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To examine the effect of ascent rate on the induction of acute mountain sickness (AMS) in young adults during a climb to Jiaming Lake (3350 m) in Taiwan.Prospective, nonrandomized.Climb from 2370 to 3350 m.Young adults (aged 18 to 26 years) (N = 91) chose to participate in either the fast ascent (3 days; n = 43) or slow ascent (4 days; n = 48) group (1 and 2).Two criteria were used to define AMS. A Lake Louise score ≥3 and Lake Louise criteria [in the setting of a recent gain in altitude, the presence of headache and at least 1 of gastrointestinal discomfort (anorexia, nausea, or vomiting), fatigue or weakness, dizziness or lightheadedness, or difficulty sleeping].Heart rate, blood oxygen saturation (SaO2), and symptoms of AMS were monitored each morning and evening.Baseline characteristics were similar between groups, except for significant differences in history of alcohol consumption (P = 0.009) and climbing experience above 3000 m (P0.001). The incidence of AMS was not associated with the rate of ascent. Acute mountain sickness was most prevalent in group 1 on day 2 in the evening and in group 2 on day 3 in the evening. In both groups, AMS correlated with the initial reduction in SaO2. Body mass index (BMI)24 kg/m was identified as a significant risk factor for AMS.The development of AMS was closely associated with an initial reduction in SaO2. A BMI24 kg/m also contributed to the occurrence of AMS.These findings indicate that factors other than ascent rate should be considered when trying to ameliorate the risk of AMS.

To evaluate the prevalence and characteristics of acute kidney injury (AKI) in 100-km ultramarathon runners.Prospective observational study.The 2011 Soochow University ultramarathon, in which each athlete ran for 100 km.All Taiwanese entrants who participated in the 100-km race and lived in the northern part of Taiwan were invited to participate in the study.Acute kidney injury was defined using the Acute Kidney Injury Network criteria. Blood and urine samples were collected 1 week before, immediately after, and 1 day after the race.Immediately after the race, 85% (22) of the 26 subjects were diagnosed with AKI, 65% (16) with moderate dehydration, 23% (6) with muscle cramps, and 12% (3) with hematuria. Body weight was significantly decreased from prerace to all postrace measurements. Plasma levels of potassium ion, creatinine, renin, and aldosterone were significantly elevated immediately after the race and then significantly reduced 1 day after the race. Changes in plasma levels of sodium, creatine kinase, and creatine kinase-MB, as well as urine potassium and creatinine, were indicative of AKI.Transient AKI and muscle cramps are very common in 100-km ultramarathon runners. All transient ultra-runners who developed AKI in this study recovered their renal function 1 day later.Ultramarathon running is associated with a wide range of significant changes in hematological parameters, several of which can be associated with potentially serious renal and physiological abnormalities.

The principal objective of this study was to evaluate serial weight changes in athletes during 12- and 24-hour ultra-marathons and to correlate these changes with athletic performance, namely the distance covered.This was a prospective study.The 2003 Soochow University international ultra-marathon.Fifty-two race participants.12- or 24-hour ultra-marathon.Body weight changes were measured before, at 4-hour intervals during, and immediately after the 12- and 24-hour races.Significant overall decreases in body weight were apparent at the conclusion of both races. The mean relative body weight change after the 12-hour race was -2.89 +/- 1.56%, ranging from 0 to 6.5%. The mean relative body weight change after the 24-hour race was -5.05 +/- 2.28%, ranging from -0.77% to -11.40%. Of runners in the 24-hour race, 26% lost greater than 7% of baseline body weight during the race. During both the 12- and 24-hour races, the greatest weight change (decrease) occurred during the first 4 hours. Weight remained relatively stable after 8 hours, although a further decrease was apparent between 16 and 20 hours in the 24-hour participants. Weight change had no bearing on performance in the 12-hour race, whereas weight loss was positively associated with performance in the 24-hour race.Our findings demonstrate that the majority of weight decrease/dehydration in both the 12- and 24-hour races occurred during the first 8 hours. Hence, to maintain body weight, fluid intake should be optimized in the first 8 hours for both 12- and 24-hour runners and in 16 to 20 hours for 24-hour marathon runners.