Altered Analytics in Athletes

Altered Analytics in Athletes

We analyse the reasons for Altered Analytics in Athletes

Athletes, whether we speak of strength athletes, or endurance athletes, have a special idiosyncrasy and particularities that are sometimes reflected in the analysis as “alterations” that must be understood in order not to alarm unjustifiably

Many of you have gone to your doctor, have had a routine blood test and have obtained altered results in it.

“Sit down. You see, the results of the analysis have been altered”

You start worrying and your doctor starts asking questions: Do you take any drugs? Do you smoke, drink, any other drugs? Do you take anabolics? Any previous illness? Have you traveled to exotic areas?


You get a knot in your stomach. Loose laughter comes in… As loose as your sphincter at this time. “But how are my analysis coming out bad if I am an athlete and with the discipline of a Buddhist monk? 🤷 That is something that happens only to my neighbour, who is always in the bar!”

This is a very common situation in medical consultations and even more so when we talk about ATHLETES

Why can athletes present tests with altered parameters?

Sadly, this undue alarm often occurs for various reasons:

  • Most physicians do not know how exercise works in general and how particular types of exercise can influence an individual’s analytical profile.


However, they do know what diseases cause the elevation or alteration of certain parameters, which athletes can also present in their analytics, so they try to track down and blame one of these diseases without thinking that they could be faced with variations of normality in a rather “special” population.”

  • The majority of the population is sedentary and therefore professionals are not used to seeing this type of analysis often


This may be very sad, but it’s real. The normality values in analytics are established based on statistical parameters obtained through a population sample. These people who make up the sample are chosen at random.

What happened? Unfortunately, today, more than 60% of the population is sedentary. Therefore we can say with certainty that the normal values in most laboratories are established on the basis of sedentary people and not the sporting population. If you’re an athlete, you’re weird.
Face it

  • The average athlete is also not usually informed about how their parameters can vary due to the exercise performed.

This is a source of anxiety and major concern


In this post we will talk about several parameters that can be altered in athletes, explaining why they are altered and what they mean.

*Mind you, we always talk about sporty individuals who do NOT use AAS (Anabolic Androgenic Steroids). These can produce other very specific alterations of which we will speak in another post if you want

What parameters can be raised in my blood test if I am an athlete?


Transaminases, as the name suggests, are liver enzymes responsible for trans-amination, that is, to move amino groups from one side to another to synthesize and degrade non-essential amino acids. I remind everyone that amino acids are the constituents of proteins.

Among these enzymes we find the following:

  • ALT-GPT (Alanine Aminotransferase or glutamate-pyruvate transaminase, indifferently): is found in the cytosol of hepatocytes
  • AST-GOT (Aspartate aminotransferase or Glutamate-Pyruvate transaminase): is also found in muscles, brain, kidneys and erythrocytes.
  • GGT (Gamma glutamyl transpeptidase)
Other parameters directly related to liver are: LDH, Direct bilirubin, Albumin and coagulation parameters

These enzymes can be seen to be elevated in multiple liver pathologies, such as cirrhosis, non-alcoholic steatohepatitis, infectious hepatitis or anabolic use. In these cases, however, the TAs generally rise by more than a 500% above baseline.

The normal levels of ALT and AST in most laboratories are <24 U/L. For GGT we have a slightly wider range that extends up to 80 IU/L.


Why do they rise after exercise?

Transaminases are elevated in athletes on certain occasions (not always) because there are enzymes that are highly in demand due to the different processes that occur in the body as a response to the physical stress involved in exercise.

In short, we can specify the reasons:

  • Muscle damage

Remember that some transaminases are also found in skeletal muscle, such as GOT, so the muscle damage intrinsic to exercise (especially strength exercise) will invariably raise your blood concentration 1 .

