Studies

A pilot study recently published in September 2024 by Naoya Takei and his team investigated whether hypoxic training—that is, training under conditions of reduced oxygen—can improve performance during longer sprints. Of particular interest was the question of whether repeated sprint training in hypoxia (RSH) offers additional benefits compared to training under normal conditions (normoxia).

Results: Although hypoxia training did not lead to a significant improvement in sprint speed during longer sprints (over 10 seconds), it had a notable effect on blood parameters: The lactate concentration after training was significantly lower than during normal training. This suggests that hypoxic training may improve the body’s ability to clear lactate, leading to faster recovery and improved endurance.

Conclusion: While hypoxia training offers no additional benefits for longer sprints, it could still play an important role in recovery and long-term performance improvement by optimizing lactate metabolism.

These findings are particularly interesting for coaches and athletes who want to further improve their endurance and recovery after intense exercise.

Read the full study here.

A new study by Thibaut Legoy and Eric Fruchart, published in September 2024, examines the ethical issues surrounding the organization of hypoxic training camps by coaches. Hypoxic training, in which athletes train under conditions of oxygen deprivation to enhance their performance, is controversial. The aim of the study was to determine how various factors—such as the training goal, fairness, planning and monitoring, and the method used—influence the acceptance of such a training camp.

A total of 216 people participated in the study, including athletes and non-athletes. They evaluated 36 different scenarios in which these factors were combined in various ways. The analysis revealed four different ethical stances:

1. Somewhat acceptable—26% of participants
2. Acceptable if monitored—38% of participants
3. Always acceptable—20% of participants
4. Never acceptable without expert planning and medical supervision—16% of participants

Interestingly, male participants and athletes were more likely to accept hypoxic training, while women and non-athletes tended to be skeptical. The study confirms that hypoxic training is not at odds with the spirit of sportsmanship and could help sports organizations improve their communication regarding the ethical value of this training approach.

These findings provide a valuable foundation for ethical discourse and public outreach in sports.

Read the full study here.

In a study published in August 2025 in the *European Journal of Applied Physiology*, researchers examined the effect of intermittent hypoxia (IHE) following resistance training on short-term vascular function in untrained men. This study presents an innovative approach to supporting vascular health after strength training.

Study Design: A total of 13 male students who had undergone fitness training, aged approximately 20 years and with a BMI of approximately 23.6, participated in the study:

• Resistance exercise followed by normoxia (RE, FIO2 = 21%)
• Resistance exercise followed by intermittent hypoxia (REH1, alternating FIO2 = 13.6% and 21%)
• Resistance exercise followed by mild intermittent hypoxia (Re-H2, alternating FIO2 = 15.8% and 21%)

Study results:

• Stabilized endothelial function: Following exercise under normoxic conditions, FMD (flow-mediated dilation) decreased significantly; however, under conditions of intermittent hypoxia, FMD remained stable for 60 minutes post-exercise.
• Arterial stiffness: This decreased after exercise + normoxia and after exercise + mild hypoxia, but not after exercise + more severe hypoxia.
• Blood flow: Blood flow increased significantly under all conditions, with greater increases observed under hypoxic conditions compared to normoxic conditions.

Conclusion:

This study shows that a brief period of intermittent hypoxia following strength training can help maintain vascular health. While vascular function temporarily deteriorated after training under normal oxygen conditions (normoxia), it remained stable under alternating oxygen conditions.

This means that if you induce a controlled period of hypoxia after intense exercise, you can support the recovery processes of the blood vessels and improve regeneration.

Read the full study here.

A study by Soo et al. in *Experimental Physiology* (February 2025) examined how hypoxia during various phases of high-intensity interval training (HIIE) —specifically during exercise, recovery, or both phases—affects exercise performance, metabolic responses, and perceptual responses in overweight, physically inactive individuals.

Study Design: The study included 18 overweight, sedentary adults with an average age of approximately 31 years and a BMI of approximately 28.7:

• There were four test conditions:
  • 1. NN: Normoxia: (normal oxygen levels) during exercise and rest
  • 2. HH: Hypoxia (approx. 14%O2, equivalent to an altitude of 3,000 m) during work and rest
  • 3. NH: Hypoxia only during recovery phases
  • 4. HN: Hypoxia only during the work phases
• Protocol: 6 sets of 1 minute of cycling (RPE = 16/20 = “very strenuous”) followed by 4 minutes of active recovery (RPE = 10/20).

Study results:

• Performance: Performance was lowest under conditions of continuous hypoxia (HH). Under conditions of intermittent hypoxia—particularly when it occurred only during recovery (NH) —performance remained nearly the same as under normoxia.
• Heart rate: Was highest during hypoxia in the exercise phases (HN).
• Lactate: Slightly higher under normoxia and hyperoxia (HN), and somewhat lower under hypoxia during recovery (NH).
• Muscle oxygenation: Significantly greater fluctuations during HN, indicating a more severe lack of oxygen in the muscles during exercise.
• Subjective exertion: Similar values across all conditions—hypoxia was therefore not perceived as more strenuous.

