Breathlessness in London – When You Need Early Heart Testing

Reviewed by Dr Lauren Holland • Marylebone Diagnostic Centre
Results within 24 – 42 hours. Westminster residents receive 20% off.

Breathlessness is a common concern among London patients and can appear during exercise, walking upstairs, rushing for the tube, or even at rest. Some people describe a tight chest, shallow breathing, reduced stamina or feeling “out of breath faster than usual.” While breathlessness is often linked to stress, low fitness levels or seasonal illness, it can also signal iron deficiency, thyroid imbalance, low vitamin levels, anaemia, blood sugar changes or early heart strain.

Clinically, we see many London patients who notice breathlessness in busy commutes or during routine daily activity. Early blood testing is the most effective way to investigate internal causes and identify whether the heart, lungs or circulation are involved. This guide explains why breathlessness happens, which symptoms require urgent attention, and the tests at Marylebone Diagnostic Centre that detect early heart problems, including NT-proBNP.

Why Am I Breathless?

Breathlessness can come from the muscles, blood, lungs, heart or metabolism.

Common causes include:

Heart-related causes

• Early heart strain
• Reduced heart pumping capacity
• Fluid retention
• High blood pressure
• Arrhythmia

Non-heart causes

• Iron deficiency
• Thyroid imbalance
• Low vitamin D or B12
• Poor fitness
• Stress or anxiety
• Viral infection
• Dehydration
• Blood sugar swings

Blood testing helps narrow down which system is responsible.

What Does Early Heart Strain Feel Like?

People describe:

• Breathlessness on small hills
• Needing to stop when walking
• Tight chest
• Fatigue after mild activity
• Light-headedness
• Ankle swelling
• Irregular heartbeat
• Feeling “unfit” suddenly
• Waking up breathless

These symptoms match early heart stress signals seen in London patients.

When Is Breathlessness Serious?

Seek urgent review if you experience:

• Sudden severe breathlessness
• Breathlessness at rest
• Chest pain
• Blue lips or fingers
• Coughing up blood
• Rapid heartbeat
• Confusion
• Breathlessness worsening over days

These symptoms require immediate assessment.

Risk Factors for Breathlessness in London

You may be more likely to get breathless if you:

• Have high stress
• Live a busy commuting lifestyle
• Have low vitamin D (common in the UK)
• Have anaemia
• Have thyroid imbalance
• Smoke or vape
• Drink alcohol frequently
• Have a high BMI
• Have a family history of heart issues
• Work long hours with poor sleep

These patterns are widespread in London.

Blood Tests That Reveal Causes of Breathlessness

At Marylebone Diagnostic Centre, several tests help identify the cause.

NT-proBNP (Heart Strain Marker)

This is one of the most reliable early indicators of heart stress.

Elevated levels may indicate:

• Early heart failure
• Strain on the heart muscle
• Fluid retention
• Reduced pumping efficiency

Best for patients with:

• Breathlessness
• Chest tightness
• Swelling of ankles
• Fatigue
• Reduced stamina

NT-proBNP is included in MDC’s premium Cardiac Profile (MLCP2).

Cardiac Profile

MDC’s early heart-health panel includes:

• NT-proBNP
• Cholesterol & lipids
• CRP (inflammation)
• Kidney & liver function
• Full Blood Count

Ideal for:

• Breathlessness
• Chest tightness
• Dizziness
• Fatigue on exertion
• Palpitations

Full Blood Count (FBC)

Checks for:

• Anaemia
• Infection
• Low haemoglobin

Low haemoglobin reduces oxygen delivery and causes breathlessness.

Ferritin (Iron Stores)

Low ferritin is a top cause of breathlessness in women.

Thyroid Panel

Thyroid imbalance affects heart rate, breathing and circulation.

Symptoms include:

• Breathlessness
• Palpitations
• Fatigue
• Anxiety-like symptoms
• Temperature sensitivity

Vitamin D & B12

Both deficiencies are linked to:

• Breathlessness
• Muscle weakness
• Poor exercise tolerance
• Fatigue
• Dizziness

HbA1c (Blood Sugar Stability)

Blood sugar swings may cause:

• Breathlessness
• Shakiness
• Fatigue

Electrolytes

Important for muscle function and heart rhythm.

Which MDC Profiles Should You Choose?

Cardiac Profile

Best for:

• Breathlessness
• Chest tightness
• Palpitations
• Exercise intolerance
• Ankle swelling

This profile includes NT-proBNP for early detection.

Wellness Profile

Ideal when symptoms are unclear or include fatigue or dizziness.

Vitamin & Mineral Profile

Useful when breathlessness relates to weakness or low energy.

Thyroid Profile

Important if breathlessness comes with anxiety, palpitations or fatigue.

FBC + Ferritin

Best for breathlessness caused by anaemia or low iron.

Table: Breathlessness Symptoms and Matching Tests

FAQs (People Also Ask)

Book Your Heart and Breathlessness Tests at Marylebone Diagnostic Centre

Marylebone Diagnostic Centre
73 Baker Street, London W1U 6RD
Tel: +44 7495 970109
Open Monday–Saturday, 08:00–16:00

Fast, private and confidential testing with results in 24–42 hours.
Westminster residents receive 20% off.

Quick Links

• Cardiac Profile
• HbA1c Test
• Full Lipid Panel
• Fatigue and Energy Profile
• Kidney Function Test
• Electrolytes Test
• Liver Function Test
• Thyroid Function Test
• Magnesium Test
• Full Blood Count
• Urinalysis & Culture
• Book an Appointment
• ECG Testing
• Wellness Profile
• Pancreatic Profile
• Advanced Sexual Health Panel
• STI Testing London

Read More

• NHS – Breathlessness (Dyspnoea)
• British Heart Foundation – Breathlessness and Heart Conditions
• NHS – Anaemia Overview
• British Thyroid Foundation – Thyroid Symptoms
• European Society of Cardiology – NT-proBNP Guidance