitude sickness.

Let’s say you’re visiting Denver from Chicago. You arrive and immediately go for a hike in Red Rocks Amphitheatre. Later that evening, you check your SpO2 and it’s at 88%, and you have a throbbing headache. This is a clear indication that you’re experiencing altitude sickness. You should immediately stop any strenuous activity, hydrate aggressively, and consider taking ibuprofen for the headache. If your symptoms worsen or your SpO2 drops further, seek medical attention.

One common mistake is ignoring the symptoms of altitude sickness and pushing through. This can be dangerous and lead to more serious complications like high-altitude pulmonary edema (HAPE) or high-altitude cerebral edema (HACE). Listen to your body and don’t be afraid to take it easy.

Another pitfall is relying solely on your smartwatch data without considering your symptoms. Your SpO2 is just one piece of the puzzle. Pay attention to how you feel and don’t hesitate to seek medical advice if you’re concerned.

When should you seek medical intervention? If your SpO2 consistently remains below 85%, or if you experience severe symptoms like shortness of breath at rest, confusion, or loss of coordination, it’s time to seek medical attention. Denver has several excellent hospitals and urgent care centers that are experienced in treating altitude sickness. Consider visiting the UCHealth University of Colorado Hospital or the Rose Medical Center. Many urgent care facilities, like those operated by Centura Health, also offer altitude sickness treatment.

Remember, acclimatization is a process, not an event. It takes time for your body to adjust to the lower oxygen levels at higher altitudes. By using your smartwatch to monitor your SpO2 levels and adjusting your behavior accordingly, you can proactively manage altitude sickness and enjoy your time in Denver. Don’t let the altitude ruin your trip; be prepared, be informed, and be proactive.