Insulin resistance lies at the heart of many of today's most common chronic health conditions. It is a major contributor to type 2 diabetes, metabolic syndrome, obesity, cardiovascular disease and even some forms of cognitive decline.

A series of studies led by Australian researcher Dr David Wilkinson has produced some of the strongest human evidence that HBOT can improve insulin sensitivity. Published between 2012 and 2020, these three studies build upon one another to tell a compelling scientific story.

Although HBOT is not a treatment for diabetes, these findings suggest it positively influences one of the fundamental physiological processes that contribute to metabolic disease.

Why Insulin Sensitivity Matters

Every time we eat carbohydrates, they are broken down into glucose, which enters the bloodstream. Insulin, produced by the pancreas, acts like a key, allowing glucose to move from the blood into our muscles, liver and other tissues where it is used for energy or stored for later use.

When cells become less responsive to insulin—a condition known as insulin resistance—the pancreas must produce increasing amounts of insulin to achieve the same effect. Over time, blood glucose levels begin to rise, increasing the risk of developing type 2 diabetes and a range of chronic diseases.

Improving insulin sensitivity allows the body to use insulin more efficiently, helping to regulate blood glucose while reducing the stress placed on the pancreas.

The Three Wilkinson Studies

Rather than being isolated pieces of research, the three Wilkinson papers answer three important questions:

• Does HBOT improve insulin sensitivity?

• Does it work in people with type 2 diabetes as well as those without diabetes?

• Does the improvement occur during treatment, and is oxygen itself responsible?

Together, they provide a remarkably consistent picture.

Study One (2012): The First Human Evidence

Hyperbaric oxygen therapy improves peripheral insulin sensitivity in humans

Published in Diabetic Medicine in 2012, this was the first study to directly demonstrate that HBOT improves insulin sensitivity in humans.

The researchers used the hyperinsulinaemic–euglycaemic glucose clamp, regarded as the gold standard for measuring insulin sensitivity.

Rather than simply measuring blood glucose, this sophisticated technique quantifies exactly how much glucose the body requires to maintain stable blood sugar while insulin levels are kept constant.

What did they find?

Following a single HBOT session, participants demonstrated a significant increase in peripheral insulin sensitivity.

This was an important finding because previous observations had noted that blood glucose often fell during HBOT, but nobody had clearly shown why.

The study suggested that HBOT wasn't simply lowering glucose temporarily—it was actually making body tissues respond more effectively to insulin.

That was an exciting discovery.

Study Two (2015): Does It Help People with Diabetes?

Hyperbaric oxygen therapy increases insulin sensitivity in overweight men with and without type 2 diabetes

The second study (published in Diving and Hyperbaric Medicine) expanded considerably on the original findings.

Rather than studying healthy volunteers alone, researchers recruited overweight men both with and without type 2 diabetes.

Participants underwent HBOT before researchers again measured insulin sensitivity using the glucose clamp technique.

The results

The findings were remarkably consistent.

Both groups experienced significant improvements in insulin sensitivity following treatment.

Perhaps even more interesting, the improvement remained measurable approximately 30 minutes after participants left the hyperbaric chamber.

This suggested that the metabolic changes produced by HBOT did not disappear the moment pressure returned to normal.

The researchers also observed changes in inflammatory markers, raising the possibility that reducing chronic inflammation may contribute to improved insulin action.

Study Three (2020): Is It the Oxygen or the Pressure?

Hyperbaric oxygen but not hyperbaric air increases insulin sensitivity in men with type 2 diabetes mellitus, published in Diving and Hyperbaric Medicine.

By 2020 another important question remained unanswered.

Was the improvement caused simply by being under pressure?

Or was breathing oxygen under pressure responsible?

To answer this, Wilkinson's team measured insulin sensitivity during the HBOT session itself.

Again using the glucose clamp technique, they demonstrated that insulin sensitivity increased while participants remained inside the chamber.

Their work strongly suggested that hyperoxia—the increased availability of oxygen—rather than pressure alone, was responsible for the physiological effect.

This distinction is important because it helps explain why HBOT appears to influence metabolism differently from simply sitting inside a pressurised chamber breathing normal air.

What Happens Inside the Body?

