Abstract
Introduction: Hemolysis and rhabdomyolysis may result from prolonged physical activity such as long distance running and marathon.
Aim: The aim of this study was to assess the extent of cell damages after 42 km and 180 km of running, and to elucidate possible mechanisms of the membrane damage. The aim of this study was also to examine the effect of a simple dietary supplementation of antioxidative substances such as vitamin E, selenium and zinc.
Method: A 41-year-old female schoolteacher ran continuously for 24 hours, achieving a total running distance of about 180 km. A group of well trained marathon athletes, 60 men and 10 women with a median age of 36 years, participated in the Beito Marathon in Norway. A smaller group of less trained people, 19 men and 4 women was also followed during the same marathon.
Results: The hemolysis associated with marathon involved the apparent release of less than 250 mg hemoglobin per liter into plasma, whereas the 180 km run appeared to induce at least 20 times more hemolysis. The maximum values of released muscle enzymes after 180 km (CK 20.000 U/l), were several orders of magnitude higher than after marathon (CK 416 U/l). Furthermore, the prolonged physical exercise evoked a substantial inflammatory response.
Discussion: Mechanical factors alone may cause cell damage, but we hypothesized a contributory role of cellular formation of free oxygen radicals. Moderate doses of vitamin E and selenium given to well trained marathon runners appeared to exert only negligible protective effects, either because the initiating membrane lesion is not directly related to oxidative stress, or because the training itself represented a much stronger antioxidant protection. However, the extensive membrane damages observed in the ultra marathon phase (42 to 182 km) may be accelerated by a collapse of endogenous antioxidants. Thus, although glutathione (GSH) peroxidase appears to operate adequately for several hours of exercise in well trained individuals, it is tempting to presume an ongoing GSH depletion in the 42-to-182 km phase.
Conclusion: Systematic training and a balanced diet prior to long distance running and marathon may protect the body from organ disturbances in marathoners and ultra marathoners.
Keywords: Cell membrane integrity, exhaustive exercise, free oxygen radicals, GSH peroxidase, glutathione, membrane lesions, oxidative stress, reactive oxygen species, selenium, vitamin E, zinc
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