Hiatus Hernias, Core Pressure, and Training: What Most People Aren’t Told

Introduction

When people hear the term hiatus hernia, it’s usually framed as a digestive issue — reflux, heartburn, or indigestion. In reality, a significant hiatus hernia can have far wider effects, especially for people who train regularly. Running, lifting, core work, and high-intensity exercise all place demands on breathing and internal pressure regulation. When the diaphragm is compromised, those demands can expose problems that are often misunderstood or misdiagnosed.

This article explores the relationship between hiatus hernias, core pressure, and training, and explains why certain approaches to core strength and conditioning may unintentionally worsen symptoms.

What Is a Hiatus Hernia?

A hiatus hernia occurs when part of the stomach moves upward through the diaphragm via the oesophageal hiatus — the opening that allows the oesophagus to pass from the chest into the abdomen.

Small hiatus hernias may cause minimal symptoms. Larger hernias, particularly those where a substantial portion of the stomach sits in the chest, create a mechanical problem rather than just a chemical (acid) one.

When this happens, several critical structures are affected simultaneously:

• The diaphragm

• The lungs

• The heart

• The oesophagus

• The vagus nerve

Any disruption to this system can alter breathing, pressure regulation, and nervous system balance.

The Diaphragm: More Than a Breathing Muscle

The diaphragm acts as a dynamic pressure regulator between two very different environments:

• The chest cavity (negative pressure)

• The abdominal cavity (positive pressure)

In healthy movement:

• The diaphragm descends on inhalation

• Abdominal pressure rises and falls rhythmically

• The stomach remains supported below the diaphragm

With a hiatus hernia:

• Diaphragmatic descent is restricted

• Pressure regulation becomes inefficient

• The stomach is exposed to thoracic pressure

• Breathing mechanics become compensatory rather than efficient

This has direct consequences for exercise and recovery.

Core Training and Intra-Abdominal Pressure

Modern training often emphasises:

• Constant core engagement

• Abdominal bracing

• Maintaining tension under load

• Breath control during lifting and running

While these strategies have a place, they also increase intra-abdominal pressure.

In someone with a compromised diaphragm, repeated or prolonged pressure increases can:

• Push the stomach further into the chest

• Increase strain around the oesophageal hiatus

• Worsen reflux, nausea, and chest pressure

• Trigger breathlessness and nervous system stress responses

Core strength is not the issue — pressure without mobility and diaphragmatic excursion is.

It’s important to understand that core strength itself isn’t the problem. Many people dealing with a hiatus hernia are actually very strong through their core. The issue comes when training focuses on constant tightening, bracing, or holding tension, without allowing the diaphragm to move freely.

The diaphragm needs to drop down when you breathe in and relax back up when you breathe out. If it can’t do that properly, pressure builds with nowhere to go. Instead of being absorbed and managed by the abdomen, that pressure is pushed upward toward the chest, right through the opening in the diaphragm.

Over time, this turns strength into a problem rather than a solution — not because the core is weak, but because it’s too tight and not moving the way it should.

How Hiatus Hernias Can Affect Training Performance

People training with a significant hiatus hernia may experience:

• Breathlessness at relatively low heart rates

• Poor tolerance to higher intensity training zones

• Chest tightness or pressure during exertion

• Palpitations or awareness of heartbeat

• Anxiety or adrenaline surges during or after exercise

• Delayed recovery following sessions

These responses are often mistaken for poor fitness or psychological anxiety, when they may be mechanically driven autonomic reactions.

The Nervous System Connection

Restricted breathing and altered pressure signals can confuse the brain’s threat-detection systems. When the brain interprets breathing restriction or pressure changes as a danger to oxygen delivery, it responds automatically with sympathetic activation.

This can lead to:

• Adrenaline release

• Elevated heart rate and blood pressure

• Panic-like sensations without a mental trigger

• Sleep disruption and poor recovery

In these cases, anxiety is not a mindset problem — it is a physiological response.

Can Training Make a Hiatus Hernia Worse?

A hiatus hernia is not caused by one specific exercise system. However, certain patterns can exacerbate an existing vulnerability over time, including:

• Chronic abdominal bracing

• Limited diaphragmatic movement

• High training volume under sustained pressure

• Reduced thoracic mobility

• Breath holding during effort

In my own experience, prolonged exposure to aggressive pressure-focused training without adequate emphasis on diaphragmatic movement and decompression may have contributed to my hernia becoming larger and more symptomatic.

This is not about blame — it is about understanding load, context, and adaptation.

Smarter Training With a Hiatus Hernia

Training with a hiatus hernia should prioritise:

• Restoring diaphragmatic movement

• Reducing unnecessary core bracing

• Managing intra-abdominal pressure intelligently

• Avoiding excessive breath holding

• Gradual exposure to load

• Adequate recovery for the nervous system

In some cases, medical or surgical intervention may be required to restore normal mechanics before training can progress safely.

Final Thoughts

A hiatus hernia is not just a digestive condition — it is a pressure, breathing, and nervous system issue that can profoundly affect training and recovery.

If exercise consistently leads to breathlessness, anxiety, chest tightness, or poor recovery, it may be worth looking beyond fitness metrics and considering whether mechanical pressure regulation is the limiting factor.

Sometimes the body is not weak or unfit — it is protecting itself from a system under strain.