IHHT: How Intermittent Hypoxia-Hyperoxia Training Boosts Your Health from the Inside Out

What is IHHT? Well, if you’re looking for a way to boost your metabolic health, build stress resilience, and support your brain and body at a cellular level, Intermittent Hypoxia-Hyperoxia Training (IHHT) could be the game-changer you didn’t know existed.

In this post, I’ll walk you through what IHHT is, how it works, and why it’s such a powerful tool for building both physical and mental resilience — safely and effectively.

What Is IHHT?

IHHT is a safe, well-researched approach to oxygen therapy that helps your body adapt to the conditions you’d experience at high altitude — but without leaving your chair.

By breathing cycles of low oxygen (hypoxia) and higher oxygen (hyperoxia) — typically between 11–16% and 21–35% oxygen respectively — your body is gently challenged to improve its efficiency, resilience, and repair systems.

At altitude, your body has to learn how to perform better with less oxygen. IHHT triggers the same powerful adaptation response, delivering all the health benefits of altitude training without the physical strain.

During IHHT:

• Your respiratory, cardiovascular, immune, muscular, and nervous systems all work harder to adapt and strengthen.

• Underperforming cells are naturally renewed, leading to the creation of new, healthier mitochondria.

• Your overall metabolic function is enhanced across all tissues and systems.

In short: you become more resilient — right down to the cellular level.

Why I Offer IHHT: Two Core Reasons

There are two main reasons I include IHHT in my programs:

1. Improving the Respiratory System
   IHHT naturally encourages slower, deeper breathing by helping your body become more tolerant of lower oxygen levels and higher CO₂ levels. This improves your breathing efficiency without you needing to consciously “train” it.

2. Boosting Mitochondrial Function
   Healthy mitochondria are essential for energy, resilience, and repair throughout the entire body and brain. IHHT helps renew and revitalise your mitochondria, setting a stronger foundation for overall health.

Together, these two adaptations lead to consistent improvements in:

• Stress resilience

• Aerobic performance

• Hormonal balance

• Physiological repair including deeper sleep and reduction in oxidative stress

• Stronger metabolic health

As Professor Vadim Gladyshev from Harvard University has said:

“The most important thing for long-term health is to build up the cells’ adaptability to hypoxia.”

What Can IHHT Help With?

IHHT is far more than just a breathing exercise. Scientific research shows it supports a wide range of health benefits, including:

• Brain health

• Cellular renewal

• Oxygen efficiency

• Anti-inflammatory effects

• Cardiovascular health

• Mood and emotional regulation

Dr. Brodmann-Peschke of Cellgym put it clearly:

“Flexibility in the face of hypoxia is what leads cells to be resistant to stress and disease.”

IHHT helps you build that flexibility.

While I chose IHHT for very specific reasons in my mental health practice, IHHT improves function in almost every system of the body as highlighted below.

How IHHT Works: Stress and Recovery Cycles

IHHT sessions involve breathing in alternating cycles of low-oxygen and high-oxygen air.

This delivers controlled cycles of challenge (hypoxia) and recovery (hyperoxia) — essentially training your body to handle stress and recovery more effectively at a deep physiological level.

When you breathe lower oxygen air:

• Your blood oxygen saturation (SpO₂) drops slightly.

• Your heart rate responds, rising slightly as your body works harder.

When you breathe high oxygen air:

• Your SpO₂ levels rise back up.

• Your heart rate slows as your body recovers.

This gradual, repeated exposure trains your resilience — similar to how lifting weights strengthens muscles.

What Progress Looks Like

Everyone adapts to IHHT at their own pace. For example:

• Athletes and healthy individuals often adapt quickly, showing strong, smooth rises and falls in oxygen saturation and heart rate. Below you can see the feint blue line shows the rise and fall of the oxygen levels. The green line is the Blood oxygen level (SPO2) and the red line is the heart rate. They are well co-ordinated and adaptive. As the oxygen levels drop so does blood oxygen level and with this heart rate rises, working harder to pump blood and oxygen around the body. In the recovery (hyperoxia) phase, their SPO2 levels rise quickly and their heart rate lowers. This is as we would expect to see with someone whose body is adapting well.

• Some people (especially those with long-term health issues or who are chronically stressed) may show difficulty  adaptation and need a very gentle, gradual approach.

 

This first graph is of a longer term health condition and does show some rise and fall in blood Oxygen levels but this person is unable to rise to full oxygenation in the recovery phase. Training will need to proceed gently and slowly in this case.

In summary: good adaptability shows up in graphs where:

• Blood oxygen levels drop appropriately during hypoxia and rise during hyperoxia.

• Heart rate rises during the challenge phase and falls during recovery.

The key is that your body learns — and each session builds your adaptability over time.

Mitochondria: Why They Matter

Mitochondria are tiny structures found in nearly every cell in your body. They’re often called the “powerhouses” of the cell because they generate ATP — the energy currency your cells need to function.

But mitochondria do far more than just create energy:

• They regulate your metabolism.

• They oversee cell renewal and death.

• They help determine how well your entire body and brain cope with stress.

Healthy mitochondria = healthy metabolism = healthy life.

When your cells can no longer adapt effectively to stress (including oxygen stress), mitochondria become dysfunctional — leading to fatigue, disease, mood instability, and reduced resilience.

IHHT is a way to rehabilitate your mitochondria naturally — encouraging old, dysfunctional mitochondria to be replaced with newer, stronger ones.

This process benefits every system in the body: brain, heart, muscles, immune system, and more.

How Mitochondria Become Dysfunctional

Mitochondrial dysfunction can be either inherited or acquired. Some main causes include:

• Genetic mutations (especially mitochondrial DNA mutations)

• Oxidative stress (too many free radicals damaging cells)

• Aging (natural decline over time)

• Environmental toxins (pollutants, poor diet, chemical exposures)

• Chronic infections and diseases (e.g., Parkinson’s, Alzheimer’s)

When mitochondria can’t do their job properly, cells lack the energy needed to function — leading to a cascade of health issues, especially in energy-hungry organs like the brain, heart, and muscles.

Mitochondria and Mental Health: A New Frontier

Over the last 20 years, research into mitochondria’s role in mental health has exploded.

Chronic stress, early life adversity, and environmental factors can all impair mitochondrial function. And when mitochondria are underperforming, it impacts how the brain regulates stress, emotion, and resilience.

Dr. Christopher Palmer, Harvard Psychiatrist and author of Brain Energy, is at the forefront of this research. His work shows how mitochondrial dysfunction links many mental health struggles — from depression to anxiety to more complex conditions.

In other words:
Supporting your mitochondria isn’t just about physical health.
It’s about mental and emotional vitality, too.

Final Thoughts

IHHT offers a practical, powerful way to:

• Boost your resilience

• Improve your breathing and energy systems

• Renew your mitochondria

• Strengthen your mind-body connection

It’s a gentle, scientifically backed method to train your body and brain for a healthier, more adaptable future — from the inside out.

If you’re curious about how IHHT might help you, feel free to reach out — I’d be happy to chat and answer any questions.