The effects of creatine supplementation on thermoregulation and isokinetic muscular performance following acute (3-day) supplementation.

AIM: The purpose of this investigation was to determine the effects of 3 d of creatine supplementation on thermoregulation and isokinetic muscular performance. METHODS: Fourteen males performed two exercise bouts following 3 d of creatine supplementation and placebo. Subjects exercised for 60 min at 60-65% of VO2max in the heat followed by isokinetic muscular performance at 60, 180, and 300°·s(-1). Dependent variables for pre- and postexercise included nude body weight, urine specific gravity, and serum creatinine levels. Total body water, extracellular water and intracellular water were measured pre-exercise. Core temperature was assessed every 5 min during exercise. Peak torque and Fatigue Index were used to assess isokinetic muscular performance. RESULTS: Core temperature increased during the run for both conditions. Total body water and extracellular water were significantly greater (P<0.05) following creatine supplementation. No significant difference (P>0.05) was found between conditions for intracellular water, nude body weight, urine specific gravity, and serum creatinine. Pre-exercise scores for urine specific gravity and serum creatinine were significantly less (P<0.05) versus post-exercise. No significant differences (P>0.05) were found in peak torque values or Fatigue Index between conditions for each velocity. A significant (P<0.05) overall velocity effect was found for both flexion and extension. As velocity increased, mean peak torque values decreased. CONCLUSION: Three d of creatine supplementation does not affect thermoregulation during submaximal exercise in the heat and is not enough to elicit an ergogenic effect for isokinetic muscle performance following endurance activity.

Sister chromatid exchanges in peripheral lymphocytes in newborns treated with phototherapy and vitamin E.

A study was undertaken to determine whether blue fluorescent light might affect the sister chromatid exchange (SCE) frequency of peripheral lymphocytes in icteric newborns undergoing continuous phototherapy treatment (72 h). Also, the potential preventive effect of vitamin E on SCE frequency was studied in a subgroup of 11 preterm and 9 fullterm newborns after daily administration of vitamin E (46.44 mumol/kg/d, im). The results revealed that only the preterm icteric newborns showed an increase in mean SCE frequency of peripheral lymphocytes after phototherapy (9%, p = 0.02), but in no case did the highest SCEs/cell ratio exceed the normal values. No correlation was found between the average SCE rate and birth weight, gestational age or bilirubin levels. Also, no difference in SCEs was observed between newborns treated or untreated with vitamin E.