Blood Profiling for Athletes

When can blood profiling be useful?

While regular and consistent training will absolutely improve your performance, sometimes underlying health issues can affect how well you perform. One common example for runners is low iron levels (known as ferritin stores) which often lead to significant underperformance and even have an effect outside of the training and racing arena.

Blood testing or blood profiling is used by athletes at all levels to check for signs of poor recovery, nutritional deficits, or issues with underlying health.

Blood profiling is not a prerequisite for all athletes. When there is a continued problem with under-performance, that is not a direct result of poor training, getting a blood test can help identify the root cause.

What can I do to help address unexplained under-performance?

During periods of abnormal fatigue or under-performance in training / racing, one of the first ports of call to solve the issue is a blood test. Blood tests are typically used by GP’s, sports doctors or physicians to detect a variety of health problems so that they can be prevented or treated before getting worse.

What blood markers may be measured to investigate under-performance?

A full blood count entails many tests that are important to both general health and to sports performance. However, some of these markers are more important than others for endurance performance. These markers are outlined (but are not limited to) in the table below

What do these markers mean for an athlete?

Ferritin: This test measures how much iron there is stored in your liver (iron stores). If ferritin levels are low, it could mean that the liver is not producing enough red blood cells or that there is not enough iron available for them to produce more red blood cells. This may be due to anaemia or iron deficiency, which needs treatment with supplements or dietary changes. Low ferritin stores impact the body’s ability to produce red blood cells and result in excess fatigue, poor training and racing performance.  

Haemoglobin: Haemoglobin is the protein that carries oxygen in your blood. When you exercise, your body uses up more oxygen than usual and needs additional haemoglobin to help transport it throughout your body. If you do not have enough haemoglobin in your body or if it is not being used efficiently by your muscles, you may experience fatigue while exercising. There is a strong correlation between Ferritin stores and haemoglobin levels. Both tend to trend in the same direction.

Haematocrit: The amount of water in the blood affects how much blood there is per unit volume (the haematocrit). As a result, haematocrit can affect how efficiently oxygen is transported through the body when exercising. Similar to Haemoglobin, when haematocrit levels are low, it leads to low energy, fatigue and poor training or racing performance. This makes haematocrit another important marker of blood health in athletes.

Thyroid Function Tests: Thyroid hormone controls metabolism, so it is important to ensure your thyroid is working properly if you want to perform well during competition. A standard TSH test should always be performed first, followed by one or more additional tests depending on what the results reveal (TSI and fT4). Poor thyroid function has been linked to over-training but is more commonly triggered by genetics or a family history of the condition.

Vitamin D: A very common vitamin deficiency is in Vitamin D. The most common way to boost Vitamin D is by spending time outside and eating a well-balanced diet. High Vitamin D is associated with reduced injury rates and better performance. Athletes feeling excess fatigue, suffering recurring injuries or bone health problems, maybe prompted by a GP to have their Vitamin D levels checked.

White Cell Count: White blood cells play an important role in fighting infections and protecting your body from disease. When there are not enough white blood cells, an athlete may be at risk of getting sick more easily than someone with normal levels of white blood cells.

Neutrophils: Neutrophils are one particular type of white blood cell that helps fight infection and heal wounds. Athletes who have low neutrophil counts may be more susceptible to infections and injuries due to their weakened immune systems. The level of neutrophils often correlates with the athlete’s overall state of health and recovery.

How might I get a blood test?

If you or your coach have reason to suspect there may be an issue and require a blood profile, there are a number of options available.

The first and often most simple route is to contact your GP or physician. Explain the symptoms, your training history and the reason you feel that a test is required. The doctor will be able to advise if a test is warranted or not. They can also advise on options of where and how to get the test done.

There are several independent companies offering blood profiling, particularly for athletes. These blood profiles are often more detailed than a standard blood test and analyse additional markers to those commonly looked at via your GP. They come at a higher cost but, depending on your level of requirements, this may be a necessary spend.

Do I need to fast for the blood test?

When getting bloods taken, it is worth confirming with the test provider whether or not the bloods should be taken fasted or not. This can have a significant bearing on the outcome of some blood markers.

Do I need to adjust my training before the blood test?

Yes. It is worth adjusting training on the day of the test. Try to avoid hard or long sessions prior to the test. A hard training effort will leave you dehydrated, which directly impacts many of the important markers. The heavy session may also impact the results in other ways and prevent a valid comparison to previous or future tests.