Hypoxia Protocol for Increased Endurance and/or Altitude Adaptation

Why Use This Protocol?

This protocol is designed for endurance athletes, high-altitude athletes, or any individuals aiming to increase their red blood cell (RBC) mass, improve oxygen transport, and improve endurance athletic performance without the use of WADA banned substances.

Classically, altitude training blocks or altitude exposures such as altitude tents have been a staple for endurance athletes to improve performance. However, these methods have their drawbacks; training at altitude reduces the quality of higher intensity sessions, and altitude tents can reduce sleep quality and recovery. This protocol can ben done in 2-4 hours per day, and can be done while peforming any daily activity that doesn't require you to move to many different rooms or locations (e.g., working at a computer, reading or watching television, etc).

This protocol can be used anywhere, at any time, once you have the equipment. It is designed to be used in conjunction with your normal training schedule, allowing you to maintain high-quality training while still reaping the benefits of altitude exposure. Even when used while living and/or training at altitude, this protocol will provide benefits above and beyond what can be achieved through altitude exposure alone.

By combining controlled hypoxia sessions with intermittent isocapnic breathing, this approach:

• Stimulates erythropoietin (EPO) production and reticulocyte response
• Enhances red blood cell mass for improved endurance
• Enhances iron utilization ceruloplasmin production
• Maintains cerebral perfusion and reduces central fatigue during hypoxia

Equipment Needed

• Any altitude generator + mask that can simulate at least 4000m of altitude, or low enough oxygen concentration to sustain extended bouts of O2 saturation ~80% (ex: Hypoxico Sierra 100)
• An Isocapnic breathing device
• A Pulse Oximiter that can accurately measure O2 saturation
• Optional: Hemoglobin Monitor to track red blood cell response over time without the need for frequent blood testing. Click on the Hemoglobin Tool to use this meter to estimate other red blood cell metrics. (example: Hemoglobin Test Meter)

Note: All positive physiological adaptations require adequate recovery and nutritent status. Ensure adequate levels Iron, Vitamin B12, Folate, Copper, Zinc, Vitamin B2, Vitamin B6, Iodine, Selenium, and Vitamin C, A and E. Hypoxia is a training stress, so additional recovery will be needed.

The Protocol

Perform 2 sessions per day of hypoxia using a Hypoxico Sierra 100 mask set to 4200ft altitude, each session lasting 2 hours. Incorporate an isocapnic bag for brief intervals to maintain CO₂ levels and optimize adaptation.

During each 2-hour session, there will be Three 3-minute breaks using the isocapnic bag. During these breaks, simply breathe into the isocapnic bag normally, then immediately resume the hypoxic mask. These breaks should occur at the following times:

• 20 minutes
• 60 minutes
• 100 minutes

Options for less frequent hypoxic sessions, in order of efficacy:

• 2x2-2:30hr sessions/day (most effective)
• 1x2hr sessions + 1x:90min session
• 2x:90min sessions
• 1x3hr session
• 1x2hr session
• 1x:90min session (minimum dose for possible adaptation)

Long-Term Protocol Use

• 3 weeks ON: Perform 2×/day sessions, 5–7 days/week
• 1 week OFF: Full rest from hypoxia to allow recovery and adaptation
• Repeat cycles as needed for progressive red blood cells improvements

The Science

The hypoxic stimulus increases HIF-1α stabilization, triggering EPO mRNA transcription, which leads to elevated reticulocyte production and increased RBC mass. However, continuous hypoxia can lead to CO₂ washout (hypocapnia), which blunts HIF-1α signaling and reduces cerebral perfusion.

Intermittent use of an isocapnic bag restores CO₂ levels, maintaining cerebral blood flow and amplifying the hypoxic drive. Studies have shown that combining hypoxia with CO₂ maintenance increases EPO area-under-curve by approximately 30–50%, leading to superior hematologic gains:

• Wojan et al. (2021): Peak EPO occurs at 90–120 min hypoxia, with diminishing returns beyond. [link]
• Turner et al. (2016): Altitude of 4,200m for 2 hours provided the greatest effect, with no additional benefits beyond. [link]
• Garcia, Hopkins & Powell (2000): Normobaric hypoxia with preserved PETCO2 improves HIF-1α and erythropoietic signaling. [link]
• Serebrovskaya et al. (2011): Intermittent hypoxia + CO2 recovery breathing led to enhanced hematopoietic response. [link]
• Verges et al., 2015: Maintaining PETCO2 (preventing excess hypocapnia) during hypoxia produces 30–50% greater EPO AUC vs hypocapnic hypoxia. [link]
• Millet et al. 2010: Split hypoxia + brief reoxygenation improves adaptation over long continuous hypoxia. [link]
• de Abreu et al. (1997): CO2 rebreathing restores cerebral blood flow during acute hypoxia. [link]

This protocol is synthesized from these studies and field use at elite sports training centers (e.g., AIS, INSEP).