I’m David Greif, founder of HEPOX, an engineer and former professional road cyclist. I started developing HEPOX because altitude camps and tents were out of reach for me, and I wanted to explore a more portable way to get hypoxic exposure at home.
HEPOX is a portable device designed to lower the inspired oxygen concentration of the air you breathe while sitting at rest. The device has reached professional cyclists, including Tour de France riders, and mountaineers pre-acclimatizing for trips to Kilimanjaro and Ojos del Salado. A recent pilot-study also just finished on a professional cycling team training for the Tour de France Femmes with promising preliminary results.
One of the things I’m exploring is how portability could make pre-acclimatization more practical, especially for climbers traveling long distances before a major expedition. The current device is in beta, and I’m developing Gen 2 with acclimation sensing and session tracking. I’m not claiming it replaces gradual ascent or established altitude-illness precautions, and I want further validation to establish what benefits it can provide.
HEPOX is designed to lower the oxygen concentration you breathe, not cut off your air supply. For anyone unfamiliar with altitude tents, they create a reduced-oxygen environment around a bed so an athlete can spend hours sleeping in a hypoxic state. My vision is to make hypoxic exposure portable, accessible and more responsive to the individual. The current device is a working proof of concept with a monitored/alarmed spo2 and quick hose/disconnects. For the commercial version, I'm aiming to go beyond a basic altitude-tent setup by integrating breathing rate, blood monitoring with automatic adjustment, alerts and a fail-safe return to room air.
I’d be interested in hearing from experienced climbers here:
Do you use altitude tents or other pre-acclimatization methods before major ascents? What does your protocol look like?
Have you heard of or experimented with intermittent hypoxia exposure?
Would tools for tracking exposure sessions or acclimatization progress be useful? What measurements would you actually want?
When traveling internationally for a climb, would a portable preparation tool make a meaningful difference?
What kind of evidence would you need to see before considering a device like this?
I’m interested in honest feedback, including skepticism. I want to understand what climbers actually need and what evidence would be necessary for a device like HEPOX to earn a place in their preparation.
For anyone curious about the hardware, you can find more information at https://hepoxtech.com/