5 km/h. Therefore, only in EAH-C-R4 we can assume that race speed was one of the factors which influenced EAH in our tested group. Fluid intake and race performance An important finding was the fact that in the ultra-MTBers (R1,R2), fluid intake was positively related to the number of kilometers achieved during 24-hour MTB race, which is in agreement with previous studies [3, 15, 25, 30, 47]. The

ultra-MTBers in the 24-hour MTB races R1 and R2 who drank more finished ahead of those who drank less. Furthermore, the ultra-MTBers in 24-hour MTB R2 with greater body mass losses achieved more kilometers in the race than those with lower body mass losses. In a recent study, Knechtle et al. showed similar findings in 24-hour ultra-runners [30]. In contrast to the ultra-MTBers in R1 and R2, in the ultra-runners in R3 fluid intake was not 4EGI-1 nmr related to race performance. We assume that the ultra-MTBers in R1 and R2 with a better race performance who did not develop EAH drank more than the others, however, still in accordance with IMMDA. In 219 runners in a 100-km ultra-marathon,

the faster runners had a support crew to provide drinks in contrast to the slower runners with no support crew [15]. Presumably, also our faster ultra-MTBers used this possibility of an additional fluid intake. In Knechtle et al. [15], PI3K Inhibitor Library order the faster athletes who probably had a higher sweating rate lost more fluids and consequently drank more fluids. The finding that fluid intake was positively correlated with race performance suggests that athletes in R1 and R2 were drinking appropriately. Faster athletes were working harder and required more water than slower athletes. We hypothesised that in cases of fluid overload, fluid intake would be related to Selleckchem Daporinad post-race body mass, Δ body mass, post-race plasma [Na+], and Δ plasma [Na+], respectively. In none of the races was fluid intake associated with post-race body mass, Δ body mass, Δ plasma [Na+], Δ plasma

volume, or Δ urine specific gravity. Another finding was that the finishers with a better race performance had lower post-race plasma [Na+] in R2 and R3, and a higher body mass loss in R2. Also in Hoffman et al. [11], Knechtle et al. [15] and Noakes [63] faster runners tended to lose more body mass. Likewise, fluid intake Flucloronide was negatively associated with Δ body mass in a recent study [25]. In a 24-hour running race Δ body mass showed no association with post-race plasma [Na+], however, no subject developed EAH [31]. Moreover, fluid intake correlated negatively to average running speed [31]. However, it is difficult to explain the decrease in body mass despite the increased fluid intake and the lower post-race plasma [Na+]. In a recent study, faster runners lost more body mass, and faster runners drank more fluid than slower runners [65]. Also, faster ultra-MTBers in R2 lost more body mass although they drank more.