gtoulpost3During vigorous physical activity, either indoors anaerobic at the gym, or outdoors aerobic, specific biochemical and hormonal evaluations are distorted.
Contractile muscles undergo rupture; in other words, muscle fibers are torn and myoblobin is released into the blood stream.
This protein carries oxygen to skeletal muscles, in similar way hemoglobin does to the rest of tissues. Myoglobin is a nephrotoxic substance to renal glomeruli, thus serum creatinine (CRE) is elevated.
Creatine kinase (CPK) enzyme increases up to ten fold.
Potassium (K) the main intracellular element is released in the bloodstream.
When its concentration reaches high levels, myocardium undergoes arrythmia, such as atrial fibrillation and ventricular tachycardia.
Striated muscle rupture equals to cellular death, therefore lactate dehydrogenase (LDH) elevates too.
Dehydration will lead to a higher osmolality of plasma.
In other words, plasma gets more concentrated and serum urea (BUN) elevates.
White blood cells initially increase, since exercise is a form of inflammatory process.
However, when overtraining occurs, the antiflammatory hormone cortisol is released from adrenal glands. Cortisolemia is linked with an increase of C-reactive protein (CRP), an acute inflammatory marker.
Chronic mental and physical stress, such as in marathon, triathlon and cycling, will eventually lead to a cortisol crush, due to adrenal fatigue and insufficiency.
During that time the absolute number of leukocytes is lowered and so does immune response.
Muscle degradation and catabolism will lead to drop of serum albumen and immunoglobulin levels IgA,IgD,IgG,IgM.
Chronic cortisolemia is associated to hypogonadism and low LH/TT.
Moreover, SHBG increases and FT goes down.
This is why chronic fatigue syndrome is combined to a loss in libido.
Electrolytes are lost through sweating, so Na, Cl, Mg, Ca will be remarkably low.
The hypocalcemia and hypomagnesemia will cost in muscle spasms, known as cramps.
Considering the fact that striated muscles, myocardium and liver posses common receptors for transaminases, its is obvious that Alanine transaminase (ALT) and Aspartic transaminase (AST) will be increased.
In order to differentiate from Acute Myocardial Infarction (AMI), we should evaluate the troponin protein that increases within 24 hours of heart attack.
In order to differentiate from potential liver disease, we should evaluate the cholestatic enzymes Gama glutamino transferase (γGT) and Alkaline phosphatase (ALP).
Lactic acid concentration is also found remarkably high.
Serum glucose (GLU) initially drops.
Soon after hepatic and muscle glycogen stores get depleted, neoglycogenesis through glucagon and cortisol will restore serum glucose.
In this time period, free fatty acids start to elevate in serum, due to beta oxidation of adipose tissue.
Lactic acid concentration elevates, leading to metabolic acidosis, where blood pH lowers and reaches 7.35.
Lungs hyperventilate in order to eliminate carbon dioxide.
Through hypocapnia, blood pH becomes alkalized.
Hypomagnesaemia and hypocalcaemia will lead to muscle spasms, the so called cramps.

In conclusion, strenous exercise is characterized as an acute metabolic episode.
In cellular level, endorphins drop, leading to moodiness; while cytokines are increased, leading to joint pains.
In urine microscopic evaluation, we observe microscopic hematuria and traces of cylinders.

LABORATORY ASSESSMENT DURING PHYSICAL STRESS

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