Lung (2003) 181:89–95 DOI: 10.1007/s00408-003-1009-y
Hematologic and Biochemical Laboratory Parameters Before and After a Marathon Race K. Spiropoulos and G. Trakada University Hospital of Patras Medical School, Department of Internal Medicine, Division of Pulmonology, Patras 26500, Greece
Abstract. Marathon racing is a strenuous exercise that has a profound effect on many laboratory parameters. Participants in marathon races may require abstinence of exercise and the performance of laboratory assays several days after the event. The aim of this study was to evaluate the possible changes in blood cell count and biochemical parameters observed in participants in a marathon 3 days before and 3 days after and before and immediately after a cardiopulmonary exercise test. Incremental cycle ergometry up to maximal capacity was performed in 7 marathon runners, 3 days before and 3 days after the race. The % peak oxygen consumption (peak %VO2) achieved was statistically significantly lower after than before the race (p = 0.02). No statistically significant differences were observed in cardiac frequency (p = 0.148) or blood cell count (p = 0.501). Also, the concentration of sodium, potassium, calcium, magnesium, lactate dehydrogenase (LDH), phosphocreatine kinase (CPK) and glucose, measured before and immediately after the pulmonary exercise test, did not differ significantly (p < 0.5). A significant percentage of the laboratory results were outside the standard reference rates. According to our data, exercise performance, as expressed by peak %VO2, continued to be decreased in marathon runners 3 days after the race. The blood cell count and biochemical parameters did not differ significantly but many marathon runners were outside the standard reference rates. Unfortunately, only 7 subjects were available for this study. Further studies with larger samples and with samples obtained at multiple times during and after exercise are needed to clarify the effects of long-distance running. Key words: Marathon—Biochemical parameters—Blood cells count—Exercise testing—Reference values—Sports medicine.
Correspondence to: K. Spiropoulos; email;
[email protected]
90
K. Spiropoulos and G. Trakada
Introduction The word marathon has its origin in Greek history. The runner Phidippides ran from Marathon to Athens to report the successful outcome of a battle. On arrival he said, ‘‘Rejoice! We conquer’’ («Nemij gjalem») then he collapsed and died. In the first modern Olympic games, a 42.2 km marathon race was initiated with approximately 25 runners. Spiros Louis was the winner in this first marathon race. Modern-day marathons draw thousands of participants. Several hundred runners require urgent medical attention during or after the race for exercise-associated collapse, and several deaths have occurred in recent years [1]. Changes in the laboratory parameters in marathon runners were first reported in 1903 [2] and have been partly confirmed later by other studies [3–5]. An increase in sodium concentration after long-distance running was observed by several investigators [6–10], but another study was unable to reproduce this finding [11]. These discrepancies in the results may be due to differences in time intervals for sampling after the race, degrees of fitness and environmental conditions [12]. Historically, international marathon rules limited water consumption, a practice strongly criticized in 1969 as ‘‘criminal folly’’ [13]. Since then, guidelines for fluid intake and electrolyte replacement of runners during a marathon have changed. Excessive concerns for dehydration and hyperthermia may have led to excessive fluid intake among runners [14–17]. This is best illustrated by comparing a 1970 study documenting a rise in sodium concentration in eight runners, each of whom consumed
