The effects of creatine loading on thermoregulation and intermittent sprint exercise performance in a hot humid environment

J Strength Cond Res. 2007 Aug;21(3):655-60. doi: 10.1519/R-22186.1.

Abstract

The purpose of this study was to determine the effects creatine (Cr) loading may have on thermoregulatory responses during intermittent sprint exercise in a hot/humid environment. Ten physically active, heat-acclimatized men performed 2 familiarization sessions of an exercise test consisting of a 30-minute low-intensity warm-up followed by 6 x 10 second maximal sprints on a cycle ergometer in the heat (35 degrees C, 60% relative humidity). Subjects then participated in 2 different weeks of supplementation. The first week, subjects ingested 5 g of a placebo (P, maltodextrin) in 4 flavored drinks (20 g total) per day for 6 days and were retested on day 7. The second week was similar to the first except a similar dose (4 x 5 g/day) of creatine monohydrate (Cr) replaced maltodextrin in the flavored drinks. Six days of Cr supplementation produced a significant increase in body weight (+1.30 +/- 0.63 kg), whereas the P did not (+0.11 +/- 0.52 kg). Compared to preexercise measures, the exercise test in the heat produced a significant increase in core temperature, a loss of body water determined by body weight change during exercise, and a relative change in plasma volume (%PVC); however, these were not significantly different between P and Cr. Sprint performance was enhanced by Cr loading. Peak power and mean power were significantly higher during the intermittent sprint exercise test following 6 days of Cr supplementation. It appears that ingestion of Cr for 6 days does not produce any different thermoregulatory responses to intermittent sprint exercise and may augment sprint exercise performance in the heat.

MeSH terms

  • Adult
  • Analysis of Variance
  • Blood Volume
  • Body Mass Index
  • Body Temperature
  • Body Temperature Regulation / drug effects*
  • Body Temperature Regulation / physiology
  • Body Water / physiology
  • Body Weight
  • Creatine / administration & dosage
  • Creatine / pharmacology*
  • Dietary Supplements*
  • Hot Temperature
  • Humans
  • Humidity
  • Male
  • Running / physiology*
  • Sweating / physiology

Substances

  • Creatine