Creatine supplementation alters the response to a graded cycle ergometer test

Area of Science:

• Exercise Physiology
• Nutritional Biochemistry
• Sports Science

Background:

• Creatine is a popular supplement known for enhancing high-intensity exercise performance.
• Its effects on cardiorespiratory responses during graded exercise tests (GXTs) require further elucidation.
• Understanding these effects can inform training and supplementation strategies for athletes.

Purpose of the Study:

• To investigate the impact of creatine monohydrate supplementation on cardiorespiratory measures during a maximal GXT.
• To compare the effects of creatine supplementation (CS) against a placebo (PL) in trained adults.

Main Methods:

• Thirty-six trained adults completed two maximal GXTs on a cycle ergometer.
• Participants received either 5g of creatine monohydrate (CS) or placebo (PL) capsules four times daily for 7 days prior to the second GXT.
• Cardiorespiratory variables including total test time, oxygen consumption (VO2), heart rate, and ventilatory threshold were measured.

Main Results:

• Creatine supplementation (CS) significantly increased total GXT duration compared to baseline.
• CS led to significantly lower oxygen consumption (VO2) and heart rate at sub-maximal stages of the GXT.
• The ventilatory threshold occurred at a higher VO2 percentage of peak VO2 following CS, with no changes in peak VO2 for either CS or PL.

Conclusions:

• Creatine supplementation appears to alter metabolic system contributions during sub-maximal exercise.
• Trained individuals may perform sub-maximal workloads with a reduced oxygen cost and cardiovascular strain after creatine supplementation.
• These findings suggest creatine may enhance exercise economy and potentially delay fatigue during prolonged exertion.