Effects of Creatine Supplementation on Cognitive Measures and Markers of Acute Kidney Injury After Exercise in the Heat

The goal of this clinical trial is to learn if one week of creatine monohydrate supplementation alters inflammation, markers of acute kidney injury (AKI) risk, and cognitive performance in active, young, healthy volunteers. The main questions it aims to answer are: 1. Does one-week of creatine supplementation alter urinary markers of inflammation (cytokines) during exercise in the heat when compared to placebo? 2. Does one-week of creatine supplementation alter markers of AKI during exercise in the heat when compared to placebo? 3. Does one-week of creatine supplementation attenuate reductions in cognitive measures as a response of fatigue from exertional heat stress. Researchers will compare creatine monohydrate to a placebo (maltodextrin) to see if it alters inflammation, risk of acute kidney injury, and cognition after exercise in the heat. Participants will : * Complete a baseline aerobic exercise test to measure VO2max * Ingest 20 grams per day of creatine monohydrate or placebo (maltodextrin) for seven consecutive days * Cycle for 90 minutes in a heated chamber (38 C, \~40% relative humidity), alternating low- and high-intensity exercise * Self-collect urine before, after, and one-hour after exercise * Self-insert a rectal thermistor to measure core temperature * Complete cognitive tasks using the NIH toolbox before and after exercise to assess cognition * Complete the other condition (placebo or creatine) at least 21 days later