The Blood Tests Every Athlete Should Be Taking in 2026

A clear guide to the most important blood tests that help athletes track health, performance and recovery in 2026.

Key takeaways

• The right blood tests help athletes spot issues early and avoid training setbacks.
• Important markers include iron, vitamin D, thyroid function and overall health indicators.
• Regular testing supports safer training, better recovery and long term performance.

Athletes place their bodies under repeated physical stress, whether training for competitions or keeping up a heavy weekly schedule.

When performance dips, energy drops or recovery slows, there is usually a biological reason behind it.

Blood testing gives athletes a clear view of what is happening inside the body, helping them train safely and perform consistently.

This guide explains the most useful blood tests for athletes in 2026, how they support performance, and the signs that indicate it may be time to get tested.

Everything in here is based on safe, medical guidance, with no performance-enhancing claims.

Why Blood Testing Matters for Athletes in 2026

Training has become more structured and data-driven in recent years. Many athletes track sleep, heart rate and training load, yet overlook the internal markers that influence energy, recovery and injury risk.

Blood tests help identify issues such as low iron, low vitamin D, thyroid imbalance, inflammation or poor long term energy regulation.

These problems often show up as tiredness, slower progress or repeated illness, and can easily be mistaken for training fatigue.

A GP can use blood tests to check overall health, rule out underlying concerns and guide an athlete toward confident, safe training.

Core Blood Tests Every Athlete Should Consider

These tests offer the most useful insight into performance, recovery and general wellbeing.

Full Blood Count (FBC)

An FBC checks red blood cells, white blood cells and platelets. For athletes, it helps assess oxygen-carrying capacity, infection risk and overall resilience.

Low red blood cells or haemoglobin may show up as breathlessness, poor stamina or a drop in endurance. Low white cells can make you more prone to illness, which affects training consistency.

Iron Studies (Ferritin and Iron Levels)

Iron is one of the most important markers for athletic performance. Ferritin shows iron stores, which strongly influence energy, oxygen delivery and stamina.

Low ferritin is common in runners, cyclists, women and anyone with a high training volume. Symptoms often include heavy legs, breathlessness, slow recovery and reduced power output. Iron testing is one of the quickest ways to identify these issues.

Thyroid Function (TSH)

The thyroid helps regulate metabolism, energy and temperature control. Even small changes can affect training.

Low thyroid function can cause fatigue, slower recovery, weight changes and reduced performance. These symptoms often overlap with overtraining, which is why checking thyroid levels can be helpful.

Vitamin D Levels

Vitamin D supports bone health, muscle function and immune strength. In the UK, levels tend to fall in winter, making deficiency common.

Low vitamin D can increase injury risk and contribute to tiredness or muscle weakness. Regular testing helps athletes stay within a healthy range year-round.

Lipid Profile (Cholesterol)

Athletes often assume cholesterol is not relevant, but long term heart health is essential for training safely.

A simple lipid profile checks overall cardiovascular risk and ensures a training plan is supported by good health markers.

HbA1c (Blood Sugar Control)

This test shows how the body manages blood sugar over time.

Some athletes experience energy crashes, poor recovery or disrupted sleep linked to unstable glucose levels. HbA1c offers an early warning for any issues with long term energy regulation.

Additional Tests Athletes May Find Useful

These tests are often recommended when symptoms, training load or overall health suggest further insight is needed.

Inflammation Marker (CRP)

CRP helps show whether inflammation is affecting training.
Raised levels can appear with overuse injuries, illness or poor recovery. A normal result offers reassurance that the body is coping well with training.

Liver and Kidney Tests (LFT & U&E)

These tests support safe training by checking hydration status and organ function.
They are particularly useful for athletes using supplements, as well as those training in high volumes.

B12 and Folate

These vitamins support energy production and nerve function.
Low levels can cause fatigue, pins and needles and reduced endurance. Vegetarians and vegans may be more at risk.

How Often Should Athletes Get Blood Tests?

Blood testing frequency depends on training intensity and overall health, but many athletes benefit from testing every 3 to 6 months.

This allows enough time to see changes while still catching problems early.

More frequent testing may be useful when:

• starting a new training block
  
  

• recovering from injury or illness
  
  

• experiencing continued tiredness
  
  

• increasing training volume or intensity
  

Blood tests can highlight concerns early, helping athletes adjust training safely.

Signs You May Benefit from a Blood Test

You may find a blood test helpful if you notice any of the following:

• Ongoing fatigue or feeling unusually tired
  
  

• Slower recovery after normal sessions
  
  

• Drop in performance or motivation
  
  

• Recurrent colds or infections
  
  

• Muscle weakness or heavy legs
  
  

• Sleep changes
  
  

• Training feeling harder than expected
  

These symptoms have many possible causes, and blood testing helps determine whether there is a physical reason behind them.

Preparing for a Blood Test as an Athlete

Most blood tests require no complex preparation, but a few simple steps can help ensure accurate results:

• Stay well hydrated the day before
  
  

• Avoid intense training on the morning of your test
  
  

• Bring a record of any supplements you take
  
  

• Ask whether fasting is needed. Many tests do not require it, but it is always best to check
  

This small amount of preparation ensures clearer results and better interpretation.

When to See a GP Instead of Adjusting Training Yourself

Athletes sometimes assume tiredness or mood changes are “part of training”. In some cases, they are not.

You should speak to a GP if you experience:

• Chest discomfort or dizziness
  
  

• Fainting or near-fainting
  
  

• Unexplained weight loss or gain
  
  

• Severe tiredness not linked to training
  
  

• Persistent illness
  

These issues need medical assessment rather than training changes.

Final Thoughts and Ready Health Support

Blood tests give athletes a clearer understanding of their health and how their body responds to training.

They can highlight problems early, support safer performance and help guide long term wellbeing.

Ready Health offers private blood testing with GP-led interpretation, including full blood counts, thyroid checks, vitamin D levels, iron studies and other key markers that help athletes understand their health.

Same-week appointments are available at our Standish clinic, with clear and supportive medical guidance at every step.

If you want tailored insight into your health as an athlete, Ready Health can provide the tests and GP advice you need to train with confidence.

Frequently Asked Questions

What blood tests should athletes get regularly?
Most athletes benefit from tests such as a full blood count, ferritin and iron levels, vitamin D, thyroid function and blood sugar markers to monitor health, recovery and training tolerance.

How often should athletes have blood tests?
For most people training regularly, blood tests every 3 to 6 months are sufficient, with earlier testing recommended if symptoms such as fatigue, poor recovery or repeated illness appear.

Can blood tests explain fatigue or poor performance in athletes?
Yes. Blood tests can identify common underlying causes such as low iron, vitamin deficiencies, thyroid imbalance or inflammation that may affect energy, endurance and recovery.

Do athletes need a GP to review blood test results?
Yes. Blood tests should always be interpreted by a GP alongside symptoms and training load to ensure results are understood correctly and any next steps are appropriate.