Bold truth: training for altitude isn’t about piling up more reps or running faster—it’s about mastering how your body gasps for oxygen at high elevations. Here’s how Olympians prepare for competition where the air is thinner, the scenery is dramatic, and every breath counts.
At the Milano Cortina 2026 Olympics, venues around Cortina d’Ampezzo span a striking vertical range. From the Tesero cross‑country stadium at roughly 830 meters (2,723 feet) up to the Vertigine downhill start at about 2,380 meters (7,808 feet). Lifts reach up to 3,244 meters (10,643 feet) atop Tofana, the highest peak in the Tofane massif of the Dolomites. Other sites sit solidly in high‑altitude territory, including Livigno’s snow park at 1,816 meters (5,958 feet) and the Antholz‑Anterselva biathlon arena at around 1,600 meters (5,249 feet).
At these elevations, the science shifts from sheer strength, speed, and endurance to understanding blood oxygen levels and cardiovascular function, according to Northeastern University extreme medicine experts.
“Above sea level, the air holds less oxygen because atmospheric pressure is lower, so fewer oxygen molecules reach your lungs,” explains Joshua Merson, an associate clinical professor and director of the extreme medicine program at Northeastern University. “To compensate, you breathe faster or deeper to pull more oxygen in, and your heart rate rises to pump more oxygen‑rich blood.”
But for both elite athletes and everyday climbers, ascending to high altitude can be dangerous. If you move too quickly and your body can’t keep up, systems can start to fail, Merson warns.
When oxygen delivery drops—a state called hypoxia—the body triggers an inflammatory response that can disrupt blood pressure regulation, causing fluids to leak into places they shouldn’t. This cascade can quickly lead to altitude sickness, characterized by headaches, nausea, and fatigue—akin to a hangover, but with subtler early warning signs that, if ignored, may escalate into more serious illness.
Hypoxia isn’t only a mountain phenomenon. It can occur on the ground or in oxygen‑controlled environments. Long flights, heat stress, illness, and intense training blocks can temporarily reduce tissue oxygen delivery, notes Sarah Spelsberg, director of U.S. Operations at World Extreme Medicine, who is involved in shaping Northeastern’s extreme medicine courses.
The body responds to hypoxic stress by raising heart rate, shifting metabolism, and prioritizing oxygen for vital organs. The real risk appears when oxygen demand outstrips supply.
Understanding hypoxia helps athletes train smarter. Altitude exposure teaches pacing on tough days, spotting early signs of overreach or illness, and adopting deliberate recovery strategies—adequate sleep, proper hydration, and dialing back intensity when performance wanes. In short, awareness of hypoxia helps athletes separate productive stress from warning signs, reducing injury and burnout while supporting long‑term performance.
How do clinicians know when hypoxia is starting to derail an athlete?
“In the field, I look for subtle cues,” Merson says. “Someone who’s usually chatty becomes quiet; a field‑packing pro struggles with gear; a trained athlete suddenly breathes heavily on flat ground. Sometimes the signs are bolder—stumbling or poor coordination—even before headache, nausea, or other classic altitude sickness symptoms show up.”
Two notable altitude incidents from the 1968 Mexico City Olympics, held at about 2,250 meters (7,382 feet), illustrate the risk. Australian distance star Ron Clarke collapsed unconscious after the 10,000 meters, and U.S. swimmer Suzy Jones, who trained in Colorado Springs to prepare, fell ill during high‑altitude training, later noting altitude’s impact on performance.
Fitness alone doesn’t guarantee protection from altitude sickness. Genetics may also play a role, Merson notes.
Geography matters. In New England, even the highest peaks (for example, Mount Washington at roughly 6,300 feet) stay well below levels that trigger severe altitude stress. By contrast, Colorado routinely features training venues above 10,000 feet, with peaks exceeding 14,000 feet, placing athletes much closer to the threshold where thinner air affects performance and recovery.