For the uninitiated: the muscle is composed of cells (myocytes) that suffer small breaks with training. These breaks release part of what’s inside those myocytes. And part of what’s inside are some enzymes, like transaminases, that go into the bloodstream, so when the nurse or nurse collects your blood, it carries higher concentrations than the “normal” of these molecules
  • Increased catabolism and protein anabolism (increased need for transamination by muscle microbrectures, increased turnover of non-myofibrillar proteins and increased subsequent resynthesis in anabolic period)

The liver is the largest factory in your body and is there to detoxify you of any non-useful element (drugs, drugs), but also to facilitate the synthesis of essential proteins and other structures.

In this synthesis the transaminases are very active, because as we have said, they put and remove amino groups from the constituent bricks of proteins: amino acids
  • Increased consumption of protein

As you may well have noticed, it occurs more frequently in the sports population, either for the purposes of muscle gain or fat loss.

An adequate protein intake for an athlete (between 1 and 1.5 grams/kg weight), however, should not result in elevation of transaminases in most people

And what happens if you’re healthy, asymptomatic, no signs of another disease, but you have AST and ALT levels at 70?

So you’ve probably gotten a good leg training between chest and back recently (or even better, between quadriceps and hamstrings?), or you went to your Crossfit BOX yesterday.


Should we be alarmed?

No. However, it must be made clear that we speak of a clinical context FREE OF SYMPTOMS, in which we do not suspect any other illness that could raise the parameters which are discussed in this post. Unfortunately, the disease also occurs in athletes of all ages who take care of themselves.

So, if there are any additional symptoms, tell your doctor. Maybe they don’t know about protein shakes and deep squats, but hepatitis, drug ADRs or various familial syndromes

So what levels are acceptable and when should I be concerned?

For a useful idea: not more than a 200% increase of the upper limit of normality.


In short, if your transaminases are slightly above range and you do not suffer with another illness, it is probably a consequence of the exercise performed and/or the supplementation that you use, and is not something serious

For you to have a reference, in most serious liver diseases transaminases are raised between 500% and 1000% above the LSN, so values of 50-100 IU/L, which is most frequently found in adult athletes, in the proper clinical context, should not worry us


Creatinine is nothing more than a by-product, a metabolite of creatine, a substance that is generated by some organs such as the pancreas, liver or kidneys, very consistently, structurally similar to some amino acids and which clear the kidneys and are subsequently excreted in the urine.

Creatine is a vector of the molecule ATP, transporting it through the body for use by muscle myofibrils


Unlike creatine, which is a well-known muscle energy substrate, creatinine does not have an established function in the body, rather it is a waste product of creatine itself, which is extremely good for us to estimate renal function

Why can it be raised in athletes?

  • Because they correlate with lean mass

A 25-year-old person with 80 kgs lean mass will have higher creatinine levels (usually outside the limits of normal) than a 60 kgs grandfather with 35 kgs lean mass.

What are you talking about? It’s very simple: if creatinine is generated by creatine and the latter is found in the muscles, the more muscle, the more creatine and more creatinine. When measuring your renal clearance it will be higher in people with higher lean mass.

  • Creatine Supplementation

If you take this known supplement, as is normal, the levels of creatinine in urine will rise, since it is the direct metabolite of creatine that you use for an increased sports performance2.

Should I be worried?

If your doctor has reasonably ruled out other causes of chronic kidney disease and the levels are only slightly above the upper limit of normal it is probably because you are a person with greater muscle mass than average, or you supplement yourself with creatine. Next question…


Bilirubin is a product of the metabolism of Hemoglobin (Hb), which is the molecule that carries oxygen into red blood cells so that all cells in your body can breathe.

This BR is divided into indirect and direct, depending on whether it has been conjugated (transformed) in the liver or not.

