Creatine supplementation and age influence muscle metabolism during exercise

Area of Science:

• Exercise Physiology
• Nutritional Biochemistry
• Aging Research

Background:

• Middle-aged adults exhibit lower resting phosphocreatine (PCr) levels and PCr resynthesis rates compared to younger adults.
• Age-related declines in muscle bioenergetics may impact exercise performance and recovery.

Purpose of the Study:

• To investigate the effects of creatine supplementation on PCr metabolism and exercise performance in young and middle-aged men and women.
• To determine if creatine supplementation differentially affects PCr kinetics between age groups.

Main Methods:

• Participants (young and middle-aged) underwent single-leg knee-extension exercise within a magnetic resonance system.
• 31P magnetic resonance spectroscopy was used to measure muscle pH, Pi, PCr, and beta-ATP concentrations.
• Subjects received either placebo or creatine (0.3 g/kg/day) for 5 days prior to exercise trials.

Main Results:

• Middle-aged adults had lower baseline PCr and slower PCr resynthesis rates than young adults.
• Creatine supplementation increased resting PCr by 15% in young and 30% in middle-aged adults.
• Creatine normalized PCr resynthesis rates in middle-aged adults and increased time to exhaustion in both groups.

Conclusions:

• Creatine supplementation significantly improves PCr availability and resynthesis rates in both young and middle-aged adults.
• The ergogenic effects of creatine supplementation on muscle bioenergetics are more pronounced in middle-aged individuals.
• Creatine supplementation enhances exercise capacity and may mitigate age-related declines in muscle energy metabolism.