Sports

Creatine kinase (CK)

Primary indicator of acute muscle damage after intense exercise.

Blood lactate elevation

A sign of increased anaerobic glycolysis during exercise.

Haematocrit

Most influenced by plasma volume expansion in endurance athletes.

Blood glucose after prolonged endurance exercise

Typically decreases if carbohydrate intake is insufficient.

Chronic low ferritin

Most commonly caused by haemolysis and sweat losses in athletes.

Low blood value in overtraining syndrome

Testosterone is likely to be low in an endurance athlete.

Creatine kinase post-exercise peak time

Peaks approximately 24–72 hours after exercise.

Blood sodium in dehydration

Is likely to be high.

Hormone rising during high-intensity exercise

Glucagon rises most in blood to maintain glucose supply.

Amino acid assessed for central fatigue

Tryptophan is often measured in blood.

Low blood urea nitrogen (BUN) indication

May indicate low protein intake.

Indicator of hydration status post-exercise

Plasma osmolality is a reliable marker.

Common electrolyte disturbance in ultra-endurance events

Hyponatraemia occurs with excessive water intake.

Free fatty acids in blood during prolonged exercise

Increase as glycogen depletes.

Sudden drop in blood haemoglobin post-high-altitude training

May be due to plasma volume expansion.

Vitamin status checked in low haemoglobin but normal ferritin

Folate is often checked.

Post-exercise blood lactate change in HIIT

Typically causes higher lactate levels compared to steady-state cardio.

Chronic muscle protein breakdown marker

Blood urea nitrogen is indicative of this condition.

Mineral impairing muscle contraction

Low magnesium can impair muscle contraction and endurance performance.

Blood marker increasing after glycogen-depleting exercise

Urea increases as a by-product of amino acid metabolism for gluconeogenesis.