Maraton och fria radikaler

[kalle_banan]

Jag såg på en föreläsning av Fredrik Paulún i veckan och han sa att det bildas mycket fria radikaler av maraton, såpass mycket att levern liknar en alkoholists lever efteråt.
Så hur mycket behöver man bry sig om det? Jag springer inte maraton, men enligt den logiken finns det en övre gräns för hur mycket man bör träna innan det blir skadligt (skadligt med hänseende till de fria radikalerna, andra faktorer kan bortses från för närvarande).

[King Grub]

Det kompenseras via ökad kapacitet att ta hand om fria radikaler. Långtidseffekten är oklar.

Prolonged exercise induces a marked response of oxidative stress biomarkers, which in part is compensated by serum ability to scavenge free radicals. Whether these changes have long-term negative effects in the organism needs further investigation.

http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2362.2007.01917.x

[kalle_banan]

Så om jag vill satsa på ett maraton gör jag rätt i att sakta men säkert öva upp min kropps förmåga att ta hand om de fria radikalerna och jag borde vara säker, men hur det fungerar i det långa loppet vet man inte?

[Eddie Vedder]

Moderate exercise is a healthy practice. However, exhaustive
exercise generates free radicals. This can be evidenced by increases
in lipid peroxidation, glutathione oxidation, and oxidative protein
damage. It is well known that activity of cytosolic enzymes in blood
plasma is increased after exhaustive exercise. Thismay be taken as a
sign of damage to muscle cells. The degree of oxidative stress and of
muscle damage does not depend on the absolute intensity of exercise
but on the degree of exhaustion of the person who performs exercise.
Training partially prevents free radical-formation in exhaustive
exercise. Treatment with antioxidants such as vitamins C or E
protects in part against free radical-mediated damage in exercise.
Xanthine oxidase is involved in free-radical formation in exercise
in humans and inhibition of this enzyme with allopurinol decreases
oxidative stress and muscle damage associated with exhaustive exercise.
Knowledge of the mechanism of free-radical formation in
exercise is important because it will be useful to prevent oxidative
stress and damage associated with exhaustive physical activity.

Free Radicals in Exhaustive Physical Exercise: Mechanism of Production, and Protection by Antioxidants. Life, 50: 271–277, 2000

Strenuous exercise increases oxygen consumption and causes disturbance of intracellular pro-oxidant–antioxidant homeostasis. The mitochondrial electron transport chain, polymorphoneutrophil, and xanthine oxidase have been identified as major sources of intracellular free radical generation during exercise. Reactive oxygen species pose a serious threat to the cellular antioxidant defense system, such as diminished reserve of antioxidant vitamins and glutathione, and increased tissue susceptibility to oxidative damage. However, enzymatic and nonenzymatic antioxidants have demonstrated great adaptation to acute and chronic exercise. The delicate balance between pro-oxidants and antioxidants suggests that supplementation of antioxidants may be desirable for physically active individuals under certain physiological conditions by providing a larger protective margin.

http://www.ebmonline.org/cgi/content/full/222/3/283

Antioxidants and Oxidative Stress in Exercise. Proceedings of the Society for Experimental Biology and Medicine 222:283-292 (1999)

EDIT: Jag är verkligen SJUKT långsam!*gah!*

[machine gun]

Så om jag vill satsa på ett maraton gör jag rätt i att sakta men säkert öva upp min kropps förmåga att ta hand om de fria radikalerna och jag borde vara säker, men hur det fungerar i det långa loppet vet man inte?

Det är ju en viss skillnad på att som motionär springa sådär ett marathon om året och att vara marathonlöpare på elitnivå också.