Can Pure Oxygen Turn Back Your Biological Clock? Petra Jurić’s HBOT Journey

Breathing oxygen as a therapy may sound strange at first. After all, we breathe oxygen every second of our lives. But the air around us is not pure oxygen. It is mostly nitrogen, with oxygen making up only about 21%.

Hyperbaric oxygen therapy, or HBOT, is different. During a session, a person breathes close to 100% oxygen in a pressurized chamber, allowing more oxygen to dissolve into the blood plasma and reach tissues throughout the body. But how do these changes translate into biological aging biomarkers?

Petra Juric, a GlycanAge specialist, decided to find out. After completing 10 HBOT sessions, she retested her GlycanAge and observed a two-year reduction in biological age, alongside improvements in several glycan indices associated with immune resilience and healthy aging. While this is a single case and not proof of causation, it offers an intriguing glimpse into how biological age may respond to targeted interventions and why measuring those changes matters.

Before we talk about your results, can you explain what Hyperbaric Oxygen Therapy actually is?

Hyperbaric Oxygen Therapy (HBOT) is an advanced treatment in which patients breathe 100% pure oxygen inside a specially designed pressurized chamber, typically at 2.0-2.5 ATA. The increased pressure allows the body to absorb higher levels of oxygen, significantly boosting the amount dissolved in the bloodstream and delivering it deep into tissues that need healing most. This oxygen-rich environment stimulates tissue regeneration, accelerates wound healing, reduces inflammation, and supports the recovery of both acute injuries and chronic conditions, unlocking the body's natural ability to heal, repair, and recover faster.

What are the most common reasons people seek HBOT today? (recovery, performance, chronic conditions, healthy aging)

The most common reasons are for faster recovery, injury healing, chronic conditions, and overall health support. HBOT works by putting the body under higher pressure, which allows much more oxygen, up to around 10 times more than normal breathing, to dissolve in the blood. This oxygen doesn’t just stay in red blood cells; it also dissolves in the plasma, helping it reach deep or poorly supplied tissues. This is particularly important in injuries, inflammation, or long-term conditions where parts of the body don’t get enough oxygen. With more oxygen available, cells can produce energy better, heal faster, and repair themselves more effectively. It also helps grow new small blood vessels, speeds up tissue healing, supports the immune system, and reduces inflammation and oxidative stress. In simple terms, HBOT helps the body heal faster, recover better after surgery, injury or training, support chronic health issues like difficult-to-heal wounds, and improve the body’s ability to fight infection and repair itself.

What interested you personally about HBOT? Why did you decide to try it yourself?

As a high-altitude climber, I’ve experienced altitude sickness and the brutal effects of low oxygen firsthand in the Himalayas. When you’re thousands of meters above sea level and every breath feels insufficient, you quickly realize that oxygen isn’t just air, it’s also performance, recovery, and survival. In a way, I discovered the power of oxygen through its absence. Naturally, that made me curious about the other extreme: what happens when you dramatically increase oxygen availability instead of limiting it? That experience sparked my interest in HBOT.

Going into the protocol, did you have any specific expectations or hypotheses about what might happen to your GlycanAge results?

Honestly, I didn't have any specific expectations or hypotheses about what would happen to my GlycanAge results. I approached the protocol with pure curiosity. I was interested to see whether increasing oxygen availability through HBOT would have any measurable effect on my biological age and recovery markers, but I didn't go in expecting a particular outcome. For me, it was an opportunity to explore, learn, and let the data speak for itself.

Can you walk us through exactly what you did? (number of sessions, frequency, duration, any other lifestyle changes happening simultaneously)

The protocol started with an initial safety session at 1.6 ATA, which was mainly to check how I equalized pressure and to make sure everything was well tolerated. From the second session onward, all treatments were done at a steady 2.2 ATA. Each session lasted 90 minutes in total, including compression and decompression, with 60 minutes spent at the target therapeutic pressure. In the middle of each session, around the 30-minute mark, there was a 5-minute air break where I breathed normal air instead of oxygen. I did two sessions per week consistently throughout the program. The only interruptions were occasional public holidays when sessions didn’t take place. Apart from that, I didn’t change my lifestyle or add anything new, keeping everything else constant to better observe the effects of the HBOT protocol itself. I did 10 sessions in total.

