Medichecks Blood Testing For Better Sports And Athletic Performance 🔬💉🏋️‍♀️💪

This article is evidence-based, verified by Dr. Kiran Iqbal, MD, B.Sc

December Update: The results will be at the lab in the next few weeks and our 3-month study will come to an end. Our final analysis will look at all the things that have changed and improved during that time – stay tuned!

September Update: We’re excited to announce that we’ll be conducting our case study on optimizing Evander Armstrong’s blood panel. We’ll ask him to use the methods we’ve detailed in our blogs and track his progress with Medichecks. We have been using Medichecks for years before we approached them as an affiliate because of their fast results and affordability. They also provide an analysis from a qualified medical professional and use labs that meet the same clinical excellence demands of the NHS.

Biomedical data and athletics go hand in hand. In addition to following a good training program; being prepared for competition means having the right nutrition, a good sleep (related article), and using appropriate supplementation (related article) to contribute to your overall performance. If any of these factors are out of line, it could mean the difference between realizing your goals and not. 

To gauge these essential aspects there are a plethora of useful apps and tools available at one’s disposal. However, there is one method that is often underused in many fields of sports training, and that is using blood tests to track an athlete’s health and fitness. Blood work for sports performance can be used to determine the number of other factors and metrics that consistently and may even chronically affect your performance. 

Muscle and Endurance

If an athlete has a certain weight or muscle mass goal to achieve, following a nutritionist’s meal plan makes sense. They make sure that you have the right number of calories, the optimal ratio of macro-nutrients as well as other dietary requirements. In practical settings and training cycles, the nutritionist can get feedback from the athlete and their coaches regarding their energy levels and output and make adjustments when necessary.  

However, there are some limitations to this approach. Feedback may be biased and subjective as it relates to the athlete’s motivation since it can depend on unrealistic targets within specific time frames.  

Everybody is unique.  

Calcium is Key

The internal workings of all our organ systems may not always function how we want them to. Endurance athletes often need unique diets. For example, adult athletes need about 700 mg of calcium as part of their recommended daily allowance (RDA) (Source). Two long-distance runners may have different dietary requirements for calcium alone. They may have different food preferences or present with slight immune responses to dairy. Calcium absorption is inhibited by some naturally occurring plant chemicals: oxalate and phytate.  

Oxalate is found in foods like purslane, spinach, and tea; eating these in high amounts can inhibit calcium absorption (Source). Oxalates have also been found to inhibit iron and magnesium absorption. Although this may not be harmful for the average population, athletes with high energy requirements and mineral losses through sweat will benefit from monitoring their levels.  

Phytate is another unwanted mineral blocker, inhibiting the absorption of calcium, iron, and zinc (Source). This anti-nutrient is found in common plant-based protein sources like nuts, legumes, and kidney beans. However, phytates can be removed through methods such as soaking, fermenting and mixing with the enzyme, phytase, which is something humans naturally lack in their digestive tract. Plant-based diets may appear less than ideal on the surface (Source). However, through the athlete’s and nutritionist’s due diligence, there are plausible methods of mitigating the following health risks (Source)

For the Bones

Failing to meet one’s dietary calcium intake requirements can increase the likelihood of developing osteopenia (Source). Osteopenia is below average bone mineral density that isn’t severe enough to be classed as osteoporosis; for endurance athletes, this condition can be exacerbated through mineral losses through sweat and insufficient calorie intake (Source). Osteopenia increases the risk of stress fractures if it is left untreated and allowed to develop into osteoporosis.




Osteopenia, less than average bone mineral density increases the risk of stress fractures. Image from
Osteopenia, less than average bone mineral density increases the risk of stress fractures. Image from


Osteopenia, less than average bone mineral density increases the risk of stress fractures. Image from


While someone may feel fine, they may still be experiencing sub-optimal performance during their events. Many deficiencies can hide in plain sight. They often may appear as tiredness and general fatigue, or even manifest as lack of motivation. Chronic mineral deficiency may even cause an athlete to not recognize that they are tired because of a lack of proper nutrition, as they may have acclimated to those feelings. Blood testing allows anyone to see exactly what their body must work with, and more importantly what it doesn’t.  

