Plasma Hsp72 is higher in runners with more serious symptoms of exertional heat illness.

Exertional heat illness is a potentially fatal disorder that primarily affects fit young men. Plasma Hsp72 may be important in the aetiology of this disorder, acting as a danger signal to the organism and leading to an inflammatory response. The aim of this study was to determine whether patients with exertional heat illness following a 14 km run show a difference in their plasma Hsp72 concentration compared with control subjects who completed the event without incident. Patients (n = 22) and controls (n = 7) were all male. The patients were subdivided into two groups, one of which exhibited more serious symptoms indicating neurological impairment such as confusion (n = 13) (CNS) while the other group exhibited mild symptoms (MILD) (n = 9). The CNS group had a higher rectal temperature (T(rec)) compared with the control group (41.0 +/- 0.3 vs. 39.8 +/- 0.2 degrees C, P < 0.05, mean +/- SE). Immediately after the run plasma Hsp72 was higher in the CNS group compared to controls and patients with mild symptoms (37.9, 17.0, and 20.9 ng/ml, respectively, P < 0.005). There was a correlation between plasma Hsp72 and T(rec) measured immediately after the race (r = 0.597, P < 0.001, n = 29). However, core temperature was not the only factor leading to increased plasma Hsp72 immediately post race. Plasma Hsp72 was still higher in CNS patients compared with the control group (P < 0.05) when T(rec )was included as a covariate. In conclusion, plasma Hsp72 was elevated immediately after a 14 km run with higher levels in patients with more serious symptoms of heat illness.

Effects of creatine supplementation on aerobic power and cardiovascular structure and function.

This project aimed to determine 1) whether creatine (Cr) supplementation affects cardiovascular structure and function and 2) to examine its effect on aerobic power. Eighteen males undertook aerobic testing on a cycle ergometer and echocardiographic assessment of the heart. The experimental group (N = 9) ingested 20g x day(-1) of Cr for seven days followed by l0g x day(-1) for a further 21 days. The control group (N = 9) followed an identical protocol ingesting a placebo for the same period. Assessment was performed pre-, mid- (seven days) and post-testing (28 days). A MANOVA with repeated measures was used to test for group differences before and after supplementation. The Cr group demonstrated a significant increase in body mass for the pre-mid (1.0 +/- 0.6 kg) and the pre-post (1.5 +/- 0.7 kg) testing occasions. Submaximal VO2 decreased significantly from the pre-mid and pre-post testing occasions by between 4.8% to 11.4% with Cr supplementation at workloads of 75 W and 150 W. Other oxygen consumption measures and exercise time to exhaustion, for the Cr group, showed decreasing trends that approached significance. Additionally, there was a significant pre-post decrease in maximum heart rate of 3.7%. There were no changes in any of the echocardiographic or blood pressure measures for either group. The present results suggest short term Cr supplementation has no detectable negative effect on cardiac structure or function. Additionally, Cr ingestion improves submaximal cycling efficiency. These results suggest that the increase in efficiency may be related to peripheral factors such an increase in muscle phosphocreatine, rather than central changes.