Lisa Tamati sits down with Dr Scott Sherr — internal medicine physician, hyperbaric specialist, and co-founder of Health Optimization Medicine — to go deep on everything hyperbaric oxygen therapy. From stem cell release to methylene blue, this conversation covers the nuances most clinics won't tell you.

Watch the full episode here: Pushing The Limits Podcast with Dr Scott Sherr

What Is Hyperbaric Oxygen Therapy, Really?

Most people know HBOT involves oxygen and a pressurised chamber. But Dr Sherr breaks it down into three distinct mechanisms that most people — and many practitioners — miss.

First, you're dramatically increasing the oxygen dissolved in your blood plasma. At sea level, very little oxygen travels in the plasma itself — it's almost all carried on red blood cells. Under hyperbaric pressure, you can drive up to 1,200% more oxygen into circulation via the plasma alone. That's a physiological shift that nothing else replicates.

Second, you're creating a controlled oxidative stress response — reactive oxygen species that, like exercise, trigger your body to rebuild stronger. Done correctly, this is a feature, not a bug.

Third, the pressure itself has independent effects on your physiology — shearing stress on cells, increased lymphatic and blood flow, stem cell release, and vascular remodelling. This is something even sceptical physicians often overlook: pressure isn't just a delivery mechanism for oxygen. It's therapeutic in its own right.

The downstream effects: reduced inflammation, new blood vessel formation, stem cell mobilisation, immune modulation, and reversal of hypoxic (low oxygen) tissue states.

It's Not "If" — It's "When"

One of Dr Sherr's most important clinical insights is this: almost everyone can benefit from HBOT. The question is whether now is the right time for them.

If someone is chronically inflamed, antioxidant depleted, has severe mitochondrial dysfunction, or a compromised gut — putting them straight into a chamber can make things worse, not better. You're adding an oxidative load to a system that can't neutralise it.

Dr Sherr learned this the hard way early in his career. Patients who weren't ready for HBOT would see minimal improvement, or improve briefly and then relapse once the protocol ended.

The fix? Build the foundations first. Address energy metabolism, nutrients, inflammation, gut health, and hormones. Then introduce HBOT at the right time as a powerful amplifier of an already-improving system.

This is exactly how we approach things at Long Life Hyperbarics. We look at what's going on with the whole person before and around their sessions — not just what happens inside the chamber.

Soft Shell vs Hard Shell: The Real Answer

This is one of the most debated topics in the hyperbaric world. Dr Sherr's position is nuanced and refreshingly honest.

Soft chambers (typically 1.3–1.5 atmospheres) absolutely have real, measurable benefits — particularly for neurological conditions, general wellness, jet lag, exercise recovery, and long COVID. A recent study showed three to four times the stem cell release at just 1.25 atmospheres compared to sea level, even without supplemental oxygen. The pressure alone is doing significant work.

But — and this is important — no amount of time in a mild unit will ever equal the oxygen tension achieved at 2.0 atmospheres and above. Anyone telling you otherwise is not being straight with you. Some conditions genuinely require deeper pressures: serious infections, cancer adjunct protocols, radiation injury, diabetic wounds, traumatic brain injury at depth.

Our chamber at Long Life Hyperbarics operates at 1.5 atmospheres. For the vast majority of our clients — wellness, recovery, neurological support, longevity, long COVID, inflammation — this is highly effective. For specific cases requiring deeper pressures, Dr Sherr's framework of knowing when to refer is something we take seriously.

Before, During and After: The Framework Most Clinics Skip

Dr Sherr has developed a framework over nearly a decade of clinical practice that most hyperbaric clinics never consider: what you do before, during, and after your sessions matters enormously.

Before: Optimise your foundation. This means energy metabolism, nutrient status, inflammation levels, gut health, sleep, and hormones. If you can't make energy efficiently, flooding your system with oxygen is going to create stress without the benefit.

During: For those with neurological or physical rehabilitation goals, there are specific things you can work on inside the chamber to enhance outcomes — cognitive exercises, movement, rehabilitation protocols.

After: How you leverage the window of enhanced oxygenation post-session matters. What you eat, what you supplement, how you move, and how you recover all affect how much benefit you carry forward.

This integrative approach is something I've always believed in — as a functional health practitioner, I've seen too many people get partial results from powerful therapies because the surrounding foundations weren't in place.

A Note on Methylene Blue

We also spent a significant portion of this conversation on methylene blue — a compound Dr Sherr has pioneered through his company Transcriptions. It's a mitochondrial redox cycler that helps cells make energy, detoxify, and fight infection. It's been around for over a century and is showing remarkable results for cognitive decline, mitochondrial dysfunction, and infections including UTIs.

I've been using it personally with my mother, who is in her mid-80s with cognitive decline. Dr Sherr's clinical experience with early-stage Alzheimer's and cognitive impairment patients is compelling.

Getting Transcriptions products into New Zealand is a challenge due to regulations — but it's something we're working on. If you want to see this change, the best thing you can do is ask for it.

Watch the Full Conversation

This summary doesn't do justice to the depth of this conversation. Dr Sherr covers:

• The acute vs chronic HBOT distinction and why it changes everything

• How elite athletes destroy their longevity by underrecovering

• The role of GABA in recovery and why most of us are deficient

• Methylene blue dosing, delivery, and mechanisms in detail

• His nonprofit Home Hope and the practitioner training programme

• What to look for when choosing a hyperbaric clinic

Watch here: Pushing The Limits — Dr Scott Sherr on HBOT, Methylene Blue and Health Optimisation

Long Life Hyperbarics is New Plymouth's specialist hyperbaric oxygen therapy and red light therapy clinic, founded by Lisa Tamati. Sessions from $95. By appointment only — call 021 844 743 or visit longlifehyperbarics.com.

Lisa Tamati is a functional health practitioner, former elite ultra-endurance athlete, and host of the Pushing The Limits podcast with 500,000+ downloads. Her longevity supplements are available at shop.lisatamati.com.