Effects of Sixty-Minute Race-Pace Running on Cardiac Stress Biomarkers in Recreational Distance Runners.

Sudden cardiac death (SCD) in athletes is generally rare, but a serious complication of cardiovascular events during exercise. Although regular intensive physical exercise is thought to be a key to a healthy life, unsuspected pathologies might lead to SCD during or after physical activity. Cardiac dysfunction and elevated cardiac markers have been reported after prolonged exercise. We sought to clarify the cardiac marker levels and hydration status in healthy, middle-aged male subjects for 24 hours after running sixty-minute at race-pace. The participants were 47.4±1.7 years old, had peak oxygen consumption of 47.1±1.2ml/kg/min, and regularly running 70.5±6.4km/week. Blood biomarkers were performed before, immediately after, at the fourth and twenty-fourth hours after running. Compared to initial values, creatine kinase (before:161.2±22.5U/L, 24 hours after:411.9±139.7U/L, p<0.001) and CK-MB (before:4.3±0.7ng/ml, 24 hours after:10.1±3.0ng/ml, p<0.001) were significantly elevated immediately after running and remained significantly high for 24 hours. In addition, Troponin-I (before:5.0±1.1ng/l, 4 hours after:81.5±29.9ng/l, p<0.001) and NT-proBNP (before: 31.2±5.3pg/ml, immediately after: 64.4±8.5pg/ml, p<0.01) were significantly elevated immediately after running and returned to baseline levels in 24 hours. The sixty-minute running caused significant dehydration, but athletes were rehydrated at the 4th hour in their voluntary hydration behavior. As the individual data were analyzed, it was interesting to see that some of the athletes had critical biomarker levels without any cardiac symptom. Our findings indicate that race-pace sixty-minute running may induce a possible transient silent myocardial injury in apparently healthy master runners. Detailed pre-participation screening of these athletes may be necessary to reduce the risk of SCD.

Effect of Regular Aerobic Training on Serum C-Reactive Protein and IL-6 Levels in Obese Women.

OBJECTIVE: This study's objective was to evaluate interleukin-6 (IL-6) and C-reactive protein (CRP) responses and performance changes in obese women after 8 weeks of aerobic training with an intensity of 50 to 60% of their individual maximum oxygen uptake (VO2). METHODS: A total of 18 sedentary women with an average age of 44.3 (± 1.9) years volunteered for this study. Over a period of 8 weeks, in 4 40-minute sessions per week, the participants walked at an exercise intensity that caused their heart rates to increase to levels corresponding to 50 to 60% of their VO2 peaks. Blood samples were collected from the participants, both when they were at rest and a couple of minutes after the end of the 1st exercise session. Sampling was repeated in the 4th and 8th weeks, before and after the last training sessions. RESULTS: The participants' body mass indices and weights decreased significantly by the end of the 8th week, while their maximum running speeds and VO2 peaks increased significantly. There were no differences in CRP or IL- 6 concentrations between the pre- and post-training sessions, but most of the participants' IL-6 levels dropped below 10 pg/ml after 8 weeks of training. CONCLUSION: Although no significant changes were observed in CRP or IL-6 concentrations, it is important to note that in response to aerobic training, the IL-6 levels of most of the participants fell to what is generally considered acceptable.