Although these studies focused on measuring insulin sensitivity rather than explaining every underlying mechanism, they point toward several biological processes that are now being explored by researchers worldwide.

Current evidence suggests HBOT may:

• Improve mitochondrial function and energy production

• Reduce chronic inflammation

• Improve blood flow to insulin-sensitive tissues

• Enhance insulin signalling pathways within muscle cells

• Increase glucose uptake by skeletal muscle

• Stimulate beneficial cellular responses through controlled oxidative signalling (sometimes called mitohormesis)

Rather than causing harmful oxidative stress, carefully dosed hyperoxia appears to trigger the body's own protective and adaptive mechanisms.

This concept has become one of the most fascinating areas of modern HBOT research.

How Large Was the Improvement?

Across the Wilkinson studies, insulin-mediated glucose uptake improved by approximately 20–30% following HBOT.

For a single, non-drug intervention, this represents a substantial acute physiological effect.

It is important to note, however, that these measurements were obtained using highly controlled laboratory methods rather than routine blood glucose testing.

This does not mean HBOT lowers blood glucose by 20–30%.

Instead, it means the body's tissues became significantly more responsive to insulin.

More Recent Research Supports These Findings

Since Wilkinson's work, additional studies have reinforced the connection between HBOT and metabolic health.

Researchers have demonstrated improvements in:

• Whole-body insulin sensitivity

• Liver insulin sensitivity

• Fat tissue insulin sensitivity

• Skeletal muscle mitochondrial function

• Cellular energy production

These findings suggest that HBOT influences multiple aspects of metabolism rather than acting through a single pathway.

What These Studies Do Not Show

As encouraging as the research is, it is equally important to understand its limitations.

The Wilkinson studies do not demonstrate that HBOT cures diabetes.

They also do not tell us:

• the ideal treatment pressure

• the optimal number of sessions

• how long improvements persist after treatment

• whether HbA1c improves over months

• which patient groups benefit the most

Much larger clinical trials are still required before HBOT could be considered part of routine metabolic care.

Why This Research Matters

One of the most exciting aspects of these studies is that they demonstrate HBOT may influence one of the fundamental drivers of chronic disease—insulin resistance.

Improving insulin sensitivity has implications far beyond diabetes.

Insulin resistance is increasingly recognised as a contributor to:

• cardiovascular disease

• obesity

• fatty liver disease

• chronic inflammation

• cognitive decline

• healthy ageing

While HBOT should never replace exercise, nutrition or stress reduction practices, it may eventually become an important complementary therapy for supporting metabolic health.

The Take-Home Message

Viewed together, the three Wilkinson studies tell a remarkably consistent story.

First, they demonstrated that HBOT improves insulin sensitivity.

Next, they showed that the improvement occurs in overweight individuals both with and without type 2 diabetes and continues beyond the treatment session.

Finally, they confirmed that the improvement occurs during HBOT itself and appears to be driven primarily by increased oxygen availability rather than pressure alone.

Taken together, these studies represent one of the strongest bodies of evidence that hyperbaric oxygen therapy can acutely improve insulin sensitivity in humans.

As research continues, scientists are now asking the next important question:

Can repeated HBOT sessions produce long-term improvements in metabolic health?

The answer may have significant implications for the future management of insulin resistance and type 2 diabetes.

References

Wilkinson D, Chapman IM, Heilbronn LK. Hyperbaric oxygen therapy improves peripheral insulin sensitivity in humans. Diabetic Medicine. 2012.

Wilkinson D, Nolting M, Mahadi MK, Chapman IM, Heilbronn LK. Hyperbaric oxygen therapy increases insulin sensitivity in overweight men with and without type 2 diabetes. Diving and Hyperbaric Medicine. 2015.

Wilkinson D, Szekely S, Gue B, Tam CS, Chapman IM, Heilbronn LK. Assessment of insulin sensitivity during hyperbaric oxygen treatment. Diving and Hyperbaric Medicine. 2020.

Wilkinson D, Chapman I, Heilbronn L. Hyperbaric oxygen but not hyperbaric air increases insulin sensitivity in men with type 2 diabetes mellitus.  Diving and Hyperbaric Medicine. 2020