Dizziness and Light-headedness in London – Causes & Blood Tests to Consider
Reviewed by Dr Lauren Holland • Marylebone Diagnostic Centre
Results within 24 – 42 hours. Westminster residents receive 20% off.
Dizziness and light-headedness are common reasons Londoners seek medical help. Many people describe a floating sensation, blurred vision, unsteadiness or a feeling that the room is moving. These symptoms can be linked to dehydration, stress, infection, low blood pressure or problems with the ears. However, persistent dizziness can also indicate anaemia, thyroid imbalance, vitamin deficiency, changes in blood sugar or signs of early heart strain.
Clinically, we see many patients who feel dizzy on the tube, during long workdays, or after standing up quickly. Blood testing is one of the fastest ways to understand the cause. This guide explains why dizziness happens, which symptoms need urgent review, and which tests at Marylebone Diagnostic Centre help identify the underlying issue.
What Causes Dizziness and Light-headedness?
Dizziness has many possible triggers. Common causes include:
- Low iron or ferritin
- Thyroid imbalance
- Low blood pressure
- Vitamin D or B12 deficiency
- Inner-ear problems
- Anxiety or stress
- Dehydration
- Low glucose
- Viral infection
- Heart strain
Londoners often experience dizziness during busy commutes, long hours, skipped meals or sudden stress.
Why Do I Feel Dizzy and Weak?
People often ask:
“Why does my body feel weak and tired all of a sudden?”
This may be caused by:
- Blood sugar drops
- Low iron
- Poor hydration
- Thyroid imbalance
- Viral infections
- Sudden changes in blood pressure
These symptoms are often reversible once the correct cause is identified.
When Is Dizziness Serious?
People search:
“How to know if dizziness is serious?”
Dizziness requires urgent attention if you:
- Faint
- Have chest pain
- Feel breathless
- Experience sudden headache
- Have weakness on one side
- Experience confusion
- Lose balance suddenly
- Notice irregular heartbeat
If your dizziness is persistent or worsening, blood tests help provide answers.
Risk Factors for Dizziness
You are more likely to experience dizziness if you:
- Have low iron
- Have thyroid disease
- Are dehydrated
- Drink caffeine or alcohol regularly
- Have irregular meals
- Work long shifts
- Have chronic stress
- Recently had a viral infection
- Take blood-pressure medication
- Have poor sleep
These risk factors often overlap in busy cities like London.
Types of Dizziness (The 3 Key Patterns)
People ask:
“What are the three types of fatigue?”
(similar logic applies to dizziness categories)
Clinically, dizziness presents in three patterns:
- Vertigo – spinning sensation
- Presyncope – feeling faint or lightheaded
- Disequilibrium – imbalance or unsteady walking
Blood tests help rule out internal medical causes.
What Blood Tests Can Reveal About Dizziness
At Marylebone Diagnostic Centre, the following tests help identify the cause:
Full Blood Count (FBC)
Rules out anaemia, infection and low haemoglobin.
When to test:
- pale skin
- shortness of breath
- dizziness on standing
- heavy menstrual cycles
Ferritin (Iron Stores)
Low ferritin is a leading cause of dizziness, especially in women.
Thyroid Panel
Thyroid imbalance affects heart rate, blood pressure, energy and balance.
Symptoms include:
- palpitations
- cold sensitivity
- hair loss
- sudden weakness
- anxiety episodes
Vitamin D & Vitamin B12
Low levels cause fatigue, muscle weakness, slow reactions and dizziness.
Vitamin B12 is essential for:
- nerve function
- balance
- concentration
- coordination
HbA1c (Blood Sugar Stability)
Low energy and light-headedness may be linked to glucose levels.
Consider this test if you:
- feel faint between meals
- crave sugar
- experience sudden energy crashes
Kidney & Liver Function
These tests identify causes of nausea, dizziness, confusion and weakness.
Electrolytes (Sodium, Potassium, Magnesium)
An imbalance affects hydration, heart rhythm and muscle control.
NT-proBNP (Heart Strain Marker)
Clinically important if dizziness is paired with:
- breathlessness
- exercise intolerance
- ankle swelling
- chest tightness
This test forms part of MDC’s Cardiac Profile (MLCP2) for early heart detection.
MDC Profiles Recommended for Dizziness
Marylebone Diagnostic Centre offers precise profiles linked to dizziness:
Wellness Profile
Includes:
- Full Blood Count
- Ferritin
- Vitamin D
- B12
- Kidney & Liver Function
- HbA1c
Ideal for general fatigue and weakness.
Thyroid Profile
Checks common causes of dizziness, slow metabolism and temperature sensitivity.
Cardiac Profile (MLCP2)
Includes NT-proBNP.
Recommended if dizziness is associated with breathlessness or palpitations.
Vitamin & Mineral Profile
Includes Vitamin D, B12, Folate, Magnesium and Zinc.
Useful when dizziness relates to nutritional deficiency.
Urine Analysis
Useful when dizziness is linked to dehydration or infection.
These profiles give a complete picture of internal health.
Table: Dizziness Symptoms and Related Tests
| Symptom | Possible Cause | Recommended Test |
| Lightheaded on standing | Low blood pressure, anaemia | FBC, Ferritin |
| Weakness & heaviness | Vitamin deficiency | Vitamin & Mineral Profile |
| Palpitations & dizziness | Heart strain | MLCP2 (Cardiac Profile) |
| Dizziness after meals | Glucose imbalance | HbA1c |
| Brain fog & unsteadiness | Low B12 | Vitamin B12 test |
| Dizziness with fatigue | Thyroid imbalance | Thyroid Panel |
Clinical Insight
“In London, we often see dizziness linked to low iron, thyroid imbalance or changes in blood sugar. A simple set of tests usually identifies the cause quickly.”
– Dr Lauren Holland
FAQs (People Also Ask)
Book Your Dizziness Panel 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
- Liver Function Test (LFT)
- General Health Profile
- Iron Studies / Iron Profile
- Fatigue and Energy Profile
- Advanced Wellness Profile
- Vitamin B12 Test
- Vitamin D Test
- Full Blood Count
- Thyroid Function Test
- Book an Appointment
- HbA1c (Diabetes Marker)
- Kidney Function Test
- Mineral Analysis
- Cardiac Profile
- Urine Analysis
Read More
- NHS – Fatigue: Causes, Symptoms and Treatment
- NHS – Vitamin D
- NHS – Anaemia
- British Thyroid Foundation – Fatigue and Thyroid
- Endocrine Society – Fatigue and Hormones
- NHS – Dizziness Causes and Treatment
- Mayo Clinic – Lightheadedness and Dizziness Overview
- NHS – Iron Deficiency Anaemia
- NHS – Thyroid Problems
