Reinhold Messner and Peter Habeler were the first people to climb Mount Everest without supplemental oxygen, reaching the summit at 1:15 p.m. on May 8, 1978. Before their climb, many physiologists believed the human body simply could not survive at 8,848 meters (29,029 feet) without bottled oxygen. They proved otherwise, and in the decades since, a small number of elite mountaineers have repeated the feat.
The 1978 Breakthrough
Messner, an Italian from South Tyrol, and Habeler, an Austrian, set off from Camp II on the Nepalese side of Everest on May 6, 1978. Two days later they stood on the summit. They spent roughly 15 minutes at the top before beginning a laborious descent, stumbling back into Base Camp on May 10. Messner later described the experience in a now-famous line: “I am nothing more than a single narrow gasping lung, floating over the mists and summits.”
The achievement was genuinely surprising at the time. Atmospheric pressure on the summit is about one-third of sea level, which means each breath delivers far less oxygen to the blood. Scientists had long debated whether a human could remain conscious, let alone climb, in those conditions. Acclimatization over many weeks changes the body in measurable ways: breathing rate increases, the concentration of red blood cells rises, and the blood itself becomes more efficient at carrying oxygen. For Messner and Habeler, weeks of gradual altitude gain made the final push possible.
Ang Rita Sherpa: The Record Holder
No one has matched the oxygen-free record of Ang Rita Sherpa. The Nepali climber summited Everest 10 times without supplemental oxygen, in 1983, 1984, 1985, 1987, 1988, 1990, 1992, 1993, 1995, and 1996. His 1987 ascent stands out as the only successful winter summit of Everest ever completed without bottled oxygen, a feat no one has repeated. Ang Rita passed away on September 21, 2020.
The First Woman to Summit Without Oxygen
New Zealander Lydia Bradey became the first woman to reach Everest’s summit without supplemental oxygen in October 1988, climbing solo. But her achievement was mired in controversy for years. Bradey didn’t have a permit for the route she climbed, and to protect the team from a potential ban by the Nepalese government, her teammates Rob Hall and Gary Ball publicly said she hadn’t reached the top. When Nepal threatened Bradey with a 10-year climbing ban, she retracted her own claim, only to reassert it later. Her summit is now recognized.
Notable American Achievements
The story of American women on Everest without oxygen carries a tragic dimension. In 1998, Francys Arsentiev, a 40-year-old Hawaiian-born climber, successfully reached the summit without supplemental oxygen alongside her husband Sergei. Both died during the descent in separate incidents. Some in the climbing community consider Francys the first American woman to climb Everest without oxygen.
Melissa Arnot became the first American woman to both summit and survive the descent without supplemental oxygen on May 23, 2016. That distinction matters: statistically, the descent is when most Everest deaths occur, and forgoing oxygen makes the return far more dangerous than the climb up.
Recent Records
Climbers continue to push boundaries. During the 2024 season, Polish climber Piotr Jerzy Krzyzowski became the first person to summit both Lhotse and Everest without supplemental oxygen in a single push, completing both peaks in 1 day, 23 hours, and 22 minutes. Slovakian Lenka Polackova became the tenth woman to summit Everest without supplemental oxygen, and Indian climber Skalzang Rigzin also completed the feat that season.
Why It’s So Dangerous
Climbing Everest without bottled oxygen is not just harder. It is dramatically more lethal. A study published in JAMA covering summits between 1978 and 1999 found that 1 in 12 climbers who summited without supplemental oxygen died during the descent, compared with 1 in 34 among those using bottled oxygen. That’s nearly three times the fatality rate.
The danger concentrates on the way down. Above roughly 8,000 meters, in what climbers call the “death zone,” the body deteriorates rapidly. Without supplemental oxygen, climbers move slower, think less clearly, and have a narrower margin for error if weather changes or exhaustion sets in. The body’s acclimatization can sustain consciousness and movement for a limited window, but that window is shorter and more fragile than most people realize. Every extra hour spent at extreme altitude compounds the risk of cerebral or pulmonary edema, frostbite, and fatal exhaustion.
This is why the list of successful oxygen-free summits remains remarkably short. Of the thousands of people who have stood on Everest’s summit, only a few hundred have done so without bottled oxygen. It remains one of the most exclusive achievements in mountaineering.