Did you notice any subjective changes before seeing the biomarker results? (energy, recovery, stress resilience, sleep, mental clarity)

Yes, before seeing any biomarker results, I did notice some subtle but meaningful subjective changes. My energy felt more stable throughout the day, especially after training, and my recovery between workouts seemed slightly faster than usual. I also experienced a bit more mental clarity and focus, particularly during physically and mentally demanding days. Sleep felt more consistent as well, and overall I noticed an improved sense of resilience to stress and fatigue. Nothing dramatic overnight, but enough small changes that made me curious to see what the data would eventually show.

Your follow-up GlycanAge showed a two-year reduction in biological age after just 10 HBOT sessions. What was your first reaction, and what stood out most in the data?

The improvement in markers associated with immune resilience. That felt especially important to me because I’m regularly under high physical demands from climbing and training, and I know the immune system can become less efficient under that kind of stress. Seeing those markers improve suggested better overall robustness and recovery capacity, which mattered more to me than any single number on its own.

Which glycan indices improved, and what do those changes potentially suggest?

The main changes were seen across three key glycan indices. Glycan Youth increased, which is considered an anti-inflammatory index and is often associated with a more “youthful” immune profile. At the same time, Glycan Mature decreased, which is typically linked to pro-inflammatory activity, suggesting a reduction in baseline inflammation and improved recovery balance. Additionally, Glycan Median improved, which is connected to immune adaptation, meaning the immune system’s ability to adjust and respond more efficiently to stressors and environmental demands. For a more detailed breakdown of the five glycan indices behind your GlycanAge, check out this article.

From a scientific perspective, why might HBOT influence glycan patterns?

HBOT might influence glycan patterns because it changes how the immune system and inflammation behave over time. When you breathe oxygen under pressure, the body gets more oxygen than normal. This can help reduce low-grade inflammation, improve tissue repair, and change how immune cells communicate. The repeated shifts in oxygen levels during HBOT (high oxygen + short air breaks) also act as a signal for the body to adjust and “re-balance” itself. Because glycans reflect immune system activity, these internal shifts may show up as changes in glycan patterns. They don’t change randomly, they shift depending on whether the body is in a more inflamed, stressed state or a more regulated, recovered state. So in simple terms: HBOT → changes oxygen and stress signals in the body → influences immune system balance → glycan patterns shift as a reflection of that new state.

If someone only looked at conventional blood markers, would they necessarily see these kinds of changes? Why or why not?

Not necessarily. Conventional blood markers tend to capture more immediate or large-scale changes in the body, such as acute inflammation, infection, or major metabolic shifts, so they can remain normal even when subtle biological changes are happening. Glycan patterns, on the other hand, reflect longer-term immune system behavior and chronic inflammatory balance, making them more sensitive to gradual shifts in immune regulation and biological aging. Because of this, someone could experience meaningful changes in glycan profiles while standard blood tests still look largely unchanged, as the two types of markers are capturing different layers of biology. This article goes deeper into why hidden inflammation may not always show up in standard bloodwork.

What's the biggest lesson you've taken away from seeing your own biology respond to an intervention in real time?

The biggest lesson I took away is just how powerful and adaptable our bodies really are. Seeing measurable changes alongside how I felt made it clear that the body is not a fixed system, it’s constantly responding, adjusting, and optimizing itself based on the conditions it’s given. It also gave me the idea that many states we think of as “permanent” may not be as fixed as they seem, but can actually shift over time when the right conditions or stimuli are introduced. It really made me realize how intelligent our bodies are, constantly sensing, adapting, and working to maintain balance in ways we don’t always notice. At the end of it all, it feels like we’re working with a very intelligent system, our biology is intelligent, and our understanding of it is always evolving.

Petra has now completed the first half of her HBOT protocol, with 10 more sessions still to come. Her next GlycanAge test will offer another opportunity to explore whether these early improvements continue over time, making this an exciting longitudinal case study on the relationship between recovery, immune resilience, and biological aging.