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When Is It More Than Just Stress? Health Clues You Can Find in Your Blood

PBTT

Private Blood Tests Team

Clinical Team

29 Dec 202510 min read

We live in stressful times. Work pressures, financial concerns, family responsibilities, and the constant demands of modern life leave many people feeling perpetually exhausted, anxious, or simply not themselves. When you mention these feelings to friends or colleagues, the response is often the same: "It's just stress."

But what if it is not just stress? What if these symptoms are your body's way of signalling an underlying health issue that needs attention? Blood tests can reveal whether your symptoms have a physical cause that goes beyond everyday stress — and that knowledge can be life-changing.

The Problem with Dismissing Symptoms as "Just Stress"

Stress is real and can certainly cause physical symptoms. However, automatically attributing symptoms to stress is problematic for several reasons:

  • Medical conditions can mimic stress symptoms — Many treatable conditions cause fatigue, anxiety, and low mood
  • Stress and illness can coexist — You may be stressed AND have an underlying condition
  • Delay in diagnosis — Dismissing symptoms delays treatment for conditions that worsen over time
  • Self-blame — Attributing symptoms to stress can make you feel your suffering is somehow your fault
  • The truth is that many common medical conditions present with symptoms remarkably similar to chronic stress.

    Thyroid Disorders: The Great Mimicker

    Thyroid dysfunction is one of the most common causes of symptoms mistaken for stress, particularly in women.

    ### Hypothyroidism (Underactive Thyroid)

    Symptoms that overlap with stress:

  • Fatigue and low energy
  • Difficulty concentrating
  • Low mood and depression
  • Weight gain despite normal eating
  • Feeling cold
  • Sleep disturbances
  • ### Hyperthyroidism (Overactive Thyroid)

    Symptoms that overlap with anxiety:

  • Racing heart and palpitations
  • Anxiety and nervousness
  • Difficulty sleeping
  • Irritability
  • Trembling hands
  • Weight loss despite good appetite
  • Thyroid disorders are extremely common and highly treatable. For detailed information, read our guide to private blood tests for thyroid problems.

    Blood tests: TSH, Free T4, Free T3, thyroid antibodies.

    Anaemia and Iron Deficiency

    Iron deficiency is the most common nutritional deficiency worldwide and a frequent cause of persistent fatigue.

    Symptoms often attributed to stress:

  • Profound tiredness
  • Difficulty concentrating
  • Feeling weak
  • Breathlessness with minimal exertion
  • Dizziness
  • Low mood
  • Women of reproductive age are particularly susceptible due to menstrual blood loss. For more on fatigue investigation, read our article on why you should not ignore tiredness.

    Blood tests: Full blood count, serum iron, ferritin, transferrin saturation.

    Vitamin B12 Deficiency

    Vitamin B12 deficiency develops slowly and can cause debilitating symptoms that are easily mistaken for stress or depression.

    Symptoms often attributed to stress:

  • Fatigue
  • Memory problems and "brain fog"
  • Depression and mood changes
  • Difficulty concentrating
  • Numbness or tingling
  • Balance problems
  • Who is at risk:

  • Vegetarians and vegans
  • Older adults
  • Those with digestive conditions
  • People taking certain medications
  • Blood tests: Vitamin B12, methylmalonic acid (for borderline cases).

    Vitamin D Deficiency

    Vitamin D deficiency is extremely common in the United Kingdom and can significantly affect energy and mood.

    Symptoms often attributed to stress:

  • Fatigue
  • Low mood
  • Muscle weakness
  • General feeling of being unwell
  • Blood tests: 25-hydroxyvitamin D.

    Blood Sugar Problems

    Both diabetes and prediabetes can cause symptoms that mimic chronic stress.

    Symptoms often attributed to stress:

  • Fatigue, especially after meals
  • Difficulty concentrating
  • Irritability
  • Energy crashes
  • Increased thirst
  • For detailed information, read our guide to understanding the A1C blood test.

    Blood tests: Fasting glucose, HbA1c, fasting insulin.

    Inflammation

    Chronic low-grade inflammation can cause persistent fatigue and malaise.

    Symptoms often attributed to stress:

  • Fatigue
  • General aches and pains
  • Brain fog
  • Low mood
  • Inflammation can result from various causes including autoimmune conditions, chronic infections, or lifestyle factors. Learn more in our overview of the C-reactive protein test.

    Blood tests: CRP, ESR.

    Hormone Imbalances

    Beyond thyroid hormones, other hormonal imbalances can cause stress-like symptoms.

    ### Cortisol Dysregulation

    Ironically, chronic stress can dysregulate cortisol, which then perpetuates symptoms. Learn more in our article on the link between stress, cortisol, and your blood test results.

    ### Sex Hormone Imbalances

    Low testosterone (in men), oestrogen fluctuations, and other hormonal changes can cause:

  • Fatigue
  • Mood changes
  • Reduced motivation
  • Sleep disturbances
  • For more information, read our article on hormone imbalance symptoms you should not ignore.

    When Should You Get Tested?

    Consider blood tests if:

  • Your symptoms have persisted for several weeks
  • Rest and stress reduction have not helped
  • Symptoms are affecting your daily life
  • You have risk factors for specific conditions
  • Your symptoms are worsening
  • You want to rule out physical causes
  • A Comprehensive Approach

    Rather than testing for individual conditions, a comprehensive panel can efficiently screen for multiple causes at once:

  • Full blood count
  • Thyroid function (TSH, Free T4)
  • Iron studies and ferritin
  • Vitamin B12 and folate
  • Vitamin D
  • Fasting glucose and HbA1c
  • Liver and kidney function
  • Inflammatory markers (CRP)
  • For details on comprehensive testing, read our guide to what's included in a comprehensive health check.

    The Power of Knowing

    Blood test results can be transformative:

  • If a condition is found: Treatment can begin, often with dramatic improvement in symptoms
  • If results are normal: You can confidently address stress through appropriate means, knowing nothing physical is being missed
  • Either way, you gain valuable information about your health.

    Health Testing in London

    At Private Blood Tests London, we offer comprehensive health panels at our CQC-registered clinic in South Kensington. Our tests can reveal whether your symptoms have an underlying physical cause or whether stress management should be your primary focus.

    Explore our [thyroid function tests](/thyroid-test), [full blood count](/full-blood-count-test), and [comprehensive health screening packages](/health-screening).

    Stop wondering whether it is "just stress." Get answers. Book your blood test today.

    Ready to Book Your Test?

    Visit our CQC-registered clinic in South Kensington for professional blood testing services.