Training strength

BR elevations in the context of athletes are frequent and may be due to:

  • Repeated micro-traumas, such as those that occur in cross-country races. The mechanism is very simple: micro-traumas break down red blood cells that release Hb to the blood, which is metabolized to Bilirubin, which appears elevated in the blood.
  • Very demanding strength training, for the same reason.
  • Crossfit type of training. The same.
  • Gilbert’s syndrome, a very common syndrome in young people with asymptomatic BR elevation in periods of physical or mental stress, such as a cold, a good workout or a demanding career.
Other causes of PATHOLOGICAL elevation of bilirubin are: cholecystitis, pancreatitis, biliary and pancreatic tumors, rare familial syndromes, primary sclerosing cholangitis, hemolytic anemia, acute hepatitis, etc. But don’t get dramatic, we’re talking about healthy people


It is the muscle enzyme par excellence: rises in any muscle damage by being inside the myocytes. Some good examples of CK elevation causes would be:

  • Cardiac surgery: not only found in skeletal muscle, but also cardiac muscle. Any other surgery where there is muscle damage will also raise levels of the enzyme.
  • Prostration and bedding. Lying on the ground for a long time (homeless, alcoholics, mental illness patients, in ICU, etc.)
  • Running a marathon or a half marathon
  • Hard leg training. I said hard, doing the splits once won’t cut it!
  • Rhabdomyolysis: when this elevation is accentuated well above normal limits, we speak of rhabdomyolysis, a very serious clinical condition that requires admission, urgent rehydration and monitoring of renal function.
There has been much talk about the risk of rhabdomyolysis in ultra-background sports and CrossFit. If the topic catches your eye we can write about it later 3

Uric Acid

The number one archenemy of parents and grandparents: uric acid. AU is nothing more than a sotic substance product of the degradation and catabolism of molecules called purines (adenine and guanine), a reaction carried out by the enzyme xanthine oxidase.

In high amounts and, in the context of a genetic susceptibility involving less clearance or increased uric acid production, they can accumulate in various parts of the body crystallizing and causing the well-known illness, gout.

In an athlete patient, intense activity can raise blood AU levels up to 20% 4

Intensive activity

The consumption of a high-protein diet well above the recommended consumption in athletes (which, I repeat, does not go beyond 1.5-1.8 grs/kg of weight) can also contribute to this elevation, asymptomatic or not, of AU in blood


  • It is inevitable that from time to time your doctor will alert you of analytical alterations that are related to sports practice. Physicians do not have training in physical activity and sport, just as we lack adequate training in non-clinical nutrition.
  • What you should do and are responsible to do, before assuming that a slight elevation of transaminases or CK is not pathological, is reasonably ruling out other clinical entities that may produce such analytical alterations. As I said before, unfortunately disease also affects athletes.
  • On the other hand, understand your doctor. We don’t want to make anyone miserable, we don’t want you to stop exercising, we want you to be healthy and strong. What we tell you is said with the best of our intentions and on the basis of the knowledge we have.
And finally, if you’re okay, you’re asymptomatic, there’s no sign of another disease, you’re on a vegetable-rich diet, you train frequently, and you’re happy, then slightly higher values of creatinine or CK slightly above the upper limit of normal should not make your life miserable!


  1. Pettersson J, Hindorf U, Persson P, Bengtsson T, Malmqvist U, Werkström V, et al. Muscular exercise can cause highly pathological liver function tests in healthy men. Br J Clin Pharmacol [Internet]. 2008 Feb [cited 2018 Jul 13];65(2):253–9.
  2. Kreider RB, Kalman DS, Antonio J, Ziegenfuss TN, Wildman R, Collins R, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr [Internet]. 2017 Dec 13 [cited 2017 Aug 21];14(1):18.
  3. Brancaccio P, Maffulli N, Limongelli FM. Creatine kinase monitoring in sport medicine. Br Med Bull [Internet]. 2007 Feb 6 [cited 2018 Jul 13];81–82(1):209–30.
  4. Kanďár R, Štramová X, Drábková P, Křenková J. A monitoring of allantoin, uric acid, and malondialdehyde levels in plasma and erythrocytes after ten minutes of running activity. Physiol Res [Internet]. 2014 [cited 2018 Jul 13];63(6):753–62.

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About Javier Colomer
Javier Colomer
"Knowledge Makes Stronger", Javier Colomer's motto, sets out his clearest statement of intentions expressing his knowledge and fitness experience.
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