It is important to note that blood levels of calcium do not represent the body’s total amount, signs and symptoms of deficiency will need to be examined by a qualified professional. 

Vitamin D deficiency can cause numerous problems in athletes, stunting the rate intestines absorb calcium from the food. According to recent research, below 12.5 ng/mL of Vitamin D in your blood may indicate a deficiency (Source). The expected range of a healthy individual seems to be between 20 and 60 ng/mL. However, people with active careers or anyone with a higher chance of bones breaking should likely have above 20 ng/mL. High levels of vitamin D above the healthy amount can become toxic in the bloodstream. 

While the ideal levels of vitamin D are often debated in the medical community, monitoring levels of this essential vitamin can help track patterns (Source)

Watch the video below for Dr. Rhonda Patrick’s detailed video about the importance of vitamin D

Another essential mineral that can especially affect the performance of an athlete is magnesium. Magnesium is critical for brain function. It is also required for the normal functioning of muscles and the entire nervous system. Low levels of magnesium can lead to serious problems ranging from cramps and muscle twitches to increasing your risk of developing mental illnesses. The recommended healthy range of magnesium as a marker in the blood is 1.5-2.5 mEq/L; these levels are tightly controlled by the kidneys and often urine magnesium levels are tested as part of a physician’s investigations.

Hypermagnesemia is having too much magnesium in the blood, it can cause issues like dampened reflexes, a decline in muscle strength, and even confusion. This condition is rare but can occur when one supplements with large doses. Although, like blood calcium tests, they do not represent the body’s whole magnesium stores; regular blood tests for athletes can help them determine how they need to stay in the healthy ranges (Source).  

Low levels of magnesium can also make vitamin D less effective, unused and potentially unsafe (Source). Correcting our magnesium intake can also mean that we need less vitamin D. This can make things a bit confusing but no less noteworthy as athletes should strive for efficiency in their training programs.  

Minimal effective intervention. Minimal effective change. Minimal effective dose.

In some forms of testing, it can be difficult to determine what’s missing. With well-performed blood testing, it is clear which levels are below their normal range. Once identified, this can often be rectified with affordable and simple dietary supplements. While in some respects we are in the early stages of genetic and blood marker research, it usually is being better safe than sorry by collecting more of an individual athlete’s data. It helps create a much clearer portrait of someone’s overall health, even when the specifics are being debated.

Revealing More Than We Can Perceive

One of the other main benefits of blood work for sports performance is discovering information that one may have never found out before. Allergen (Source) tests can be run, discovering a potentially deadly genetic predisposition towards, for example, bee stings. These tests can also reveal certain harmless environmental antigens that may be working as allergens for the athletes without them even realizing it. Someone playing a game of football in a different environment than home may cause them, due to environmental pollutants or allergens, to perform in a sub-optimal state. In high levels of competition, even the little problems can mean the difference between first place and second. Other helpful information can show up on a blood panel too. Identifying certain diseases that may not have been discovered otherwise like certain STIs or immune system issues is another huge benefit. Regular blood tests also encourage athletes to follow competition rules enforced by WADA, IPF or equivalent organizations. Building good self-accountability helps make competitions fairer for everyone.  

Another benefit of testing athlete’s blood regularly is being able to determine when they have been over-training and may not even feel it. Over-training syndrome (Source) is one of the reported worst things that an athlete can go through. According to a research, article posted by sports health, the over-training syndrome is essentially an incorrect naturally occurring body response to high levels of exercise without proper rest and care. This often can lead to burnout in a career, rapid mood swings, and the degradation of multiple systems in the body. While as a clinical diagnosis this syndrome tends to be ignored, the clear signs on the body are demonstrated in empirical data.  

Blood testing athletes for bio-markers such as a complete blood count, erythrocyte sedimentation rate, C-reactive protein, iron studies, creatine kinase, and thyroid-stimulating hormone can demonstrate some of the key indicators in an over-training syndrome case (Source).

