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Objective To observe and assess the effects of full marathon on hemodynamics and cardiac electrophysiology of marathon amateurs without adverse event after the race.Methods Fiftyone subjects were included in the final analysis of the study,blood pressure,heart rate,body surface electrocardiogram (ECG) of all subjects under static status before the race and within (15-30) min after the race were detected,and sufficient amounts of the peripheral blood and the radial arterial blood specimens of all subjects under static status before the race and within (15-30) min after the race were collected instantly.The peripheral blood was used for measuring markers of muscle injury and NT-proBNP,and the radial arterial blood was taken for blood gas analysis.The QTc interval,QRS,PR interval,and QTd interval were recorded from the 12-lead ECG report.Results Compared with those under static status before the race,the systolic blood pressure,diastolic blood pressure,mean arterial blood pressure and heart rate of all the subjects within (15-30) min after the race were significantly higher (P＜0.05).When the markers of striated muscle injury were compared before and after the competition,levels of CK,cTNI,LDH,and myoglobin after the race were significantly increased compared with them under static status before the race (P ＜0.05),and the level of NT-proBNP after the race was also significantly increased compared with it before the race (P＜0.05).When blood gas analysis before the race was compared with that after the race,the PH values after race were significantly lower than it before race (P＜0.05).The level of lactic acid after the race was significantly higher than it before race (P＜0.05).After the race,the levels of PCO2,SBE and HCO3-decreased significantly compared with those before race (P＜0.05),and the QTc and QTd intervals after the race increased significantly compared with those before the race,however,the QTc interval and QTd interval for all subjects before and after the competition were within the normal range.Conclusions Full marathon significantly affect the myocardial electrophysiological markers of healthy amateur athletes without chronic diseases,but those markers fluctuate within the normal range.
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Objective To approach the effects of full Marathon on striated muscle and renal function of Marathon amateurs without complaints. Methods A prospective self-paired design study was conducted. The amateurs without body discomfort, hematuria, brown urine, or persistent muscle pain within 1 week after the 2012 Xiamen International Marathon Race were enrolled voluntarily. The peripheral blood and random urine specimens of all subjects under static status 1 week before the race and after the race instantly (within 10 minutes after finishing the race) were collected to detect markers of renal function and striated muscle injury. Results Sixty-one subjects were included in the final analysis of the study with full Marathon of 42.195 km and mean race time of (297.05± 55.60) minutes. Compared with those under static status before the race, the markers of renal function including the levels of urinary N-acetyl-beta-D-glucusamidase [NAG (U/L): 64.00 (54.50, 85.50) vs. 9.50 (8.10, 11.50)], urinary β2-microspheres protein [β2-MG (μg/L): 261.00 (128.50, 1 608.00) vs. 66.60 (33.75, 123.00)], random urinary creatinine [UCr (μmol/L): 19 066.56±10 938.31 vs. 5 872.52±4 363.20] and serum creatinine [SCr (μmol/L): 129.97±25.84 vs. 97.39±14.51] immediately after the race were significantly increased (all P < 0.01); the markers of muscle injury including the levels of serum creatine kinase [CK (U/L): 864.00 (504.00, 1 644.00) vs. 164.00 (128.00, 256.00)], lactic dehydrogenase [LDH (U/L): 383.26±141.69 vs. 182.23±41.12], myoglobin [Mb (mg/L): 1 880.00 (1 080.00, 3 300.00) vs. 42.00 (36.00, 54.50)], alanine aminotransferase [ALT (U/L): 27.0 (19.5, 38.0) vs. 24.0 (15.0, 29.5)] and aspartate transaminase [AST (U/L): 52.07±25.13 vs. 28.28±11.86] were also significantly increased (all P < 0.01), and the increase in CK, Mb, and LDH were more significant. It was shown by correlation analysis that CK after race was negatively correlated with age (r = -0.352, P = 0.005) and body mass index (r = -0.271, P = 0.035), and it was positively correlated with racing time (r = 0.387, P = 0.002) and urinary β2-MG after the race instantly (r = 0.364, P = 0.004). Mb after race was negatively correlated with body mass index (r = -0.331, P = 0.009), and it was positively correlated with urinary β2-MG after the race instantly (r = 0.315, P = 0.013). LDH after race was negatively correlated with age (r = -0.275, P = 0.032) and body mass index (r = -0.377, P = 0.003), and it was positively correlated with urinary β2-MG after the race instantly (r = 0.424, P = 0.001). Conclusion Full Marathon could significantly impact striated muscle and renal function of Marathon amateurs without complaints.
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We examined the relationship between serum magnesium (sMg) change and urinary Mg (uMg) excretion, lipid metabolism and hormonal responses induced by prolonged physical exercise. Six recreational runners voluntary participated in the study, and their sMg, uMg, serum lipid and circulatory levels of plasma hormones (ACTH, cortisol, ADH, aldosterone) were determined during a 1-week recovery period after a full-marathon race. Immediately after the race, fall of sMg was significant, but recovered to the pre-race level in the next day. Urinary Mg excretion decreased significantly after the race and the tubular reabsorption rate (%TRMg) was elevated for one week. The negative correlation between sMg and %TRMg suggested that a decreased level of sMg enhanced tubular reabsorption of Mg. On the other hand, no correlation was observed between the plasma hormone levels and %TRMg, thus hormonal responses induced by prolonged exercise had less effect on the tubular reabsorption of Mg. Therefore, fall of sMg after the full marathon race may not be a reflection of Mg depletion, but seems to be the result of a Mg shift to other regions (muscle, erythrocytes and adipose cells) from the serum. Increased level of serum FFA after the race suggested enhanced lipolysis, which might be a cause of sMg reduction.