What Is Pulmonary Volume? | Sai Hospital, Haldwani

Breathing may feel automatic, but behind every breath is a precise measurement of how much air your lungs can hold, move, and exchange. Doctors often refer to this using the term pulmonary volume. Patients usually encounter it during lung function tests, asthma or COPD evaluation, pre-surgical fitness checks, or chronic breathlessness assessment.

At Sai Hospital, Haldwani, pulmonary volume measurements are an important part of diagnosing and managing lung and respiratory disorders. This article explains in clear, simple language what pulmonary volume is, its types, why it matters, and when it is tested.

What Is Pulmonary Volume?

Pulmonary volume refers to the amount of air present in the lungs during different phases of breathing. It describes how much air you can inhale, exhale, or retain in your lungs under various conditions.

In simple terms:
Pulmonary volume tells doctors how well your lungs can hold and move air.

These volumes reflect lung capacity, airway health, and breathing efficiency.

Why Is Pulmonary Volume Important?

Pulmonary volume helps doctors:

• Assess lung health
• Diagnose respiratory diseases
• Measure the severity of conditions like asthma or COPD
• Monitor disease progression
• Evaluate fitness before surgery
• Plan respiratory therapy

Abnormal pulmonary volumes may indicate obstructive, restrictive, or neuromuscular lung problems.

Main Types of Pulmonary Volumes

There are four basic pulmonary volumes, each representing a specific aspect of breathing.

Tidal Volume (TV)

Definition:
The amount of air inhaled or exhaled during normal, relaxed breathing.

• Average adult value: ~500 mL
• This is the air you breathe in and out at rest.

Clinical relevance:
Low tidal volume may be seen in lung disease, chest pain, or weak respiratory muscles.

Inspiratory Reserve Volume (IRV)

Definition:
The extra air you can inhale after taking a normal breath in.

• Helps measure how deeply you can breathe in.

Clinical relevance:
Reduced in restrictive lung diseases like pulmonary fibrosis.

Expiratory Reserve Volume (ERV)

Definition:
The extra air you can force out after a normal breath out.

Clinical relevance:
Reduced in obesity, COPD, and abdominal pressure conditions.

Residual Volume (RV)

Definition:
The amount of air remaining in the lungs after maximum exhalation.

• Lungs never empty completely.

Clinical relevance:
Increased residual volume is common in COPD and emphysema due to air trapping.

Pulmonary Capacities (Combination of Volumes)

Pulmonary capacities are formed by combining two or more pulmonary volumes.

Inspiratory Capacity (IC)

TV + IRV
Amount of air you can inhale after a normal exhalation.

Functional Residual Capacity (FRC)

ERV + RV
Air remains in the lungs after normal breathing out.

Important for maintaining oxygen levels between breaths.

Vital Capacity (VC)

IRV + TV + ERV
The maximum amount of air you can exhale after maximum inhalation.

A key indicator of lung strength.

Total Lung Capacity (TLC)

VC + RV
The total amount of air lungs can hold when fully inflated.

How Is Pulmonary Volume Measured?

At Sai Hospital, Haldwani, pulmonary volumes are measured using Pulmonary Function Tests (PFTs).

Common Tests Include:

1. Spirometry

Measures:

• Tidal volume
  
• Vital capacity
  
• Airflow rates
  

It is the most common and simple test.

2. Body Plethysmography

Measures:

• Residual volume
  
• Total lung capacity
  

Useful for detecting air trapping.

3. Gas Dilution Tests

Used when plethysmography is not available.

These tests are painless, non-invasive, and usually take 20–30 minutes.

Conditions That Affect Pulmonary Volume

Pulmonary volume changes depending on the type of lung condition.

Obstructive Lung Diseases

Examples:

• Asthma
• COPD
• Chronic bronchitis
• Emphysema

Typical changes:

• Increased residual volume
• Increased total lung capacity
• Air trapping

Restrictive Lung Diseases

Examples:

• Pulmonary fibrosis
• Interstitial lung disease
• Chest wall deformities
• Neuromuscular disorders

Typical changes:

• Reduced lung volumes
• Reduced vital capacity
• Normal or low residual volume

Neuromuscular Disorders

Weak respiratory muscles reduce inspiratory and expiratory volumes.

Obesity

Limits chest expansion and reduces expiratory reserve volume.

Symptoms That May Indicate Abnormal Pulmonary Volume

• Shortness of breath
• Difficulty taking deep breaths
• Chest tightness
• Reduced exercise tolerance
• Fatigue
• Frequent respiratory infections

If these symptoms persist, lung function testing is recommended.

Can Pulmonary Volume Improve?

Yes – depending on the cause. Pulmonary volume may improve with:

• Bronchodilator therapy
• Steroids (in asthma)
• Pulmonary rehabilitation
• Breathing exercises
• Weight management
• Smoking cessation
• Treatment of the underlying disease

Regular follow-up helps track improvement.

Pulmonary Testing at Sai Hospital, Haldwani

Our respiratory services include:

• Complete Pulmonary Function Tests (PFTs)
• Asthma and COPD evaluation
• Pre-operative lung assessment
• Post-COVID lung evaluation
• Pulmonary rehabilitation guidance

Tests are performed under expert supervision with accurate reporting.

FAQs: What Is Pulmonary Volume?

1. Is pulmonary volume the same as lung capacity?
Pulmonary volumes are individual measurements; lung capacities are combinations of these volumes.

2. Can pulmonary volume be low even if lungs are normal?
Yes, in obesity, weak muscles, or poor effort during testing.

3. Does smoking affect pulmonary volume?
Yes. Smoking increases residual volume and damages lung elasticity.

4. Is pulmonary volume tested in asthma?
Yes. It helps assess severity and response to treatment.

5. Are pulmonary volume tests painful?
No. They are safe, painless, and non-invasive.

Conclusion

So, what is pulmonary volume?
It is a measure of how much air the lungs can hold and move during different phases of breathing. These measurements are essential for diagnosing, monitoring, and treating respiratory conditions.

At Sai Hospital, Haldwani, pulmonary volume testing helps our doctors understand lung function clearly and plan personalized treatment for each patient. If you’re experiencing breathlessness, chronic cough, or reduced stamina, a simple lung function test can provide valuable answers – and early care leads to better breathing and better health.