Intense exercise increases the generation of FREE RADICALS and LIPID PEROXIDATION resulting in cellular damage, which is reversible, but potentially leading to muscle injury. 

Aerobic training enhances antioxidant defenses, especially by increasing a particular enzyme, called superoxide dismutase (SOD). 
Often this is not enough to counter the excess of free radicals and signs of cellular damage begin to appear in the blood: increased transaminases (ALT, AST), alkaline phosphatase, lactic dehydrogenase (LDH), creatine kinase (CK), thiobarbituric acid (TBA). 
Even red blood cells undergo an important oxidative stress, which is also responsible of a reduction in the availability of iron. 

The more strenuous or prolonged the physical effort, the greater the increases in these markers (Br J Sports Med 1996, 30:122-124). 

Vitamin C, vitamin E, beta-carotene are able to limit these effects (Int J Sports Med 2000,21:369-374 ,  J Am Coll Nutr 2007,26:111-120) and their supplementation to the diet is recommended for those athletes engaged in intense efforts (J sports Med Phys Fitness 1997,37:235-239 , Sports Med 2000,29:73-83 ,  Pflugers Arch 2003 446:658-664). 

Dietary supplementation with FISH OIL (1600mg EPA + 800mg DHA per day for 6 weeks) can increase lean body mass, decrease fat mass and reduce salivary cortisol in healthy adults (J Int Soc Sports Nutrition 2010, 7: 31). 
EPA and DHA suppress the expression of lipogenic genes, limiting the synthesis of fats. 
They are also able to enhance the entry and oxidation of lipids in the mitochondria, an effect that is particularly pronounced in migratory birds as they prepare for the long non-stop flights by eating large amounts of EPA and DHA present in marine invertebrates for weeks several (J exp Biol 2006, 209:2686-2689). 

In a very interesting study, Nagahuedi et al (J exp Biol 2009, 212: 1106-1114) verified similar effects to those of migratory birds in sedentary quails fed with EPA and DHA, with increases in oxidative enzymes and the composition of membrane lipid in mitochondria. 

EPA and DHA are also able to improve the deformability of red blood cells, reducing the viscosity of blood (Atherosclerosis 1985, 55:267). 
Because fish oil promotes oxidative processes, its intake should be combined to adequate doses of vitamin E (200-600U/die) (Med Sci Sports Exercice 2000,32:601-607). 

SPIRULINA, a green algae that grows in salty and alkaline waters, is the best source of vegetable protein (65% of its weight), as well as particularly rich in beta-carotene (23000U/10g), Vitamin D (1200U/10g) and Vitamin B12 (20mcg/10g). 

10g of spirulina contain 10 mg of iron, bound to its blue pigment, the phycocyanine, which makes it more assimilable than that found in plants and even ferrous sulfate. 
Spirulina is particularly rich in chlorophyll (100mg/10g): the molecular structure of this green pigment is very similar to that of hemoglobin, with a central magnesium atom instead of iron. 
The chlorophyll molecule is split by the intestinal flora and it is likely that the fragments are used by the organism for the synthesis of hemoglobin : this fact, together with bio-available iron, could explain the effectiveness of spirulina in the contrast of anemia.