Inflammation (related article). We all know it, and athletes find it to be one of their worst enemies in making sure they perform the best possible. Inflammation is a response by the body that is meant to protect it from some harmful effect or substance, however, it can often get out of hand and become a problem on its own. Chronic inflammation cannot only hinder someone’s health directly; it can also contribute to other conditions like over-training syndrome as we just discussed. Regular blood testing can evaluate and monitor the levels of certain proteins in the body that tend to be good indicators for inflammation (Source). Chronic inflammation can also contribute to and even create new issues like heart problems. Heart disease is the number one cause of death in the United States, and across the globe, it remains a serious health pandemic. Regular testing can be used as a tool to fight chronic inflammation and avoid it before it begins.

Rest and Recovery

Hormones are the other main category of measurable statistics of health that regular blood testing can provide insight into. Certain hormones like cortisol have been shown to appear in higher frequencies among over-stressed people. While there are lots of reasons that it can occur, frequent and prolonged periods of exercise stress to a body can cause increased levels to appear. A healthy range of cortisol can even change depending on the time of day. The expected range should be around 10-20 mcg/dL in the morning, and 3-10 mcg/dL in the afternoon. Making sure an athlete maintains a healthy range can prevent a huge range of negative symptoms like high blood pressure, muscle weakness, dehydration, and general fatigue.    

A prolonged demonstration of an increase in the ratio between both cortisol and cortisone (another hormonal indicator) is often present in athletes who could use better recovery times between their periods of intense exercise. Any substantial increases or decreases in the healthy cortisone/cortisol ratio of around 0.113 to 0.494 can be used as a biomarker for too much physiological stress. Detecting both high and low levels of testosterone can also help establish a better understanding of an athlete’s performance, including looking at the ratio between testosterone and cortisol. Healthy ranges of testosterone to cortisol appear to lie within 0.36 to 0.43. Tracking this ratio can help determine if an athlete is exercising correctly. For example, not spending enough time on recovery can be shown by a decrease in the ratio by more than 30% (Source).  

High levels of testosterone may be a biomarker for some serious underlying problems beyond behaviour or nutrition. High levels can cause increased fluid retention, prostate swelling and breast enlargement, and even a worsening of sleep apnea! Low levels can be associated with not being able to train or muscle build with high efficiency. The healthy range varies between men and women. Men on average should have between 240-950 ng/dl of testosterone in their blood, and women should have between 8-60 ng/dl (Source). High or low ranges can result in both bad results from the same levels of training as before and even in contributing to both emotional burnout and overtraining syndrome.  

Another essential hormone that can be tracked by a simple blood test is progesterone. This hormone in high levels can be associated with pregnancy in females, and thyroid gland issues in men. Both conditions can affect athletic performance (of course). If low levels are detected in an athlete there may be an issue with how their body is using energy. This issue can be simple, like not having proper dietary nutrition, or it can be indicative of a greater problem that may be causing this suboptimal performance. Developing a complex panel of regular blood work will be able to tell even more information about the health of an athlete. In addition to that these tests can also be used to determine if a new nutritional diet is working better, or if a certain regime is more successful than others in showing good results both inside and out. 

Tracking Changes and Being Accountable

There are many benefits that regular blood testing can provide. While the science is new and developing in some respects that can be measured, being careful never hurt anyone. Prevention is the key to modern medicine. Being able to understand a person’s health as they go along their life allows for greater accuracy in the preventive measures taken. Not developing a disease or condition is always preferable than treating one after it has already begun. In the same line of thinking, maximizing performance when even the smallest difference could matter, is a goal for any athlete or trainer worth their salt.

Unfortunately, it’s becoming more difficult to make appointments with your GP, people often needing to wait around 2 weeks before a slot becomes available in the UK (Source). While this can be troublesome for patients with illnesses needing attention, it becomes absurd for those aiming to optimize their health and performance. These blood tests provide results via email to your private intranet. While they do not replace making an appointment with a GP, they do have a place for those of us aiming for the next level.  

Blood work for sports performance can provide those athletes with essential information and paint a clearer picture of their health. From creating better diet plans, tracking certain nutrients, watching inflammation and heart disease, tracking bio-markers of stress, and watching out for new disease or allergens, there are many reasons why good testing is important for anyone, especially athletes.