Conclusion:

Intermittent hypoxia— that is, alternating phases of normal and reduced oxygen levels —can avoid the drawbacks of continuous hypoxia training. If hypoxia is applied only during recovery phases, training performance remains high while still triggering the desired oxygen adaptations.

This form of training could therefore be an effective, time-saving method for harnessing the physiological benefits of hypoxia training—especially for overweight or untrained individuals— without reducing their exercise tolerance.

Read the full study here.

We would like to present an exciting study from October 2024 that examines an innovative approach to treating post-acute COVID-19 sequelae (PASC), also known as Long COVID.

Researchers have analyzed, for the first time, the effect of intermittent hypoxia therapy (IHT) on shortness of breath and fatigue in patients with long COVID. A total of 95 participants took part in the randomized, controlled study. One group received IHT, which involved alternating 5-minute periods of low oxygen supply and normal air. The other group received normoxia treatment.

Study findings:

• Improved lung function: increase in forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1)
• Longer walking distances: The 6-minute walk distance (6MWD) improved significantly
• Less shortness of breath and fatigue: Participants in the IHT group reported greater subjective improvements

The study shows that IHT could be safe and potentially helpful in improving the quality of life for patients with long COVID. Larger studies are needed to further confirm these findings.

Read the full study here.

A new meta-analysis by Oleg Glazachev and his team examined the safety and efficacy of intermittent hypoxia training (IHT) as a rehabilitation strategy for patients with cardiovascular diseases. This training, which involves repeated phases of oxygen deprivation (hypoxia) and normal breathing (normoxia) or excess oxygen (hyperoxia), is increasingly viewed as a promising approach for the prevention and treatment of heart disease.

Results: An analysis of 14 studies involving a total of 431 patients showed significant improvements in cardiovascular parameters: The resting heart rate decreased by an average of 5.35 beats per minute, systolic blood pressure by 13.72 mmHg, and diastolic blood pressure by 7.88 mmHg. These results suggest that IHT is an effective method for lowering heart rate and blood pressure.

Conclusion:

Hypoxia training could be a safe and effective adjunct to rehabilitation for cardiovascular diseases. However, further studies are needed to better understand the optimal training protocols and long-term effects.

Read the full study: here

A new pilot clinical study by Doehner et al. (2024) has shown that intermittent hypoxia-hyperoxia training (IHHT) can significantly improve physical performance and well-being in patients with Long COVID. Many affected individuals suffer from shortness of breath, weakness, and fatigue, which delays their quality of life and return to work. IHHT could be a promising addition to rehabilitation.

Study design:
A total of 145 patients (74% women, average age 53 years) participated in the study. They were divided into two groups:

• IHHT group (n = 70): In addition to standard rehabilitation, participants received IHHT sessions three times a week involving hypoxic (10–12% O₂) and hyperoxic (30–35% O₂) breathing.
• Control group (n = 75): Received only standard rehabilitation.

Results:

• Walking test (6-minute walk test): IHHT patients improved their walking distance 2.8 times more than the control group (+91.7 m vs. +32.6 m, p < 0.001).
• Climbing stairs: The time taken to climb stairs improved 3.7 times more in the IHHT group (-1.91 s vs. -0.51 s, p < 0.001).
• Symptoms: IHHT significantly reduced shortness of breath and fatigue and improved quality of life.
• Blood test results: Lower blood pressure and heart rate, as well as higher hemoglobin levels, in the IHHT group.
• Safety: No side effects have been observed with IHHT.

Conclusion:

The study shows that IHHT can be a safe and effective method for improving exercise tolerance and quality of life in patients with Long COVID. The therapy could become an important component of future rehabilitation programs.

Read the full study: here

A study by Zhao et al. (April 2025) investigated whether short, intermittent periods of hypoxia (brief reductions in oxygen followed by room air) during an oral glucose tolerance test improve insulin sensitivity in adults with type 2 diabetes and a healthy control group.

Study Design: A total of 18 participants took part in the study and were divided into two groups: nine adults with type 2 diabetes and nine healthy adults:

• After consuming a glucose solution (two-hour OGTT), participants underwent either an intervention protocol consisting of eight cycles of four minutes of hypoxia (O₂ saturation target ~80%), each interrupted by periods of room air, or a sham normoxia control (four minutes of normoxia each) was used.
• Measurement of glucose and insulin concentrations and calculation of insulin sensitivity.

Study results:

• In the diabetes group, intermittent hypoxia— compared with normoxia —led to a smaller increase in insulin levels following glucose intake.
• Insulin sensitivity was significantly higher under hypoxic conditions in the diabetes group compared to normoxic conditions.
• In the group with normal blood glucose levels, hypoxia had no significant effect on insulin sensitivity.

Conclusion:

The results suggest that brief, repeated episodes of hypoxia can acutely improve insulin sensitivity in adults with type 2 diabetes. No such effect was observed in the healthy control group.

Read the full study here.