Training

Can blood tests help your running?

Jun 21, 2020

Blood tests for runners

Distance running or endurance sport increases the workload on the physiological systems of the body. This also places strain on the immune system. Blood tests could  provide insight as to why a runner may not be improving in their performance or struggling through races. If one tends to fatigue easily or struggles to recover between intense sessions, chances are that your bloods could provide some answers.

Blood is a connective tissue structure and there are 3 types of living cells in blood –  erythrocytes commonly known as red blood cells, white leukocytes commonly called white blood cells and thrombocytes referred to as platelets.

Erythrocytes transport oxygen to the rest of the body and carbon dioxide back to the lungs. Leukocytes protect the body against disease and foreign invaders while thrombocytes help to contain the loss of blood during bleeding by forming a blood clot. Monitoring the levels of the above in your blood can be highly beneficial for endurance runners. In addition to the general indicators, which I’ll discuss shortly, there are also specific benefits for men and women.

It would be beneficial for women to be aware of this due to menstruating. This awareness allows you to plan your workouts, prevent aneamic states and provides insights into when to increase your iron consumption. Low iron levels means that oxygen transportation to your muscles is compromised hence causing fatigue and lactic acid build up. The type of training can affect hormone regulation that cause women to miss their cycle, abnormal bleeding or improper cycles. Therefore its important for women’s health, especially the female runner to be aware of this and have routine tests done regularly to prevent conditions such as RED syndrome.

It is no secret that endurance sport affects a man’s libido but that doesn’t mean you have to choose between being your running club’s poster boy or a stallion in the bedroom.Running long distances is known to lower testosterone levels due to the rise in cortisol levels which increase with endurance training. Lower testosterone affects muscle recovery post training. There is safe and guided treatment for this to help the male runner get the best of both worlds.

Below are the common indicators to look out for when undergoing a blood test:

  • Ferritin levels and Haemoglobin – Indicator of fatigue, lack of energy and low iron.
  • HDL Cholestrol & Thyroid – Low HDL Cholestrol affects heart health and, as a result, circulation and blood vessels function. Thyroid levels are important to ensure adequate functioning of your thyroid gland.
  • Complete blood count – White blood cells are an indicator to immunity while red blood cells indicate oxygen carrying capacity
  • Chemistry composition – Includes minerals and electrolytes. This indicates possible dehydration, susceptibility to cramps and basis for recovery.

Other blood markers provide information on risk to bone injury or joint conditions. These results are important to runners so that they can make the necessary changes to lifestyle such as nutrition, supplements and improved health management. One can prevent injury and illness by being proactive. You are able to accomplish training goals, understand your body better and be able to feel when something is amiss. Also these indicators can help us provide strategies and treatment to improve performance. Remember to speak to a qualified professional if this is something you would like to pursue.

Sumeshen Moodley


Sumeshen Moodley is a qualified physiotherapist in Durban who has worked with numerous international sports teams and athletes. He is passionate about running and has a special interest in human movement and biomechanics to optimise athletic/sport performance. Find out more about Sumeshen Moodley here

More articles